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1
Tuladhar, Kapil. "Lim-only domain proteins in developmental haematopoiesis." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:d6b73e89-7095-402f-9d9f-4d7837a4db00.
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The production of adult blood initiates from the haematopoietic stem cell (HSC). This clinically important cell has the capacity to maintain all blood lineages throughout the lifetime of an organism. HSCs emerge de novo from the haemogenic endothelium in the ventral wall of the embryonic dorsal aorta, from where they go on to seed adult sites of haematopoiesis. We have shown that Lmo4a is required for the emergence of HSCs in the zebrafish, and go on to demonstrate that Lmo4a regulates expression of the critical transcription factor, gata2a. Strikingly, both over- and under-expression of gata2a in the dorsal aorta severely diminishes HSC production. The LIM-only domain protein Lmo4 has previously been shown to interact with the known haematopoietic regulator, Ldb1. Together with our collaborators, we have identified novel binding partners of Lmo4 in mouse erythroleukaemic cells. Our functional analysis shows that many of these partners are also necessary for HSC emergence, thus revealing several new potential regulators of HSC formation. Given that these proteins were identified in an in vitro model of definitive erythropoiesis, it is remarkable that they also appear to act together in vivo at the level of HSC formation, and our data suggests that a transcriptional complex containing Lmo4 and these partners may directly repress gata2a. The related protein Lmo2 is also known to bind Ldb1. Together with Scl, Lmo2 is a master regulator of the haemangioblast programme. We have been utilising this activity, together with recent structural studies, to identify functionally important residues in the Lmo2 molecule. As a cell’s transcriptional programme drives both normal and pathological development, and misexpression of both Lmo2 and Lmo4 is involved in a variety of oncogenic states, the work presented in this thesis is likely to inform efforts to develop therapeutically relevant reagents.
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Pinto, Belinda Sophia Geyer Pamela Kent. "Understanding the role of LEM domain proteins in Drosophila development." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/421.
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Jurata, Linda Wagner. "Identification and analysis of the nuclear LIM domain interactor NLI /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1998. http://wwwlib.umi.com/cr/ucsd/fullcit?p9904815.
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Pinto, Belinda Sophia. "Understanding the role of LEM domain proteins in Drosophila development." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/421.
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The nuclear lamina is a filamentous network that underlies the nuclear envelope. Lamina components include the family of LEM domain (LEM-D) proteins, named for LAP2, emerin and MAN1. Mutations in genes encoding LEM-D proteins cause tissue-restricted human disease, even though these genes are globally expressed. To understand the contributions of the LEM-D proteins to nuclear lamina function, investigations of the Drosophila LEM-D proteins was undertaken. The Drosophila genome encodes four LEM-D proteins and this thesis describes work done on the Drosophila homologues of MAN1 and emerin, Drosophila MAN1 (dMAN1) and Otefin (Ote). Chapter 2 describes the generation and phenotypic analyses of dMAN1 mutants. These mutants display a range of tissue-specific defects associated with an increase in BMP/Dpp signaling. This suggests that dMAN1 downregulates BMP/Dpp signaling at the nuclear periphery. Chapter 3 describes the identification and phenotypic analyses of ote mutants. Loss of Ote is associated with a tissue-specific defect of the female germline where ote mutant females display defects in germline stem cell (GSC) maintenance. Loss of Ote causes defects in the germline cells, the cap cells of GSC niche and an increased sensitivity to Dpp signaling in both germline and somatic cells. These findings support models suggesting that laminopathies arise from dysfunction of the homeostasis in stem cell populations. Taken together, these studies suggest that the nuclear lamina may play tissue-specific roles through regulation of signal transduction pathways. Our data also support the use of Drosophila as a system to elucidate the mechanistic basis of diseases associated with defects in the nuclear lamina.
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Diefenbacher, Markus Elmar. "The transcriptional co-activator function of the LIM-domain protein nTrip6." Eggenstein-Leopoldshafen Forschungszentrum Karlsruhe GmbH, 2010. http://d-nb.info/1002907535/34.
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Nisevic, Ivan. "Detection and analysis of LIM domain-mediated interactions between transcription factors." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/15711.
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LIM-homeodomain (LIM-HD) proteins are a class of transcription factors involved in tissue specification and cell determination during development and are important in adult gene regulation. Six families of LIM-HD proteins, with two close paralogues in each family, are commonly found in tetrapods. They bind DNA via HDs, whereas their interactions with other proteins are mediated mainly by a pair of closely spaced LIM-domains (LIMs) in each protein. These proteins take part in various transcriptional complexes with Ldb1 and other cofactors that contain LIM-interaction domains (LIDs). In this thesis, protein-protein interactions of LIM-HD proteins were analysed in order to better understand the molecular mechanisms of transcriptional complex formation. Based on previous research that showed LIM-LID mediated interactions between Lhx3 and Isl1, yeast two-hybrid mating arrays were used to investigate how widespread protein-protein interactions are amongst the 12 mammalian LIM-HD proteins. Due to high levels of background growth in experiments with full-length proteins in pGBT9 vectors, the mating arrays focused on LIM-domain mediated interactions with full-length LIM-HDs or known LIDs. The arrays revealed a relatively strong interaction between Lhx3 (or Lhx4) and Isl1 (or Isl2), and detected weaker interactions between Lmx1a or Lmx1b and the LIM-binding domain of Isl1. The contribution of separate LIM-domains to the overall interaction with Ldb1 for each of the proteins was analysed by the same method. In most cases one of the LIM domains in each protein was able to independently interact with the LID domain of Ldb1 by yeast two-hybrid analysis indicating a dominant binder: LIM1 in Isl1 and Isl2, or LIM2 in other proteins. The exceptions were paralogues Lhx1 and Lhx5, for which no separate domain showed interaction with Ldb1LID by this approach. All tandem LIM-domain constructs showed a much stronger interaction with Ldb1LID than any isolated LIM domain supporting the idea that both domains are required for high affinity binding to Ldb1. Bimolecular Fluorescence Complementation experiments in yeast were designed and conducted as an alternative approach to test interactions between full-length LIM-HD proteins in the hope that a non-transcription based assay would lead to no or less background signal compared to yeast two-hybrid analysis. A plasmid system was developed based on existing yeast two-hybrid vectors using split green fluorescent proteins in place of domains from the GAL4 transcription factor. The assay was able to detect interactions between different LIMs and their partners but unfortunately interactions between full-length proteins were still difficult to detect due to low fluorescence, self-complementation in the controls and localization effects. LIM domains from LIM-HD proteins cannot be used in standard bimolecular binding assays because they tend to be insoluble and/or aggregate in the absence of a binding partner. Stable, soluble intramolecular ‘tethered complexes’ can be generated in which LIMs are tethered to Ldb1LID via a flexible linker. Introduction of a specific protease site into the tether allows the formation of intermolecular cut complexes, which have previously been used in homologous competition ELISA experiments. In this thesis attempts were made to develop more robust biophysical binding assays that could be used to assess the binding affinities of different LIMs for Ldb1LID. Several different labelling approaches were used to generate proteins with fluorescent tags for use in fluorescence anisotropy assays. In one of these approaches expressed protein ligation was applied to generate proteins with an N-terminal fluorescein. Although this labelling strategy was of low efficiency for LIMs-Ldb1LID tethered constructs, some preliminary fluorescence anisotropy experiments were carried out, which indicated that this could be a useful strategy providing a more efficient labelling strategy can be found. GFP-tagged tethered complexes were easier to generate, but could not be used in anisotropy experiments because of the intrinsically high anisotropy of GFP proteins. However, preliminary experiments indicated that these proteins can be used in clear native gel shift competition assays to compare binding affinities of different tandem LIM domains to Ldb1LID. Data presented in this thesis provide valuable insight into protein-protein interactions of LIM-HD transcription factors and the advantages, as well as disadvantages, of applied experimental approaches. The results and their implications are discussed, raising questions that can be resolved in future studies.
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Gu, Wenchao. "Exploring the roles of LIM domain binding proteins in zebrafish development." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:54f520f6-170a-480a-a195-1a0739055031.
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As some of the most important and widely utilised intercellular signalling molecules, transforming growth factor βs (TGFβs) play critical roles in normal development and in human disease. Establishing appropriate levels of signalling involves positive and negative feedback, driven by the same signal transduction components, but whether or how the two are distinguished has not previously been understood. Here we show that LIM domain binding proteins (Ldbs) drive the Smad6/7-mediated negative feedback of TGFβ signalling, but they are not required for the ligand-driven positive feedback or other downstream transcriptional activation. In Ldb-deficient zebrafish embryos, the homeostasis of TGFβ signalling is perturbed. As a consequence, signalling of TGFβ family members, Nodal and BMP, is stably enhanced, giving rise to excess mesoderm and endoderm, an effect that can be rescued by reducing Nodal and BMP. Later in development, conditional ldb2a knockdown causes defective vascular, angiogenic and haemogenic development, likely also by elevating TGFβ signalling. Thus, Ldbs control the homeostatic regulation of TGFβ signalling and therefore play critical roles in diverse developmental processes.
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Klaavuniemi, T. (Tuula). "PDZ-LIM domain proteins and α-actinin at the muscle Z-disk." Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514282647.
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Abstract
The Z-disk is a sophisticated structure that connects adjacent sarcomeres in striated muscle myofibrils. α-Actinin provides strength to the Z-disks by crosslinking the actin filaments of adjacent sarcomeres. α-Actinin is an antiparallel homodimer, composed of an N-terminal actin binding domain (ABD), the central rod domain, and two pairs of C-terminal EF-hands. The PDZ-LIM domain proteins interact with α-actinin at the Z-disk. Of these proteins, only the actinin-associated LIM protein (ALP), Z-band alternatively spliced PDZ-containing protein (ZASP/Cypher) and C-terminal LIM protein (CLP36) have a ZASP/Cypher-like (ZM) motif consisting of 26-27 conserved residues in the internal region between the PDZ and LIM domains. The aim of this work was to understand the molecular interplay between the ZM-motif containing members of the PDZ-LIM proteins and α-actinin. To unveil the biological relevance of the interaction between the PDZ-LIM proteins and α-actinin, naturally occurring human ZASP/Cypher mutations were analyzed.
Two interaction sites were found between ALP, CLP36 and α-actinin using recombinant purified proteins in surface plasmon resonance (SPR) analysis. The PDZ domain of ALP and CLP36 recognized the C-terminus of α-actinin, whereas the internal regions bound to the rod domain. Further characterization showed that the ALP internal region adopts and extended conformation when interacting with α-actinin and that the ZM-motif partly mediated the interaction, but did not define the entire interaction area. ZASP/Cypher also interacted and competed with ALP in binding to the rod domain. The internal fragments containing the ZM-motif were important for co-localization of ALP and ZASP/Cypher with α-actinin at the Z-disks and on stress fibers. The absence of ALP and ZASP/Cypher in focal contacts indicates that other interacting molecules, for instance vinculin and integrin, may compete in binding to the rod in these areas or additional proteins are required in targeting to these locations. The co-localization of the ZASP/Cypher with α-actinin could be released by disrupting the stress fibers leading to an accumulation of α-actinin in the cell periphery, whereas ZASP/Cypher was not in these areas. This suggests that an intact cytoskeleton is important for ZASP/Cypher interaction with α-actinin. Earlier studies have shown that mutations in the ZASP/Cypher internal region are associated with muscular diseases. These mutations, however, did not affect ZASP/Cypher co-localization with α-actinin or the stability of ZASP/Cypher proteins.
The Z-disk possesses a stretch sensor, which is involved in triggering hypertrophic growth as a compensatory mechanism to increased workloads. α-Actinin is a docking site of molecules that are involved in hypertrophic signaling cascades mediated by calsarcin-calcineurin and protein kinase C (PKC) isoforms. The internal interaction site may be involved in targeting PKCs, which bind to the LIM domains of ZASP/Cypher, to the Z-disks. The similar location of the internal interaction site with calsarcin on the rod suggests that ZASP/Cypher, ALP and CLP36 may regulate calsarcin-mediated hypertrophic signaling.
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Duan, Jie. "Active Control of Vehicle Powertrain Noise Applying Frequency Domain Filtered-x LMS Algorithm." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1243614246.
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Khurana, Bharat. "Characterization of DLIM1, a novel cytoskeleton-associated LIM domain containing protein of Dictyostelium discoideum." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=961945737.
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Diefenbacher, Markus Elmar [Verfasser]. "The transcriptional co-activator function of the LIM-domain protein nTrip6 / Markus Elmar Diefenbacher." Eggenstein-Leopoldshafen : Forschungszentrum Karlsruhe GmbH, 2010. http://d-nb.info/1002907535/34.
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Proeschel, Christoph Johann Wolfgang. "The cloning and characterisation of Lnk-1 : a novel LIM-domain containing protein kinase." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294778.
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Robertson, Neil. "Development and application of simple FRET-based methods for aggregation-prone LIM domain interactions." Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/16912.
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LIM-only (LMO) and LIM-homeodomain (LIM-HD) proteins are important mediators of cell specification, proliferation and differentiation. These transcription factors all contain two tandem LIM domains (LIM1+2), which are non-classical zinc finger motifs that mediate protein-protein interactions. Many co-factors of these proteins contain LIM interacting domains (LIDs). The LID is a ~30-residue intrinsically disordered region (IDR) that folds upon binding to LIM1+2 domains. LID:LIM1+2 interactions and the competition established through different combinations of different binding partners play an important role in neural development and breast cancer. The ability to estimate affinities for these interactions would help provide mechanistic insight into LMO and LIM-HD complex formation and regulation. However, the propensity of LIM1+2 domains from LMO/LIM-HD proteins to aggregate and precipitate during recombinant protein production have made it difficult to measure binding affinities for LID:LIM1+2 interactions. This thesis outlines the design, optimisation and application of a series of Förster Resonance Energy Transfer (FRET)-based approaches to study LID:LIM1+2 interactions. LIM1+2 aggregation is prevented by tethering the domains to a LID using a flexible polypeptide linker. The interacting domains are in turn fused to fluorescent proteins that are optimised for FRET. Specific proteolytic cleavage of the linker allows equilibrium binding constants and dissociation rates to be determined using homologous competition and dilution-based approaches. Through the application of these simple FRET-based binding methods, this thesis reveals previously unappreciated and unknown properties of LMO and LIM-HD proteins. This work provides tools for studying other aggregation-prone proteins, as well as general implications for the activity of transcription factors and IDR interactions.
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Bajic, Vladan. "DESIGN AND IMPLEMENTATION OF AN ADAPTIVE NOISE CANCELING SYSTEM IN WAVELET TRANSFORM DOMAIN." University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1132784671.
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Essawy, Nada. "Characterization of emerin LEM-domain missense mutations present in patients with exclusive atrial cardiac defects." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS299.
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La dystrophie musculaire d’Emery-Dreifuss (DMED) est l'une des dystrophies musculaires génétiques humaines les plus répandues. L'implication cardiaque dans la maladie est le symptôme qui met le plus la vie en danger et la principale cause de mortalité. La majorité des cas de son type liée à l’X sont dus à des mutations dans un gène codant pour une protéine de l'enveloppe nucléaire, l'émérine. Malgré les progrès considérables qui ont été réalisés en termes de caractérisation de la structure de l'émerine, ses différents partenaires de liaison, et ses fonctions dans le corps humain, le tableau est encore assez incomplet. Cinquante ans après que la DMED ait été documentée pour la première fois, les chercheurs n'ont toujours pas compris la pathophysiologie de la maladie. Il n'est donc pas surprenant qu'à ce jour, il n'existe pas de traitement décrit pour la DMED. Cette thèse est une première tentative pour caractériser trois mutations faux-sens du domaine LEM de l'émerine (P22L, ΔK37, et T43I) présentes chez des patients présentant uniquement des symptômes cardiaques. L'objectif principal de cette thèse est d'étudier l'effet des trois mutations sur la structure de l'émerine, son auto-assemblage, et les interactions avec certains de ses partenaires de liaison bien décrits. Le travail présenté souligne que malgré la présence des trois mutations dans la seule région repliée de l'émerine, les variants ne présentent aucun défaut global dans leur structure, à l'exception de la déstabilisation du domaine LEM du variant ΔK37. Il est important de noter que les mutants sont capables de s'auto-assembler, mais avec une cinétique de polymérisation rapide. En outre, l’étude a montré que les trois variants, bien que mutés dans le domaine de liaison à BAF, sont étonnamment capables de se lier à la protéine BAF. De plus, l'analyse ne révèle aucune différence dans les interactions des variants avec l’Ig-fold de la lamine A/C. De plus, il n'y a pas de défaut dans la phosphorylation du variant ΔK37 par la kinase Src. La caractérisation préliminaire de la mutation ΔK37 dans des fibroblastes humains immortalisés n'a pas montré de défauts manifestes en mécanobiologie et dans l'expression des protéines de l'enveloppe nucléaire ou du cytosquelette. Pris dans son ensemble, le travail présenté souligne que les trois mutations faux-sens de l’émerine ne provoquent aucun défaut dans plusieurs propriétés importantes de l'émerine, qui sont testées dans cette thèse. Sur la base des résultats de la recherche menée, nous avons acquis des connaissances considérables en ce qui concerne les conséquences des mutations d'intérêt. En d'autres termes, le travail présenté montre qu’il faut continuer les recherches sur l’émerine, afin d'explorer d'autres propriétés ou fonctions de cette protéine qui pourraient être associées à la physiopathologie de la DMEDEmery-Dreifuss Muscular Dystrophy (EDMD) is among the most widely common human genetic muscular dystrophies. The cardiac involvement in the disease is the most life-threatening symptom and the major cause of mortality. The majority of cases of its X-linked type are due to mutations in a gene encoding for the nuclear envelope protein, emerin. Despite the considerable advances that have been achieved in terms of the characterization of emerin structure, various binding partners, and functions in the human body, the picture is still rather incomplete. Fifty years now after EDMD had been first documented, researchers still fall short of understanding the pathophysiology of the disease. Thereby, it comes as no surprise that, to date, there is no described treatment of EDMD. Accordingly, this thesis is an initial attempt to characterize three emerin LEM-domain missense mutations (P22L, ΔK37, and T43I) present in patients with exclusive cardiac defects. The main objective of this thesis is to investigate the effect of the three mutations on: emerin structure, its self-assembly, and interactions with some of its well-described binding partners. The presented work highlights that albeit the localization of the three mutations in the only folded region of emerin, the variants show no global defect in their structure, except for the destabilization of the LEM-domain of the variant ΔK37. Importantly, the mutants are able to self-assemble, yet with astonishing fast polymerization kinetics. In addition, the investigations have illustrated that the three variants, despite the presence of the mutations in the BAF-binding domain, are surprisingly capable of binding BAF. The analysis did not reveal any differences in the mutants binding to Ig-fold domain of lamin A/C. Further, there is no defect in ΔK37 phosphorylation by Src kinase. Also, preliminary characterization of the ΔK37 mutation in immortalized human fibroblasts has featured no overt defects in mechanobiology, and in the expression of nuclear envelope or cytoskeletal proteins. Taken all together, the presented work outlines that the three emerin missense mutations display no defects in several prominent emerin properties, which are questioned in this thesis. On the basis of the results of the conducted research, considerable insight has been gained with regard to the consequences of the mutations of interest. In other words, the presented work lends support to following investigations in order to explore other unquestioned properties or functions of emerin that might be associated with the pathophysiology of EDMD
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Salpingidou, Georgia. "The role of emerin and LEM domain proteins in nuclear envelope assembly and cytoskeleton organisation." Thesis, Durham University, 2005. http://etheses.dur.ac.uk/2203/.
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The nuclear envelope (NE) plays a fundamental role in the cell by separating nuclear from cytoplasmic activities, and mutations in NE proteins have been associated with a diverse array of diseases. In the present study the Xenopus cell-free system was used to investigate the function of the inner nuclear membrane protein, emerin, which is associated with the Emery-Dreifuss muscular dystrophy (X-EDMD).Initially, the order and dynamics of NE assembly in Xenopus egg extracts have been investigated. Using a panel of antibodies it was shown that NE assembly proceeds by the ordered recruitment of two membrane populations, Nuclear Envelope Precursor vesicles -A and -B (NEP-A and NEP-B), to chromatin. As shown by immunofluorescence NEP-B vesicles, together with nucleoporins (Nups), appear first around chromatin at about ten minutes after initiation of NE assembly while NEP-A vesicles appear at a later stage, at about twenty minutes. To investigate the role of different emerin domains in this process, four human emerin peptides consisting of amino acids (aa) 1-70, 1-176, 1-220 and 73-180 were added individually to Xenopus nuclear assembly reactions at different concentrations and the effect on nuclear vesicle recruitment and NPC formation was monitored. Immunofluorescence analysis showed that peptides containing the LEM domain of emerin interfere with a correct NE assembly by inhibiting chromatin decondensation and recruitment of membranes to chromatin. This inhibitory effect was shown to be exerted mainly on NEP-A membranes and on Nup62 and Nupl53. By the use of two antibodies, raised against the LEM domain of human emerin and LAP2ß, two proteins of 30 and 36 kD, respectively, were identified in Xenopus. Both proteins were shown to reside in the NEP-A membrane population providing an explanation for the preferential inhibition of NEP-A recruitment to chromatin by exogenously added LEM domain containing emerin peptides. To further investigate whether the domain specific inhibitory effects of emerin on nuclear assembly correlate with specific interacting proteins, co-precipitation experiments were performed to identify emerin binding proteins in the Xenopus cytosol. From these experiments ß -tubulin was identified as a protein able to interact with emerin peptides 1-70 and 73-180. Staining of X-EDMD cells, which lack emerin, with a ß -tubulin antibody revealed no alterations in the organisation of the microtubule (MT) network. The most prominent effect of emerin mutations regarding MTs was the position of the Microtubule Organising Centre (MTOC) relative to the NE. Staining for the centrosomal protein pericentrin revealed a mis-localisation of the MTOC away from the NE in X-EDMD cell lines at distances at least double compared to control cells.
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Barton, Lacy Jo. "Defining the role of the nuclear lamina LEM Domain protein Otefin in germline stem cells." Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/2043.
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The contents of nuclei are highly organized. Nuclear organization is facilitated by a dense protein network, called the nuclear lamina, which underlies the nuclear envelope. The nuclear lamina is composed of filamentous lamins and more than eighty lamin-associated proteins (LAPs). Among the first LAPs identified are LEM Domain (LEM-D) proteins, named after LAP2, emerin and MAN1. LEM-D proteins have many shared and unique functions that include providing structural support to the nucleus, regulating signal transduction pathways and gene expression, facilitating proper progression through the cell cycle and maintaining chromatin attachments at the nuclear periphery. Despite requirements for these processes in all cell types, loss of globally expressed LEM-D proteins causes tissue-restricted defects. Identification of the primary function in tissues susceptible to LEM-D protein loss is a persistent challenge in the nuclear lamina field.
Research described here uses Drosophila as a model to understand LEM-D protein function. Loss of the Drosophila emerin homologue Otefin (Ote) causes a complex phenotype in the ovary wherein both somatic and germline cells are compromised. Using tissue-restricted expression experiments, it was determined that Ote function is only required in germline stem cells (GSCs) to maintain all cells in the ovary. Developmental, molecular and genetic analyses revealed that the primary defect in ote mutant ovaries is an early block in germline differentiation, followed by GSC death. Genetic rescue experiments revealed that both of these GSC defects are due to the activation of the DNA Damage Response (DDR) proteins ATR and Chk2. Interestingly, activation of ATR and Chk2 occurs independent of detectable canonical DDR triggers, including DNA damage. Immunohistochemical analyses suggest that Ote might be regulating chromatin condensation and/or heterochromatin organization in GSCs. Through studies of Ote, a rescue method was discovered that involves culturing animals at elevated temperatures. This novel rescue strategy, termed hyperthermia, acts independent of ATR or Chk2 inhibition. Interestingly, elevated temperatures leads to chromatin decondensation in Drosophila, suggesting that hyperthermia may rescue oogenesis by alleviating chromatin defects observed in ote mutant germ cells. Together, results from experiments discussed herein dissect a complex ovary phenotype to reveal the critical requirement for a nuclear lamina LEM-D protein.
Investigations into Ote function have revealed several aspects of GSC biology. The ATR/Chk2 checkpoint activated in the absence of Ote uncovered a previously unidentified cause of female GSC death. Further, findings that ATR and Chk2 are activated in the absence of canonical triggers suggest that GSCs possess a system to monitor defects or changes in the nucleus that do not involve DNA damage. Therefore, studies of Ote function and ote mutant phenotypes have uncovered valuable insights into LEM-D protein function and revealed the existence of novel conditions required for GSC maintenance.
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Guruswamy, Aarumugam Bhupathi Rajan. "Independent Domain of Symmetric Encryption using Least SignificantBit : Computer Vision, Steganography and Cryptography Techniques." Thesis, Högskolan Dalarna, Datateknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:du-10063.
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The rapid development of data transfer through internet made it easier to send the data accurate and faster to the destination. There are many transmission media to transfer the data to destination like e-mails; at the same time it is may be easier to modify and misuse the valuable information through hacking. So, in order to transfer the data securely to the destination without any modifications, there are many approaches like cryptography and steganography. This paper deals with the image steganography as well as with the different security issues, general overview of cryptography, steganography and digital watermarking approaches. The problem of copyright violation of multimedia data has increased due to the enormous growth of computer networks that provides fast and error free transmission of any unauthorized duplicate and possibly manipulated copy of multimedia information. In order to be effective for copyright protection, digital watermark must be robust which are difficult to remove from the object in which they are embedded despite a variety of possible attacks. The message to be send safe and secure, we use watermarking. We use invisible watermarking to embed the message using LSB (Least Significant Bit) steganographic technique. The standard LSB technique embed the message in every pixel, but my contribution for this proposed watermarking, works with the hint for embedding the message only on the image edges alone. If the hacker knows that the system uses LSB technique also, it cannot decrypt correct message. To make my system robust and secure, we added cryptography algorithm as Vigenere square. Whereas the message is transmitted in cipher text and its added advantage to the proposed system. The standard Vigenere square algorithm works with either lower case or upper case. The proposed cryptography algorithm is Vigenere square with extension of numbers also. We can keep the crypto key with combination of characters and numbers. So by using these modifications and updating in this existing algorithm and combination of cryptography and steganography method we develop a secure and strong watermarking method. Performance of this watermarking scheme has been analyzed by evaluating the robustness of the algorithm with PSNR (Peak Signal to Noise Ratio) and MSE (Mean Square Error) against the quality of the image for large amount of data. While coming to see results of the proposed encryption, higher value of 89dB of PSNR with small value of MSE is 0.0017. Then it seems the proposed watermarking system is secure and robust for hiding secure information in any digital system, because this system collect the properties of both steganography and cryptography sciences.
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Anantharaman, B. "Compressed Domain Processing of MPEG Audio." Thesis, Indian Institute of Science, 2001. https://etd.iisc.ac.in/handle/2005/3914.
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MPEG audio compression techniques significantly reduces the storage and transmission requirements for high quality digital audio. However, compression complicates the processing of audio in many applications. If a compressed audio signal is to be processed, a direct method would be to decode the compressed signal, process the decoded signal and re-encode it. This is computationally expensive due to the complexity of the MPEG filter bank. This thesis deals with processing of MPEG compressed audio. The main contributions of this thesis are
a) Extracting wavelet coefficients in the MPEG compressed domain.
b) Wavelet based pitch extraction in MPEG compressed domain.
c) Time Scale Modifications of MPEG audio.
d) Watermarking of MPEG audio.
The research contributions starts with a technique for calculating several levels of wavelet coefficients from the output of the MPEG analysis filter bank. The technique exploits the toeplitz structure which arises when the MPEG and wavelet filter banks are represented in a matrix form, The computational complexity for extracting several levels of wavelet coefficients after decoding the compressed signal and directly from the output of the MPEG analysis filter bank are compared. The proposed technique is found to be computationally efficient for extracting higher levels of wavelet coefficients.
Extracting pitch in the compressed domain becomes essential when large multimedia databases need to be indexed. For example one may be interested in listening to a particular speaker or to listen to male female audio segments in a multimedia document. For this application, pitch information is one of the very basic and important features required. Pitch is basically the time interval between two successive glottal closures. Glottal closures are accompanied by sharp transients in the speech signal which in turn gives rise to a local maxima in the wavelet coefficients. Pitch can be calculated by finding the time interval between two successive maxima in the wavelet coefficients. It is shown that the computational complexity for extracting pitch in the compressed domain is less than 7% of the uncompressed domain processing. An algorithm for extracting pitch in the compressed domain is proposed. The result of this algorithm for synthetic signals, and utterances of words by male/female is reported.
In a number of important applications, one needs to modify an audio signal to render it more useful than its original. Typical applications include changing the time evolution of an audio signal (increase or decrease the rate of articulation of a speaker),or to adapt a given audio sequence to a given video sequence. In this thesis, time scale modifications are obtained in the subband domain such that when the modified subband signals are given to the MPEG synthesis filter bank, the desired time scale modification of the decoded signal is achieved. This is done by making use of sinusoidal modeling [I]. Here, each of the subband signal is modeled in terms of parameters such as amplitude phase and frequencies and are subsequently synthesised by using these parameters with Ls = k La where Ls is the length of the synthesis window , k is the time scale factor and La is the length of the analysis window. As the PCM version of the time scaled signal is not available, psychoacoustic model based bit allocation cannot be used. Hence a new bit allocation is done by using a subband coding algorithm. This method has been satisfactorily tested for time scale expansion and compression of speech and music signals.
The recent growth of multimedia systems has increased the need for protecting digital media. Digital watermarking has been proposed as a method for protecting digital documents. The watermark needs to be added to the signal in such a way that it does not cause audible distortions. However the idea behind the lossy MPEC encoders is to remove or make insignificant those portions of the signal which does not affect human hearing. This renders the watermark insignificant and hence proving ownership of the signal becomes difficult when an audio signal is compressed. The existing compressed domain methods merely change the bits or the scale factors according to a key. Though simple, these methods are not robust to attacks. Further these methods require original signal to be available in the verification process. In this thesis we propose a watermarking method based on spread spectrum technique which does not require original signal during the verification process. It is also shown to be more robust than the existing methods. In our method the watermark is spread across many subband samples. Here two factors need to be considered, a) the watermark is to be embedded only in those subbands which will make the addition of the noise inaudible. b) The watermark should be added to those subbands which has sufficient bit allocation so that the watermark does not become insignificant due to lack of bit allocation. Embedding the watermark in the lower subbands would cause distortion and in the higher subbands would prove futile as the bit allocation in these subbands are practically zero. Considering a11 these factors, one can introduce noise to samples across many frames corresponding to subbands 4 to 8. In the verification process, it is sufficient to have the key/code and the possibly attacked signal. This method has been satisfactorily tested for robustness to scalefactor, LSB change and MPEG decoding and re-encoding.
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Anantharaman, B. "Compressed Domain Processing of MPEG Audio." Thesis, Indian Institute of Science, 2001. http://hdl.handle.net/2005/68.
Full textAbstract:
MPEG audio compression techniques significantly reduces the storage and transmission requirements for high quality digital audio. However, compression complicates the processing of audio in many applications. If a compressed audio signal is to be processed, a direct method would be to decode the compressed signal, process the decoded signal and re-encode it. This is computationally expensive due to the complexity of the MPEG filter bank. This thesis deals with processing of MPEG compressed audio. The main contributions of this thesis are
a) Extracting wavelet coefficients in the MPEG compressed domain.
b) Wavelet based pitch extraction in MPEG compressed domain.
c) Time Scale Modifications of MPEG audio.
d) Watermarking of MPEG audio.
The research contributions starts with a technique for calculating several levels of wavelet coefficients from the output of the MPEG analysis filter bank. The technique exploits the toeplitz structure which arises when the MPEG and wavelet filter banks are represented in a matrix form, The computational complexity for extracting several levels of wavelet coefficients after decoding the compressed signal and directly from the output of the MPEG analysis filter bank are compared. The proposed technique is found to be computationally efficient for extracting higher levels of wavelet coefficients.
Extracting pitch in the compressed domain becomes essential when large multimedia databases need to be indexed. For example one may be interested in listening to a particular speaker or to listen to male female audio segments in a multimedia document. For this application, pitch information is one of the very basic and important features required. Pitch is basically the time interval between two successive glottal closures. Glottal closures are accompanied by sharp transients in the speech signal which in turn gives rise to a local maxima in the wavelet coefficients. Pitch can be calculated by finding the time interval between two successive maxima in the wavelet coefficients. It is shown that the computational complexity for extracting pitch in the compressed domain is less than 7% of the uncompressed domain processing. An algorithm for extracting pitch in the compressed domain is proposed. The result of this algorithm for synthetic signals, and utterances of words by male/female is reported.
In a number of important applications, one needs to modify an audio signal to render it more useful than its original. Typical applications include changing the time evolution of an audio signal (increase or decrease the rate of articulation of a speaker),or to adapt a given audio sequence to a given video sequence. In this thesis, time scale modifications are obtained in the subband domain such that when the modified subband signals are given to the MPEG synthesis filter bank, the desired time scale modification of the decoded signal is achieved. This is done by making use of sinusoidal modeling [I]. Here, each of the subband signal is modeled in terms of parameters such as amplitude phase and frequencies and are subsequently synthesised by using these parameters with Ls = k La where Ls is the length of the synthesis window , k is the time scale factor and La is the length of the analysis window. As the PCM version of the time scaled signal is not available, psychoacoustic model based bit allocation cannot be used. Hence a new bit allocation is done by using a subband coding algorithm. This method has been satisfactorily tested for time scale expansion and compression of speech and music signals.
The recent growth of multimedia systems has increased the need for protecting digital media. Digital watermarking has been proposed as a method for protecting digital documents. The watermark needs to be added to the signal in such a way that it does not cause audible distortions. However the idea behind the lossy MPEC encoders is to remove or make insignificant those portions of the signal which does not affect human hearing. This renders the watermark insignificant and hence proving ownership of the signal becomes difficult when an audio signal is compressed. The existing compressed domain methods merely change the bits or the scale factors according to a key. Though simple, these methods are not robust to attacks. Further these methods require original signal to be available in the verification process. In this thesis we propose a watermarking method based on spread spectrum technique which does not require original signal during the verification process. It is also shown to be more robust than the existing methods. In our method the watermark is spread across many subband samples. Here two factors need to be considered, a) the watermark is to be embedded only in those subbands which will make the addition of the noise inaudible. b) The watermark should be added to those subbands which has sufficient bit allocation so that the watermark does not become insignificant due to lack of bit allocation. Embedding the watermark in the lower subbands would cause distortion and in the higher subbands would prove futile as the bit allocation in these subbands are practically zero. Considering a11 these factors, one can introduce noise to samples across many frames corresponding to subbands 4 to 8. In the verification process, it is sufficient to have the key/code and the possibly attacked signal. This method has been satisfactorily tested for robustness to scalefactor, LSB change and MPEG decoding and re-encoding.
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Diefenbacher, Markus Elmar [Verfasser], and A. [Akademischer Betreuer] Cato. "The transcriptional co-activator function of the LIM-domain protein nTrip6 / Markus Elmar Diefenbacher. Betreuer: A. Cato." Karlsruhe : KIT-Bibliothek, 2009. http://d-nb.info/1014222877/34.
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Essawy, Nada [Verfasser]. "Characterization of emerin LEM-domain missense mutations present in patients with exclusive atrial cardiac defects / Nada Essawy." Berlin : Freie Universität Berlin, 2019. http://d-nb.info/1179277864/34.
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Arnaud, Dominique. "Identification et caractérisation de la famille de protéines à domaine LIM chez le peuplier." Orléans, 2007. http://www.theses.fr/2007ORLE2035.
Full textAbstract:
Les gènes LIM de plantes sont exprimés dans tous les tissus ou spécifiquement dans le pollen. Les protéines à domaine LIM de plantes auraient une double fonction cellulaire agissant comme facteur de transcription activant la synthèse de la lignine ou comme protéine liant et empaquetant les filaments d’actines. Ce travail de thèse présente la première étude de la famille de protéines à domaine LIM chez le peuplier. Six paires de gènes LIM ont été identifiées dans le génome séquencé de Populus trichocarpa, et la comparaison avec les modèles de gènes LIM d’Arabidopsis et de riz révèle une structure génomique très conservée. L’analyse de 155 unigènes LIM additionnels chez les plantes a permis de définir quatre groupes phylogénétiques distincts divisés en plusieurs sous-groupes monophylétiques différant par des spécificités d’expression tissulaires et/ou par des spécificités taxonomiques. L’analyse de l’expression de ces gènes par RT-PCR semi quantitative dans différents tissus et organes de peuplier montre que certains gènes sont préférentiellement exprimés dans les tissus vasculaires, alors que d’autres sont fortement exprimés dans le pollen ou dans les fibres de coton. La protéine PtaGLIM1a qui définit un nouveau sous-groupe FLIM1, est fortement exprimée dans le bois de tension. De plus, cette protéine subirait des modifications post-traductionnelles particulières dans le bois. Enfin, ces résultats suggèrent un rôle des protéines LIM de plantes dans certains aspects de l’expansion cellulaire.
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Bossenz, Michael. "In-vivo-Analyse des LIM-Domäne-bindenden Kofaktors RLIM in Vertebraten." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971998973.
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Wang, Hui. "The Roles of a LIM Domain Protein, Hic-5/ARA55, in TGF-β Signaling in Prostate Cancer Cells." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1220931692.
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Banthien, Nils [Verfasser]. "The four-and-a-half-LIM-domain Protein FHL2 is a novel regulator of pulmonary fibrosis / Nils Banthien." Gießen : Universitätsbibliothek, 2020. http://d-nb.info/1216142955/34.
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Emond, Julien. "Contribution à l'étude des structures passives verre-silicium dans le domaine millimétrique." Phd thesis, Université Paris-Est, 2010. http://tel.archives-ouvertes.fr/tel-00600678.
Full textAbstract:
Nous proposons dans cette thèse de nouvelles structures à faibles pertes en vue de leur utilisation dans les bandes millimétriques. L'hypothèse forte sur laquelle es t construite notre étude est que la présence du silicium permet d'envisager une intégration plus facile des circuits. Pour ce faire nous avons étudié les caractéristiques électriques des lignes inversées silicium-verre à 60 GHz ainsi que la ligne de Goubau sur silicium aux mêmes fréquences. Nous nous sommes focalisés sur l'étude des pertes des lignes. Les simulations présentées jusqu'à 60 GHz ont montré que les qualités de la technologie verre-silicium sont bonnes en termes de paramètres hyperfréquences. Nous proposons donc d'utiliser plutôt le verre pour la partie passive et le silicium pour la partie active. Nous montrons ainsi que cette technologie admet la réalisation des fonctions diverses et qu'elle est susceptible de permettre l'obtention de systèmes intégrés
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Nahar, Taslima [Verfasser], and Markus [Akademischer Betreuer] Hecker. "Role of the lim-domain proteins LPP and ZYXIN in hypertension-induced cardiovascular remodeling / Taslima Nahar ; Betreuer: Markus Hecker." Heidelberg : Universitätsbibliothek Heidelberg, 2017. http://d-nb.info/1178010651/34.
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Terano, Tomo. "Transcriptional control of fetal liver hematopoiesis : dominant negative effect of the overexpression of the LIM domain mutants of LMO2." Kyoto University, 2005. http://hdl.handle.net/2433/144782.
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Raskin, Anna Maria. "Four and half LIM Domain-1 protein and its role in passive mechanics and hypertrophic signaling of the heart." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3320727.
Full textAbstract:
Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed October 3, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
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Nguyen, Ngoc Hung, Majid Dowlatnia, and Azhar Sarfraz. "Implementation of the LMS and NLMS algorithms for Acoustic Echo Cancellationin teleconference systemusing MATLAB." Thesis, Växjö University, School of Mathematics and Systems Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-6368.
Full textAbstract:
In hands-free telephony and in teleconference systems, the main aim is to provide agood free voice quality when two or more people communicate from different places.The problem often arises during the conversation is the creation of acoustic echo. Thisproblem will cause the bad quality of voice signal and thus talkers could not hearclearly the content of the conversation, even thought lost the important information.This acoustic echo is actually the noise which is created by the reflection of soundwaves by the wall of the room and the other things exist in the room. The mainobjective for engineers is the cancellation of this acoustic echo and provides an echofree environment for speakers during conversation. For this purpose, scientists designdifferent adaptive filter algorithms. Our thesis is also to study and simulate theacoustics echo cancellation by using different adaptive algorithms.
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König, Katharina [Verfasser]. "The role of Four-and-a-half LIM domain protein 2 in dendritic cell migration / Katharina König. Mathematisch-Naturwissenschaftliche Fakultät." Bonn : Universitäts- und Landesbibliothek Bonn, 2011. http://d-nb.info/1018829962/34.
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MUNDEL, CHRISTOPHE. "Etude de wlim-1, une proteine a domaines lim de tournesol (helianthus annuus l. )." Université Louis Pasteur (Strasbourg) (1971-2008), 1999. http://www.theses.fr/1999STR13024.
Full textAbstract:
Les proteines lim sont caracterisees par la presence d'un domaine en double doigt de zinc particulier : le domaine lim. Elles sont impliquees dans des phenomenes de differenciation cellulaire, morphogenese et developpement. Wlim-1 est une proteine a domaines lim dont l'adnc a ete isole a partir d'une banque d'adnc de tournesol helianthus annuus l. Elle comporte deux domaines lim separes par un long domaine interlim et presente des homologies de structure et de sequence avec les proteines lim animales mlp et crp, des proteines lim impliquees dans l'organisation du cytosquelette a actine. Le gene wlim-1 correspondant a ete isole et sequence. Des experiences d'immunodetection indiquent que la proteine est presente dans de nombreux organes de la plante sous au moins deux formes. Des immunolocalisations realisees sur les feuilles, tiges, ovaires et racines montrent que wlim-1 est presente dans de nombreux tissus au sein de chaque organe avec trois localisations : nucleaire, cytoplasmique ou au niveau des plastes. Lors de ces experiences, nous avons remarque que wlim-1 semble se concentrer entre les deux lots de chromosomes dans des cellules en division (anaphase et telophase). Cette localisation nous ammene a postuler un role de wlim-1 dans la division cellulaire.
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Baron, Kyla Doreen. "The Role of LMO4 in the Regulation of SLK Localization & Activation within Migrating Cells and in Murine Mammary Tumorigenesis." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34195.
Full textAbstract:
The Ste20-like kinase SLK plays a pivotal role in cell migration and focal adhesion turnover. SLK activity is regulated by the LIM domain-binding proteins Ldb1/2. In addition to playing role in tumor initiation and progression, these proteins have been demonstrated to interact with LMO4. Therefore, this project assessed the ability of LMO4 to interact and regulate SLK activity. Results show that LMO4 can directly bind to SLK and activate its kinase activity. LMO4 can be co-precipitated with SLK following the induction of cell migration by scratch wounding. Cre deletion of LMO4 inhibits cell migration and SLK activation, and impairs Ldb1 and SLK recruitment to the leading edge of migrating cells. Src/Yes/Fyn-deficient cells (SYF) express very low levels of LMO4 and do not recruit SLK to the leading edge. Src-family kinase inhibition impairs SLK recruitment to the leading edge, suggesting that both expression of LMO4 and the recruitment of SLK to the leading edge require c-Src activity. In conclusion, cell migration and activation of SLK requires its recruitment to the leading edge by LMO4 in a Src-dependent manner. This study also investigated whether LMO4 deletion through MMTV-Cre-driven excision would impair mammary tumorigenesis in a PyMT mouse model of breast cancer. No difference in Overall Survival was observed between animals with and without LMO4 expression. Western blot analysis and IHC showed that tumors expressed LMO4 protein in animals genotyped as Cre-positive. This result suggests that expression of LMO4 is required for tumor initiation in the PyMT model of murine mammary carcinoma. This project has established a novel cytosolic role for the transcriptional co-activator LMO4 and validated it’s involvement in the regulation of SLK and cell migration. This pathway may provide a novel therapeutic strategy as LMO4 appears to be critical to the initiation and progression of breast cancer.
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Bridge, Katherine S. "Regulation of HIF-l and the hypoxic response by the tumour suppressor LIMDl and LIM domains-containing proteins." Thesis, University of Nottingham, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.606229.
Full textAbstract:
In order to survive in a given environment, adequate levels of oxygen are required throughout cells and tissues, as defined by cellular function and tissue type. Rapid reaction and adaption of a cell or tissue to low p02 (hypoxia) can enable it to remain viable, thus reducing potential damage to the organism. The hypoxic response signalling pathway is activated by hypoxia inducible factors (HIFs); these transcription factors activate genes whose products enable the cell to adapt to hypoxic conditions, including vascular endothelial growth factor (VEGF) and erythropoietin (EPO) . Under normal oxygen conditions (normoxia), the HIF-la subunit is rapidly degraded as a result of hydroxylation by the prolyl hydroxylase domain proteins (PHDl-3) and subsequent binding of the von Hippel-Lindau protein (VHL), which induces ubiquitination and degradation of HIF-la by the 265 proteasome. Data presented in this thesis identify the LlM domains-containing tumour suppressor gene product LlMD1, as well as other members of the ZYX class of LlM domain proteins, as regulators of HIF-l and the hypoxic response. LlMDl interacts with the PHDs and VHL at distinct sites to facilitate efficient HIF-la degradation by bringing the hydroxylase and ubiquitinase enzymes into close proximity. LlMDl enhances HIF-la degradation via the oxygen dependent degradation (ODD) domain and represses HIF-l transcriptional activity; these effects are dependent upon the ability of LlMDl to engage PHD2/VHL. In addition to LlMD1, ZYX class members Ajuba and WTIP also interact with PHD1/3 and VHL, and Ajuba confers enhanced HIF-la protein degradation. Preliminary evidence suggests Zyxin, TRIP6 and LPP, also members of the ZYX class, act as positive regulators of HIF-l, enhancing HIF-la protein stability and HIF-l transcriptional activity. This thesis therefore identifies LlMDl and implicates the ZYX class of LlM domain proteins as a unique family of protein regulators of HIF-l and the hypoxic response.
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Medves, Sandrine. "Effets de Tes (Testine), une protéine à domaine LIM, sur la structure et la dynamique du cytosquelette d'actine." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13174.
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Tränka, Christopher [Verfasser], Elke [Gutachter] Butt, and Ralf [Gutachter] Bargou. "Untersuchungen zur Expression und Funktion des „LIM and SH3 Domain Proteins“ (LASP-1) in Medulloblastomen / Christopher Tränka ; Gutachter: Elke Butt, Ralf Bargou." Würzburg : Universität Würzburg, 2016. http://d-nb.info/1116363542/34.
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Tränka, Christopher [Verfasser], Elke Gutachter] Butt, and Ralf C. [Gutachter] [Bargou. "Untersuchungen zur Expression und Funktion des „LIM and SH3 Domain Proteins“ (LASP-1) in Medulloblastomen / Christopher Tränka ; Gutachter: Elke Butt, Ralf Bargou." Würzburg : Universität Würzburg, 2016. http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139539.
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Neghabian, Dariusch [Verfasser]. "Rolle des four and-a-half LIM domain 1 (FHL-1) Proteins bei der Entstehung der Rechtsherzhypertrophie im Mausmodell des pulmonalarteriellen bandings / Dariusch Neghabian." Gießen : Universitätsbibliothek, 2019. http://d-nb.info/120035253X/34.
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Bordel, Anne-Claire. "Les protéines à domaines LIM chez le protoplaste de tournesol (Helianthus annuus L.) : expression des gènes et cytolocalisation." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2000. http://tel.archives-ouvertes.fr/tel-00012190.
Full textAbstract:
Les protéines LIM constituent une famille de molécules régulatrices possédant dans leur séquence protéique un ou plusieurs motifs en doigts de zinc – les domaines LIM – dont la fonction principale est de diriger les interactions protéine-protéine. Les protéines LIM ont ainsi la capacité d'interagir avec de multiples partenaires protéiques, et participent à l'assemblage et au maintien de certains des complexes macromoléculaires présents au sein de la cellule. La plupart des protéines LIM ont été caractérisées dans les cellules animales, où elles sont impliquées dans l'organisation du cytosquelette d'actine, ainsi que dans la régulation de la transcription. A ce jour, seules quelques protéines LIM ont été décrites chez les végétaux. La fonction de ces protéines LIM végétales reste encore à identifier. Afin de préciser le rôle des protéines LIM chez le tournesol, nous avons choisi comme modèle expérimental le protoplaste d'hypocotyle de tournesol, en raison de la possibilité de moduler son développement en fonction des conditions de culture.Nous avons étudié l'expression des gènes LIM précédemment décrits chez le tournesol dans les protoplastes par RT-PCR. Nous avons détecté un transcrit pour le gène HaWLIM-1, mais pas pour les deux autres gènes HaPLIM-1 et HaPLIM-2. Des anticorps polyclonaux spécifiques de la protéine HaWLIM-1 reconnaissent en immunoblot deux polypeptides distincts, dont les masses moléculaires sont respectivement de 52 kDa et 78 kDa. Ces masses moléculaires sont nettement supérieures à la taille attendue pour la protéine HaWLIM-1. Ces résultats indiquent que la protéine n'est pas présente sous forme de monomères dans les protoplastes, mais qu'elle participe à la formation de complexes protéiques stables.
L'étude par immunocytologie de la localisation intracellulaire de la protéine HaWLIM-1 révèle que cette protéine est présente simultanément dans deux compartiments distincts : le noyau et le cytoplasme. Dans le noyau, elle s'accumule préférentiellement dans le nucléole, et pourrait jouer un rôle dans la régulation de la transcription des gènes des ARNr, ou dans l'assemblage des ribosomes. Dans le cytoplasme, différentes approches, incluant des expériences de double-marquage et de déstructuration de composants du cytosquelette, ont permis de mettre en évidence une très forte colocalisation de la protéine HaWLIM-1 avec les microtubules, ce qui suggère un rôle pour cette protéine dans l'organisation du cytosquelette.
Lors de la culture des protoplastes, le gène HaWLIM-1 s'exprime constamment, avec cependant des variations dans le niveau d'expression. Des expériences d'immunoblot utilisant les anticorps spécifiques de la protéine HaWLIM-1 indiquent que de nouveaux polypeptides, de masses moléculaires égales à 35 kDa, 42 kDa et 64 kDa, apparaissent au cours de la culture. Cette observation suggère que la protéine HaWLIM-1 possède la capacité de s'associer et de se dissocier avec de nouveaux complexes protéiques au cours du développement. La protéine HaWLIM-1 est associée aux microtubules pendant tous les stades de la division : elle est présente au niveau de la bande préprophasique à la fin de l'interphase, au niveau du fuseau mitotique pendant la mitose, et au niveau du phragmoplaste pendant la cytokinèse. Ces observations semblent indiquer que la protéine HaWLIM-1 occupe une fonction importante au niveau des microtubules.
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GASS, NATHALIE. "Etude de la fonction physiologique et moleculaire d'une proteine a domaines lim, haplim1, specifiquement exprimee dans le pollen." Université Louis Pasteur (Strasbourg) (1971-2008), 2000. http://www.theses.fr/2000STR13134.
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Le but de ce travail etait d'etudier la fonction physiologique et moleculaire de la proteine haplim-1 une proteine a domaines lim specifiquement exprimee dans le pollen de tournesol. La partie essentielle du projet a consiste a developper une approche nouvelle visant a inactiver selectivement la proteine haplim1 dans le pollen grace a l'expression in vivo de derives d'anticorps monoclonaux (anticorps a domaine unique ou dabs et regions variables des chaines lourde et legere reunies en chaine unique ou scfvs) reconnaissant specifiquement cette proteine. Nous avons construit les derives d'anticorps scfvs pour deux anticorps monoclonaux diriges contre la proteine haplim1. Ces derives reconnaissent specifiquement haplim1 in vitro, contrairement aux derives dabs qui reconnaissent une dizaine de proteines additionnelles dans un extrait total de proteines de pollen. L'expression de ces derives dans le pollen de plantes de tournesol transgeniques n'a pas ete possible du fait qu'aucune plante transgenique n'a pu etre regeneree. Nous avons pu montrer ensuite que la proteine haplim-1 est capable de se dimeriser et que ses deux domaines lim sont indispensables a cette dimerisation. Par deux approches differentes, nous avons egalement pu mettre en evidence que haplim1 s'associe a une proteine de 50 kda dont l'identite n'a pas pu etre determinee. Enfin nous avons montre que les angiospermes possedent plusieurs (trois ou quatre) proteines lim dont les genes sont interrompus par 4 introns (sauf un des genes d'arabidopsis qui n'a que deux introns). Les etudes d'expression indiquent que des proteines lim sont presentes dans tous les organes d'une plante. Le pollen possede des proteines lim distinctes de celles des autres organes. Le role de ces proteines est encore inconnu, mais il semble qu'elles soient impliquees dans plusieurs fonctions nucleaires et cytoplasmiques, dont notamment l'association de structures membranaires avec des elements du cytosquelette.
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Dietz, Carola. "Expression der Tyrosinkinase Focal Adhesion Kinase (FAK) und des Four and a Half LIM Domain 2 Proteins (FHL2) im Zervixkarzinom und deren Korrelation mit klinischen Parametern /." Freiburg i.Br, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000254224.
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Pašalić, Zlatana. "The four and a half LIM domain protein 2 (FHL2) interacts with CALM and is highly expressed in acute myeloid leukemia (AML) with complex aberrant karyotypes." kostenfrei, 2008. http://edoc.ub.uni-muenchen.de/10582/.
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Pasalic, Zlatana. "The four and a half LIM domain protein 2 (FHL2) interacts with CALM and is highly expressed in acute myeloid leukemia (AML) with complex aberrant karyotypes." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-105825.
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Schnittger, Josef [Verfasser]. "Characterization of a novel interaction between four-and-a-half-LIM domains 2 and cardiomyopathy-associated protein 5 in cardiac myocytes / Josef Schnittger." Hamburg : Staats- und Universitätsbibliothek Hamburg Carl von Ossietzky, 2019. http://nbn-resolving.de/urn:nbn:de:gbv:18-ediss-87981.
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Tholl, Stéphane. "Etude biochimique comparative des "Actin Depolymerizing Factors"(ADFs) d'Arabidopsis : activité inattendue de pontage des filaments d'actine pour les ADFs appartenant à la sous-classe III." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAJ002.
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L'organisation et la dynamique du cytosquelette d'actine sont finement régulées par une multitude de "actin-binding proteins" (ABPs). Parmi ces dernières, les ADFs (actin-depolymerizing factors) jouent un rôle majeur dans le turnover des filaments d'actine en induisant leur découpage et en facilitant leur dépolymérisation. Arabidopsis thaliana possède 11 protéines ADFs fonctionnelles qui peuvent être classées en 4 sous-classes sur la base de leur profil d'expression et liens phylogénétiques. Nous démontrons que l’ADF5 et l’ADF9 de la sous-classe III sont des ADFs atypiques puisqu’elles n’induisent pas la dépolymérisation des filaments d’actine. Au contraire, elles montrent une forte capacité à stabiliser et ponter les filaments d’actine en longs câbles in vitro ainsi que in vivo. Nous décrivons la caractérisation d’un nouveau mutant knockout d’Arabidopsis. Les données suggèrent un rôle d’ADF9 dans l’élongation cellulaire. Ainsi, l’hypocotyle est significativement plus long dans les mutants adf9 que dans les plantules sauvages, et ce phénotype est amplifié par des conditions de croissance à l’obscurité dans lesquelles le gène ADF9 est normalement préférentiellement exprimé. L’analyse des cellules épidermiques d’hypocotyle indique que ce phénotype est essentiellement dut à une augmentation de l’élongation cellulaire. De manière surprenante, les plantules mutantes adf9 présentent également des racines plus courtes que les contrôles, suggérant un lien complexe entre l’organisation du cytosquelette d’actine et l’élongation cellulaire. Finalement, la capacité réduite du cal issue des plantules adf9 à proliférer suggère également un rôle d’ADF9 dans la division cellulaireActin cytoskeleton organization and dynamics are tightly regulated by many actin-binding proteins (ABPs). Among ABPs, the actin-depolymerizing factors (ADFs) play a major role in actin filament turnover by promoting actin filament severing and facilitating pointed end depolymerization. Arabidopsis thaliana has 11 functional proteins that can be classified into four subclasses according to their expression profile and phylogenetic relationships. We provide evidence that subclass III ADF5 and ADF9 are unconventional ADFs since they do not display typical actin filament depolymerizing activities. Instead, they exhibit opposite activities with a surprisingly high ability to stabilize and crosslink actin filaments into long and thick actin bundles both in vitro and in live cells. Competition experiments with ADF1 support that ADF9 antagonizes the depolymerizing activity of conventional ADFs. We report the characterization of a not yet described knockout Arabidopsis mutant. Data strongly suggests a role for ADF9 in cell elongation. Indeed, hypocotyls are significantly longer in adf9 mutant than in wild- type seedlings, and this phenotype is enhanced in dark growth conditions in which the ADF9 gene is normally preferentially expressed. The analysis of hypocotyl epidermal cells indicates that this phenotype is essentially due to an increase of cell expansion. Surprisingly, adf9 seedlings exhibit shorter roots than control plants, suggesting a complex link between actin cytoskeleton organization and cell elongation. Finally, the reduced ability of adf9- derived calli to proliferate supports a role for ADF9 in cell division as well
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Gupta, Shuchi [Verfasser], and Bernhard [Akademischer Betreuer] Nieswandt. "The role of the Canonical transient receptor potential 6 (TRPC6) channel and the C terminal LIM domain protein of 36 kDa (CLP36) for platelet function / Shuchi Gupta. Betreuer: Bernhard Nieswandt." Würzburg : Universitätsbibliothek der Universität Würzburg, 2013. http://d-nb.info/1043906622/34.
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BALTZ, RACHEL. "Etude structurale et fonctionnelle d'une proteine specifique de pollen a domaines lim et de son gene chez le tournesol (helianthus annuus l. )." Université Louis Pasteur (Strasbourg) (1971-2008), 1994. http://www.theses.fr/1994STR13178.
Full textAbstract:
Un adnc de 912 nucleotides, specifique du pollen de tournesol, code pour une proteine nommee plim-1 contenant deux domaines lim (regions riches en cysteine et histidine pouvant s'organiser sous forme de doubles doigts de zinc). Cette proteine possede, en plus, deux domaines basiques, un motif de 5 acides amines (a/t/s, d/e, tqn) repete six fois a l'extremite c-terminale et plusieurs sites potentiels de phosphorylation. Un clone d'adnc specifique d'ovaire codant pour une proteine olim-1 montre les memes caracteristiques, excepte le fait que le motif pentapeptidique c-terminal n'est pas present. Le gene sf3, codant pour plim-1, comporte 4 introns courts et est present au moins en dix copies dans le genome de tournesol. Les 224 nucleotides en amont du debut de transcription sont capables de diriger l'expression d'un gene reporter dans le pollen de tabac et constituent un promoteur fort specifique de pollen. Divers mutants de la proteine ont ete exprimes dans e. Coli et ont montre qu'elle est capable d'interagir avec l'adn. Des anticorps anti-plim-1 polyclonaux ont ete produits et utilises pour mettre en evidence la proteine dans des extraits proteiques de pollen et de fleurs. L'expression d'arn antisens sf3 et la surexpression de l'arn sf3 dans des plantes transgeniques de tabac et d'arabidopsis grace aux promoteurs de pollen des genes sf3 et lat52 (isole chez la tomate), ont conduit a une alteration importante du developpement du pollen conduisant a sa mort chez de nombreuses plantes transgeniques
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Sklar, Alexander Gabriel. "Channel Modeling Applied to Robust Automatic Speech Recognition." Scholarly Repository, 2007. http://scholarlyrepository.miami.edu/oa_theses/87.
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In automatic speech recognition systems (ASRs), training is a critical phase to the system?s success. Communication media, either analog (such as analog landline phones) or digital (VoIP) distort the speaker?s speech signal often in very complex ways: linear distortion occurs in all channels, either in the magnitude or phase spectrum. Non-linear but time-invariant distortion will always appear in all real systems. In digital systems we also have network effects which will produce packet losses and delays and repeated packets. Finally, one cannot really assert what path a signal will take, and so having error or distortion in between is almost a certainty. The channel introduces an acoustical mismatch between the speaker's signal and the trained data in the ASR, which results in poor recognition performance. The approach so far, has been to try to undo the havoc produced by the channels, i.e. compensate for the channel's behavior. In this thesis, we try to characterize the effects of different transmission media and use that as an inexpensive and repeatable way to train ASR systems.
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Gole, Shirish Gajanan. "Understanding the Role of Lsm Domain in Translation Repression Activity of RGG-motif Containing Protein Scd6." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/4286.
Full textAbstract:
Control of gene expression in eukaryotes is regulated at various steps such as transcription, translation and protein degradation. Translation repression of mRNA regulates protein levels and maintains cell homeostasis. Translation control allows for spatiotemporal regulation of gene expression which is required for development and differentiation in organisms. Deregulation of translation can result in disease conditions like cancer and neurodegenerative diseases. In yeast Saccharomyces cerevisiae, the RGG-motif protein Scd6 (Suppressor of Clathrin Deficiency 6) represses translation by binding eIF4G1 via its RGG domain and prevents formation of 48S pre-initiation complex. Scd6 consists of N-terminal Lsm domain, central FDF domain and C-terminal RGG domain.
In this study, we assessed the contribution of other domains of Scd6 in its translation repression ability. Overexpression of Scd6 causes growth defect as a result of global translation repression. We observed that overexpression of Lsm domain deletion mutant could partially rescue the growth defect phenotype suggesting that Lsm domain might be contributing in Scd6 mediated translation repression. Deletion of FDF domain did not result in any significant change in the growth defect phenotype of Scd6 overexpression. Interestingly, both Lsm and RGG domains are necessary but insufficient to repress translation on their own. Lsm domains are conserved RNA binding domains. By mutating the putative RNA binding motif within the Lsm domain we observed a rescue from the growth defect phenotype of Scd6. Also, our preliminary results indicate that the RNA binding motif mutant of Lsm domain is defective in binding poly(U) RNA. We analyzed the translation repression ability of Lsm domain mutants by observing RNA granule formation under stress and non-stress conditions. We observe that the mutants are defective in localizing to granules. In addition, the mutant containing only Lsm domain localizes to nucleus like structure in non-stress condition and forms fewer RNA granules in the cytoplasm upon stress. Since Scd6 binds eIF4G1 to repress translation we analyzed the ability of Lsm domain lacking Scd6 mutant to interact with eIF4G1 in vivo. Our preliminary observations suggest that Scd6 mutant lacking Lsm domain is deficient in binding eIF4G1 in vivo. Considering all the observations from our studies, we propose a model in which Lsm domain of Scd6 helps in recognition of the mRNA target of Scd6 which is followed by eIF4G1-RGG domain interaction leading to translation repression.