Littérature scientifique sur le sujet « Oriented cell division »
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Articles de revues sur le sujet "Oriented cell division"
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Strutt, David. « Organ Shape : Controlling Oriented Cell Division ». Current Biology 15, no 18 (septembre 2005) : R758—R759. http://dx.doi.org/10.1016/j.cub.2005.08.053.
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Castanon, I., et M. González-Gaitán. « Oriented cell division in vertebrate embryogenesis ». Current Opinion in Cell Biology 23, no 6 (décembre 2011) : 697–704. http://dx.doi.org/10.1016/j.ceb.2011.09.009.
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Dewey, Evan, Danielle Taylor et Christopher Johnston. « Cell Fate Decision Making through Oriented Cell Division ». Journal of Developmental Biology 3, no 4 (14 décembre 2015) : 129–57. http://dx.doi.org/10.3390/jdb3040129.
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Hart, Kevin C., Jiongyi Tan, Kathleen A. Siemers, Joo Yong Sim, Beth L. Pruitt, W. James Nelson et Martijn Gloerich. « E-cadherin and LGN align epithelial cell divisions with tissue tension independently of cell shape ». Proceedings of the National Academy of Sciences 114, no 29 (3 juillet 2017) : E5845—E5853. http://dx.doi.org/10.1073/pnas.1701703114.
Texte intégralRésumé :
Tissue morphogenesis requires the coordinated regulation of cellular behavior, which includes the orientation of cell division that defines the position of daughter cells in the tissue. Cell division orientation is instructed by biochemical and mechanical signals from the local tissue environment, but how those signals control mitotic spindle orientation is not fully understood. Here, we tested how mechanical tension across an epithelial monolayer is sensed to orient cell divisions. Tension across Madin–Darby canine kidney cell monolayers was increased by a low level of uniaxial stretch, which oriented cell divisions with the stretch axis irrespective of the orientation of the cell long axis. We demonstrate that stretch-induced division orientation required mechanotransduction through E-cadherin cell–cell adhesions. Increased tension on the E-cadherin complex promoted the junctional recruitment of the protein LGN, a core component of the spindle orientation machinery that binds the cytosolic tail of E-cadherin. Consequently, uniaxial stretch triggered a polarized cortical distribution of LGN. Selective disruption of trans engagement of E-cadherin in an otherwise cohesive cell monolayer, or loss of LGN expression, resulted in randomly oriented cell divisions in the presence of uniaxial stretch. Our findings indicate that E-cadherin plays a key role in sensing polarized tensile forces across the tissue and transducing this information to the spindle orientation machinery to align cell divisions.
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de Keijzer, Jeroen, Alejandra Freire Rios et Viola Willemsen. « Physcomitrium patens : A Single Model to Study Oriented Cell Divisions in 1D to 3D Patterning ». International Journal of Molecular Sciences 22, no 5 (5 mars 2021) : 2626. http://dx.doi.org/10.3390/ijms22052626.
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Development in multicellular organisms relies on cell proliferation and specialization. In plants, both these processes critically depend on the spatial organization of cells within a tissue. Owing to an absence of significant cellular migration, the relative position of plant cells is virtually made permanent at the moment of division. Therefore, in numerous plant developmental contexts, the (divergent) developmental trajectories of daughter cells are dependent on division plane positioning in the parental cell. Prior to and throughout division, specific cellular processes inform, establish and execute division plane control. For studying these facets of division plane control, the moss Physcomitrium (Physcomitrella) patens has emerged as a suitable model system. Developmental progression in this organism starts out simple and transitions towards a body plan with a three-dimensional structure. The transition is accompanied by a series of divisions where cell fate transitions and division plane positioning go hand in hand. These divisions are experimentally highly tractable and accessible. In this review, we will highlight recently uncovered mechanisms, including polarity protein complexes and cytoskeletal structures, and transcriptional regulators, that are required for 1D to 3D body plan formation.
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Wyatt, Tom P. J., Andrew R. Harris, Maxine Lam, Qian Cheng, Julien Bellis, Andrea Dimitracopoulos, Alexandre J. Kabla, Guillaume T. Charras et Buzz Baum. « Emergence of homeostatic epithelial packing and stress dissipation through divisions oriented along the long cell axis ». Proceedings of the National Academy of Sciences 112, no 18 (23 avril 2015) : 5726–31. http://dx.doi.org/10.1073/pnas.1420585112.
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Cell division plays an important role in animal tissue morphogenesis, which depends, critically, on the orientation of divisions. In isolated adherent cells, the orientation of mitotic spindles is sensitive to interphase cell shape and the direction of extrinsic mechanical forces. In epithelia, the relative importance of these two factors is challenging to assess. To do this, we used suspended monolayers devoid of ECM, where divisions become oriented following a stretch, allowing the regulation and function of epithelial division orientation in stress relaxation to be characterized. Using this system, we found that divisions align better with the long, interphase cell axis than with the monolayer stress axis. Nevertheless, because the application of stretch induces a global realignment of interphase long axes along the direction of extension, this is sufficient to bias the orientation of divisions in the direction of stretch. Each division redistributes the mother cell mass along the axis of division. Thus, the global bias in division orientation enables cells to act collectively to redistribute mass along the axis of stretch, helping to return the monolayer to its resting state. Further, this behavior could be quantitatively reproduced using a model designed to assess the impact of autonomous changes in mitotic cell mechanics within a stretched monolayer. In summary, the propensity of cells to divide along their long axis preserves epithelial homeostasis by facilitating both stress relaxation and isotropic growth without the need for cells to read or transduce mechanical signals.
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Moyle, Louise A., Richard Y. Cheng, Haijiao Liu, Sadegh Davoudi, Silvia A. Ferreira, Aliyah A. Nissar, Yu Sun, Eileen Gentleman, Craig A. Simmons et Penney M. Gilbert. « Three-dimensional niche stiffness synergizes with Wnt7a to modulate the extent of satellite cell symmetric self-renewal divisions ». Molecular Biology of the Cell 31, no 16 (21 juillet 2020) : 1703–13. http://dx.doi.org/10.1091/mbc.e20-01-0078.
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The skeletal muscle stem cell niche transiently stiffens during the tissue repair process, which serves to increase planar-oriented divisions and, when combined with WNT7a, induces symmetric cell division to expand the stem cell pool.
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Scepanovic, Gordana, et Rodrigo Fernandez-Gonzalez. « Oriented Cell Division : The Pull of the Pole ». Developmental Cell 47, no 6 (décembre 2018) : 686–87. http://dx.doi.org/10.1016/j.devcel.2018.11.040.
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Walker, Keely L., et Laurie G. Smith. « Investigation of the role of cell-cell interactions in division plane determination during maize leaf development through mosaic analysis of the tangled mutation ». Development 129, no 13 (1 juillet 2002) : 3219–26. http://dx.doi.org/10.1242/dev.129.13.3219.
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Most plant cells divide in planes that can be predicted from their shapes according to simple geometrical rules, but the division planes of some cells appear to be influenced by extracellular cues. In the maize leaf, some cells divide in orientations not predicted by their shapes, raising the possibility that cell-cell communication plays a role in division plane determination in this tissue. We investigated this possibility through mosaic analysis of the tangled (tan) mutation, which causes a high frequency of cells in all tissue layers to divide in abnormal orientations. Clonal sectors of tan mutant tissue marked by a closely linked albino mutation were examined to determine the phenotypes of cells near sector boundaries. We found that tan mutant cells always showed the mutant phenotype regardless of their proximity to wild-type cells, demonstrating that the wild-type Tan gene acts cell-autonomously in both lateral and transverse leaf dimensions to promote normally oriented divisions. However, if the normal division planes of wild-type cells depend on cell-cell communication involving the products of genes other than Tan, then aberrantly dividing tan mutant cells might send abnormal signals that alter the division planes of neighboring cells. The cell-autonomy of the tan mutation allowed us to investigate this possibility by examining wild-type cells near the boundaries of tan mutant sectors for evidence of aberrantly oriented divisions. We found that wild-type cells near tan mutant cells did not divide differently from other wild-type cells. These observations argue against the idea that the division planes of proliferatively dividing maize leaf epidermal cells are governed by short-range communication with their nearest neighbors.
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Concha, M. L., et R. J. Adams. « Oriented cell divisions and cellular morphogenesis in the zebrafish gastrula and neurula : a time-lapse analysis ». Development 125, no 6 (15 mars 1998) : 983–94. http://dx.doi.org/10.1242/dev.125.6.983.
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We have taken advantage of the optical transparency of zebrafish embryos to investigate the patterns of cell division, movement and shape during early stages of development of the central nervous system. The surface-most epiblast cells of gastrula and neurula stage embryos were imaged and analysed using a computer-based, time-lapse acquisition system attached to a differential interference contrast (DIC) microscope. We find that the onset of gastrulation is accompanied by major changes in cell behaviour. Cells collect into a cohesive sheet, apparently losing independent motility and integrating their behaviour to move coherently over the yolk in a direction that is the result of two influences: towards the vegetal pole in the movements of epiboly and towards the dorsal midline in convergent movements that strengthen throughout gastrulation. Coincidentally, the plane of cell division becomes aligned to the surface plane of the embryo and oriented in the anterior-posterior (AP) direction. These behaviours begin at the blastoderm margin and propagate in a gradient towards the animal pole. Later in gastrulation, cells undergo increasingly mediolateral-directed elongation and autonomous convergence movements towards the dorsal midline leading to an enormous extension of the neural axis. Around the equator and along the dorsal midline of the gastrula, persistent AP orientation of divisions suggests that a common mechanism may be involved but that neither oriented cell movements nor shape can account for this alignment. When the neural plate begins to differentiate, there is a gradual transition in the direction of cell division from AP to the mediolateral circumference (ML). ML divisions occur in both the ventral epidermis and dorsal neural plate. In the neural plate, ML becomes the predominant orientation of division during neural keel and nerve rod stages and, from late neural keel stage, divisions are concentrated at the dorsal midline and generate bilateral progeny (C. Papan and J. A. Campos-Ortega (1994) Roux's Arch. Dev. Biol. 203, 178–186). Coincidentally, cells on the ventral surface also orient their divisions in the ML direction, cleaving perpendicular to the direction in which they are elongated. The ML alignment of epidermal divisions is well correlated with cell shape but ML divisions within the neuroepithelium appear to be better correlated with changes in tissue morphology associated with neurulation.
Thèses sur le sujet "Oriented cell division"
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Darby, Daniel. « A mechanism of oriented cell division underlying cardiac chamber expansion ». Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS666.
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La morphogenèse est un processus qui nécessite une régulation à plusieurs niveaux à la fois physique et génétique. Les perturbations de ce programme dans le contexte du cœur ont souvent des conséquences importantes sur l'organe, comme le prouve l’incidence de 1% des cardiopathies congénitales à la naissance. Les cardiopathies congénitales telles que les cardiomyopathies, affectent l’architecture du muscle cardiaque essentielle à sa fonction contractile. Les parois ventriculaires sont particulièrement importantes, à la fois pour définir la taille des lumières ventriculaires et pour établir une architecture de myofibre orientée, renforçant l’efficacité de la contraction. Des travaux antérieurs dans le laboratoire ont permis de mettre en évidence l’émergence de l’orientation du myocarde. L'analyse clonale a révélé que la croissance tissulaire orientée corrélait avec l'expansion des ventricules (Sigolène M. Meilhac et al., 2004) et préfigurait l’architecture des myofibres du cœur nouveau-né (Meilhac et al., 2003). L'analyse de l’architecture cellulaire a révélé une coordination locale des divisions cellulaires indiquant une orientation des divisions cellulaires (Le Garrec et al., 2013). Ces études suggèrent que la division cellulaire orientée joue un rôle important dans la formation du cœur. Cependant, les mécanismes par lesquels cela est régulé doivent encore être identifiés dans les ventricules embryonnaires. Dans ce projet, nous utilisons une combinaison d'approches transcriptomique, segmentation cellulaire 3D, traitements chimiques en culture d'embryons et interférence moléculaire pour, étudier un mécanisme de division cellulaire orientée. Par séquençage ARN des ventricules, nous avons identifié l’expression de composants de l’appareil NuMA: GPSM, de la voie de la polarité cellulaire planaire et de la voie de mécano-détection des intégrines, qui sont des voies candidates pour réguler l’orientation de la division cellulaire. En parallèle, nous avons voulu déterminer si les cellules des ventricules en expansion se comportaient conformément à la règle de Hertwig. Pour ce faire, nous avons mis en place une méthode d’imagerie de l’architecture cellulaire dans le cœur entier par transparisation CUBIC et microscopie tridimensionnelle à feuille de lumière. Nous avons également amorcé le développement d’une méthode automatique de segmentation pour quantifier les axes de division cellulaire dans les ventricules. En comparant l’axe d'élongation des cellules aux axes de division les outils et les approches décrite ci-dessus permettront de conclure s'il existe une coordination entre les deux. Pour analyser l'importance des contractions cardiaques sur la croissance orientée des ventricules, nous avons établi des conditions de culture d'embryons traités avec des perturbateurs pharmaceutiques de la contraction cardiaque. Les résultats préliminaires indiquent qu'une augmentation et une diminution du taux de contraction affectent la forme du cœur. Enfin, nous avons conçu des vecteurs pour cibler les trois voies mentionnées ci-dessus avec des protéines dominant négatives. Les résultats de cette recherche pourraient avoir des applications en ingénierie tissulaire pour la réparation du cœurThe development of the heart is an intricate process both physically and genetically which requires regulation on many levels. Perturbations of this cardiogenic programme often has potent consequence on the organ and this is evident from the 1% incidence in births which are affected by a congenital heart disease (CHD). CHDs, such as cardiomyopathies, affect the architecture of the cardiac muscle, which is vital to the heartsfunction. The shape of the ventricular walls is particularly important to their function in terms of both defining the shape of the ventricular chambers and in establishing an appropriate myofiber architecture for efficient contractions (Meilhac et al., 2003). Previous work in the lab has provided insight into how this is achieved in the ventricles. It was found, through clonal analysis, that oriented tissue growth underlies cardiac chamber expansion (Meilhac et al., 2004). Analysis of earlier stages of the embryonic heart found regional coordination of cell divisions which preconfigured the myofiber architecture of the adult heart (Le Garrec et al., 2013). These studies suggest that oriented cell division plays an important role in sculpting the heart. However a mechanism by which this is regulated has yet to be established in the expanding ventricular chambers. In this project we use a combination of transcriptomic analysis, 3D cell segmentation, embryo culture experiments and molecular interference to investigate a mechanism for oriented cell division. Using bulk RNAseq we identified the NuMA:GPSM apparatus, the Planar Cell Polarity pathway and the integrin mechano-sensing pathway as candidates for further analysis. In combination with the transcriptomic analysis we wanted to identify if cells in the expanding ventricles were behaving according to Hertwig’s rule. To do this we have established CUBIC clearing and three dimensional lightsheet microscopy along with an automatic cell segmentation method to quantify cell elongations in the cardiac chambers. By comparing the elongation ratio of the cell to the detected axes of division the tools and approaches described above will enable us to identify if coordination existed between the two and if this was regionally specific. To analyse the impact of cardiac contractions on oriented cell division we established embryo culture experiment conditions paired with pharmaceutical interference of contractions. Preliminary results indicate that both an increase and decrease of contraction rate affects the shape of the heart. Finally, we will target the three pathways mentioned above with dominant negative proteins in chimeric hearts to dissect the molecular pathways. The outcome of this research will have potential applications in tissue engineering therapies targeting the heart
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Gallini, S. « MOLECULAR CONTRIBUTION OF THE AURORA-A KINASE AND THE JUNCTIONAL PROTEIN AFADIN TO ORIENTED CELL DIVISIONS ». Doctoral thesis, Università degli Studi di Milano, 2016. http://hdl.handle.net/2434/354581.
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Correct spindle positioning is essential for tissue morphogenesis and homeostasis. The orientation of the mitotic spindle is determined by cortical force generators formed on NuMA:LGN:Gαi complexes, which anchor astral microtubules emanating from the spindle poles at specialized domains of the plasma membrane via direct interaction with the motor proteins Dynein/Dynactin. Cortical polarity cues and actin-associated proteins synergize with extrinsic signals (such as cell-to-cell and cell-to-extracellular matrix contacts) in recruiting NuMA:LGN:Gαi complexes at the cell cortex. In addition, spindle placement is coordinated with mitotic progression by mitotic kinases regulating the timely cortical recruitment of NuMA:LGN:Gαi above the spindle poles.
My PhD project focused on the study of the molecular mechanisms accounting for the spindle orientation functions of the Aurora-A kinase, the polarity protein Lgl2, and the junctional protein Afadin.
The Aurora-A kinase is known for being implicated in spindle alignment, however the molecular events underlying this function remain to date unclear. To study the spindle orientation functions of Aurora-A, I developed protocols for the partial inhibition of its activity in transformed and non-transformed cells in culture. Under these conditions, in metaphase NuMA and Dynactin accumulate abnormally at the spindle poles without reaching the cortex, while the cortical distribution of LGN remains unperturbed. Fluorescence Recovery After Photobleaching (FRAP) experiments conducted on GFP-NuMA revealed that Aurora-A governs the dynamic exchange between the cytoplasmic and the spindle-pole-localized pools of NuMA. Molecularly, Aurora-A phosphorylates directly the C-terminus of NuMA on three serine residues, among which Ser-1969 is the major determinant for the dynamic behaviour of NuMA at the spindle poles. Most interestingly, we identify a new microtubule-binding domain of NuMA, which does not overlap with the LGN-binding motif, thus suggesting that NuMA can associate concomitantly with LGN and microtubules. This finding indicates that the microtubule-binding activity of NuMA might contribute to anchor microtubule +TIPs at cortical sites with LGN. Collectively, my studies demonstrate that in metaphase the direct phosphorylation of NuMA by Aurora-A controls its cortical enrichment, and that this is the major event underlying the spindle orientation functions of Aurora-A in cultured cells. Phosphorylation of NuMA by Aurora-A does not affect its affinity for microtubules nor for LGN, but rather determines the mobility of the protein at the spindle-poles.
Biochemical studies suggested that Lgl2 can associate with LGN, hinting at a possible role of this protein in spindle orientation in mammalian system. On these premises, I found that depletion of Lgl2 misorients the spindle in HeLa cells plated on fibronectin. However, I could not reproduce the Lgl2:LGN interaction in vitro nor ex vivo. Interestingly, by immunoprecipitation experiments I detected an interaction between NuMA and Lgl2, which could explain the phenotype of spindle misorientation resulting from the silencing of Lgl2 in HeLa cells. Further studies will be required to gain a molecular understanding of the relevance Lgl2:NuMA interaction in oriented divisions.
Part of my PhD studies addressed the role of Afadin in spindle orientation; I demonstrated that Afadin is required for spindle positioning, and correct epithelial morphogenesis of Caco-2 three-dimensional cysts. At a molecular level, Afadin binds directly and concomitantly to F-actin and to LGN. Indeed, in mitotic HeLa cells, Afadin is required for cortical accumulation of LGN, NuMA and Dynein above the spindle poles, in a F-actin dependent manner. Collectively, these results uncovered a pivotal role of Afadin in governing the enrichment of LGN and NuMA at the lateral cortex of polarized epithelia. They also depict that Afadin as the first mechanical anchor between Dynein and cortical F-actin.
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Strauss, Bernhard. « Oriented cell divisions in the Xenopus blastula ». Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614211.
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Francou, Alexandre. « Epithelial properties of Second Heart Field cardiac progenitor cells ». Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4062.
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Une partie du cœur est formée à partir des cellules progénitrices du second champ cardiaque, qui permettent une élongation rapide du tube cardiaque. Des défauts dans le développement de ces cellules entrainent des malformations cardiaques congénitales. Ces cellules sont localisées dans le péricarde dorsal au sein du mésoderme pharyngé. Mon travail de thèse a permis de démontrer pour la première fois que ces cellules sont épithéliales et polarisées, et qu’elles forment des filopodes dynamiques du côté basal. La délétion du facteur de transcription Tbx1 perturbe la polarité des cellules et la formation des filopodes, et augmente le niveau de la protéine apicale aPKCζ. Le traitement avec un activateur de aPKCζ montre le lien entre l’intégrité épithéliale, la polarité et la formation des filopodes, et l’état progéniteur des cellules. J’ai également analysé la polarité planaire dans l’épithélium, et montrais que les cellules sont anisotropiques, étirées et allongées en direction du pole artériel. Cet étirement crée une tension orientée, révélée par une accumulation polarisée d’actomyosine, jouant le rôle de rétrocontrôle négatif. En absence d‘élongation du tube cardiaque cette tension orientée est absente. Nous avons identifié une région postérieure de l’épithélium où se trouvent une tension et une prolifération élevées, ainsi qu’une forte activité YAP/TAZ qui jouerait le rôle de relai entre tension et prolifération. La tension orientée oriente les divisions cellulaires et oriente ainsi la croissance du tissu, promouvant l’addition des cellules au pole artériel. La biomécanique des cellules du second champ cardiaque semble ainsi un moteur important pour l’élongation du cœurA major part of the heart is formed by progenitor cells called the second heart field, that contribute to rapid elongation of the heart tube. Defects in second heart field development leads to congenital heart malformations. Second heart field cells are localised in pharyngeal mesoderm in the dorsal pericardial wall. This study focuses on the epithelial properties of second heart field cells and first shows that these progenitors in the dorsal pericardial wall are epithelial and polarised, and form dynamic basal filopodia. Deletion of the transcription factor Tbx1 perturbs epithelial polarity and filopodia formation and upregulates the apical determinant aPKCζ. Treatment with an activator of aPKCζ reveals that epithelial integrity, polarity and basal filopodia are coupled to the progenitor status of second heart field cells. Next we evaluated planar polarity of second heart field cells in the dorsal pericardial wall. Cells are anisotropic, being stretched and elongated on an axis directed towards the arterial pole. This stretch results in oriented epithelial tension revealed by polarised actomyosin accumulation through a negative feedback loop. In the absence of cell addition to the cardiac poles oriented tension is absent. We identified a posterior region in the epithelium with high tension, elevated proliferation and a high level of active YAP/TAZ that may act as relay between tension and proliferation. Oriented tension orients the axis of cell division and the growth of the tissue on an axis toward the arterial pole, further promoting addition of the tissue to the pole. Biomechanical feedback may thus be an important driver of heart tube elongation
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Di, Pietro Maria Florencia. « Systematic assessment of the role of Dynein regulators in oriented cell divisions by live RNAi screen in a novel vertebrate model of spindle orientation ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066405/document.
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L'orientation du fuseau mitotique joue un rôle essentiel dans le choix du destin cellulaire et dans l'homéostasie des tissus. Dans certains contextes, l'orientation du fuseau est contrôlée par le complexe moléculaire LGN, dont la localisation sous-corticale détermine le site de recrutement du moteur dyneine, lequel exerce des forces sur les microtubules astraux pour orienter le fuseau. Chez les vertébrés la régulation moléculaire de ce processus est cependant peu caractérisée. Nous avons décidé de chercher de nouveaux régulateurs de l'orientation du fuseau chez les vertébrés. Avec cet objectif, j'ai développé un modèle d'orientation du fuseau spécifiquement contrôlé par le complexe LGN. Avec ce modèle, j'ai réalisé un crible RNAi en évaluant 110 candidats incluant des moteurs moléculaires pour leur fonction dans l'orientation du fuseau. Notamment, ce crible a révélé que les régulateurs de la dyneine sont inégalement requis pour orienter le fuseau. De plus, entre les sous-unités de la dynactine, j'ai trouvé que la protéine du capping de l'actine, CAPZ-B, est un régulateur majeur de l'orientation du fuseau. La caractérisation de la fonction de CAPZ-B in vitro a révélé que CAPZ-B contrôle l'orientation du fuseau en régulant les complexes dyneine et dynactine ainsi que la dynamique des microtubules du fuseau, indépendamment de son rôle comme modulateur de l'actine. Finalement, nous avons démontré que CAPZ-B régule l'orientation planaire du fuseau in vivo dans le neuroépithelium. Je pense que mes travaux vont contribuer à la compréhension de la fonction de la dyneine dans l'orientation du fuseau chez les vertébrés, ouvrant la voie pour de nouvelles recherches dans le domaineMitotic spindle orientation is involved in cell fate decisions, tissue homeostasis and morphogenesis. In many contexts, spindle orientation is controlled by the LGN molecular complex, whose subcortical localization determines the site of recruitment of the dynein motor which exerts forces on astral microtubules orienting the spindle. In vertebrates, there is missing information about the molecules regulating the formation of the complex and those working downstream of it. This prompted us to screen for new regulators of vertebrate spindle orientation. For this, I developed a novel model of spindle orientation specifically controlled by the LGN complex. Using this model, I performed a live siRNA screen testing 110 candidates including molecular motors for their function in spindle orientation. Remarkably, this screen revealed that specific dynein regulators contribute differentially to spindle orientation. Moreover, I found that an uncharacterized member of the dynactin complex, the actin capping protein CAPZ-B, is a strong regulator of spindle orientation. Analyses of CAPZ-B function in cultured cells showed that CAPZ-B regulates spindle orientation independently of its classical role in modulating actin dynamics. Instead, CAPZ-B controls spindle orientation by modulating the localization/activity of the dynein/dynactin complexes and the dynamics of spindle microtubules. Finally, we demonstrated that CAPZ-B regulates planar spindle orientation in vivo in the chick embryonic neuroepithelium. I expect that my work will contribute to the understanding of dynein function during vertebrate spindle orientation and will open the path for new investigations in the field
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Di, Pietro Maria Florencia. « Systematic assessment of the role of Dynein regulators in oriented cell divisions by live RNAi screen in a novel vertebrate model of spindle orientation ». Electronic Thesis or Diss., Paris 6, 2016. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2016PA066405.pdf.
Texte intégralRésumé :
L'orientation du fuseau mitotique joue un rôle essentiel dans le choix du destin cellulaire et dans l'homéostasie des tissus. Dans certains contextes, l'orientation du fuseau est contrôlée par le complexe moléculaire LGN, dont la localisation sous-corticale détermine le site de recrutement du moteur dyneine, lequel exerce des forces sur les microtubules astraux pour orienter le fuseau. Chez les vertébrés la régulation moléculaire de ce processus est cependant peu caractérisée. Nous avons décidé de chercher de nouveaux régulateurs de l'orientation du fuseau chez les vertébrés. Avec cet objectif, j'ai développé un modèle d'orientation du fuseau spécifiquement contrôlé par le complexe LGN. Avec ce modèle, j'ai réalisé un crible RNAi en évaluant 110 candidats incluant des moteurs moléculaires pour leur fonction dans l'orientation du fuseau. Notamment, ce crible a révélé que les régulateurs de la dyneine sont inégalement requis pour orienter le fuseau. De plus, entre les sous-unités de la dynactine, j'ai trouvé que la protéine du capping de l'actine, CAPZ-B, est un régulateur majeur de l'orientation du fuseau. La caractérisation de la fonction de CAPZ-B in vitro a révélé que CAPZ-B contrôle l'orientation du fuseau en régulant les complexes dyneine et dynactine ainsi que la dynamique des microtubules du fuseau, indépendamment de son rôle comme modulateur de l'actine. Finalement, nous avons démontré que CAPZ-B régule l'orientation planaire du fuseau in vivo dans le neuroépithelium. Je pense que mes travaux vont contribuer à la compréhension de la fonction de la dyneine dans l'orientation du fuseau chez les vertébrés, ouvrant la voie pour de nouvelles recherches dans le domaineMitotic spindle orientation is involved in cell fate decisions, tissue homeostasis and morphogenesis. In many contexts, spindle orientation is controlled by the LGN molecular complex, whose subcortical localization determines the site of recruitment of the dynein motor which exerts forces on astral microtubules orienting the spindle. In vertebrates, there is missing information about the molecules regulating the formation of the complex and those working downstream of it. This prompted us to screen for new regulators of vertebrate spindle orientation. For this, I developed a novel model of spindle orientation specifically controlled by the LGN complex. Using this model, I performed a live siRNA screen testing 110 candidates including molecular motors for their function in spindle orientation. Remarkably, this screen revealed that specific dynein regulators contribute differentially to spindle orientation. Moreover, I found that an uncharacterized member of the dynactin complex, the actin capping protein CAPZ-B, is a strong regulator of spindle orientation. Analyses of CAPZ-B function in cultured cells showed that CAPZ-B regulates spindle orientation independently of its classical role in modulating actin dynamics. Instead, CAPZ-B controls spindle orientation by modulating the localization/activity of the dynein/dynactin complexes and the dynamics of spindle microtubules. Finally, we demonstrated that CAPZ-B regulates planar spindle orientation in vivo in the chick embryonic neuroepithelium. I expect that my work will contribute to the understanding of dynein function during vertebrate spindle orientation and will open the path for new investigations in the field
Livres sur le sujet "Oriented cell division"
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Kühn, Wolfgang, et Gerd Walz. The molecular basis of ciliopathies and cyst formation. Sous la direction de Neil Turner. Oxford University Press, 2015. http://dx.doi.org/10.1093/med/9780199592548.003.0303.
Texte intégralRésumé :
Abnormalities of the cilium, termed ‘ciliopathies’, are the prime suspect in the pathogenesis of renal cyst formation because the gene products of cystic disease-causing genes localize to them, or near them. However, we only partially understand how cilia maintain the geometry of kidney tubules, and how abnormal cilia lead to renal cysts, and the diverse range of diseases attributed to them. Some non-cystic diseases share pathology of the same structures. Although still incompletely understood, cilia appear to orient cells in response to extracellular cues to maintain the overall geometry of a tissue, thereby intersecting with the planar cell polarity (PCP) pathway and the actin cytoskeleton. The PCP pathway controls two morphogenetic programmes, oriented cell division (OCD) and convergent extension (CE) through cell intercalation that both seem to play a critical role in cyst formation. The two-hit theory of cystogenesis, by which loss of the second normal allele causes tubular epithelial cells to form kidney cysts, has been largely borne out. Additional hits and influences may better explain the rate of cyst formation and inter-individual differences in disease progression. Ciliary defects appear to converge on overlapping signalling modules, including mammalian target of rapamycin and cAMP pathways, which can be targeted to treat human cystic kidney disease irrespective of the underlying gene mutation.
Chapitres de livres sur le sujet "Oriented cell division"
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Piano, Fabio, et Kenneth Kemphues. « Genetic analysis of intrinsically asymmetrical cell division ». Dans Cell Polarity, 240–68. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780199638031.003.0008.
Texte intégralRésumé :
Abstract Intrinsically asymmetrical cell division is a major mechanism for generating cell diversity. In this process, referred to simply as asymmetrical division in this chapter, cytoplasmic and cortical asymmetries within a mother cell combine with an oriented cell division to produce daughter cells with different cytoplasmic components and consequently different cell fates (1). As illustrated in Fig. 1, there are three processes that contribute to asymmetrical cell divisions: (1) establishment of polarity; (2) localization of determinants; (3) oriented cell division.
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Wolpert, Lewis, Cheryll Tickle, Alfonso Martinez Arias, Peter Lawrence et James Locke. « Plant development ». Dans Principles of Development. Oxford University Press, 2019. http://dx.doi.org/10.1093/hesc/9780198800569.003.0013.
Texte intégralRésumé :
This chapter explores the development of plants. It expounds on how a plant’s architecture is the result of patterns of oriented cell divisions with a combination of positional signals and intercellular communication. Moreover, the chapter discusses cytoplasmic channels interconnecting plant cells. It notes the regeneration of an isolated somatic cell, the presence of relatively rigid walls, and the absence of any cell migration as distinctive features of plant development. The chapter discusses the early stages of plant development, in which involving both asymmetric cell division and cell-cell interactions are involved in line with patterning the body plan and the specificity of the shoot and root meristems., Twhile these meristems give rise to all the organs of the plant: stems, leaves, flowers, and roots.
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León-Mejía, Grethel, Alvaro Miranda Guevara, Ornella Fiorillo Moreno et Carolina Uribe Cruz. « Cytotoxicity as a Fundamental Response to Xenobiotics ». Dans Cytotoxicity - New Insights into Toxic Assessment. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96239.
Texte intégralRésumé :
Cytotoxicity refers to the ability of a molecule or a compound to cause some type of cellular damage, of which some of the adverse effects that can occur include injuries to some structures or the fundamental processes involved in cell maintenance, such as survival, cell division, cell biochemistry, and the normal cell physiology. The potential for cytotoxicity is one of the first tests that must be performed to determine the effects of drugs, biomolecules, nanomaterials, medical devices, pesticides, heavy metals, and solvents, among others. This potential may be oriented in the mechanism under which it generates cell death, the dose, and the target cells that generate the response. The evaluation of the toxicologic and cytotoxic properties of the chemical substances through in vitro tests has become a competitive alternative to in vivo experimentation as a consequence of ethical considerations. Presently, there are numerous tests conducted to evaluate the cytotoxicity of a certain agent, the selection of which depends on the purpose of the study. In this sense, the present review provides a general overview of the different responses of a cell to xenobiotic agents and the different test that can be useful for evaluation of these responses.
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Pidoux, Alison L., et Robin C. Allshire. « The structure of yeast centromeres and telomeres and the role of silent heterochromatin ». Dans The Yeast Nucleus, 212–45. Oxford University PressOxford, 2000. http://dx.doi.org/10.1093/oso/9780199637737.003.0007.
Texte intégralRésumé :
Abstract Genome stability and accurate chromosome segregation are of paramount importance to the cell and to the organism. The consequences of mistakes in mitosis and meiosis are severe indeed. In unicellular eukaryotes, aneuploidy is often deleterious or even fatal. For complex eukaryotes, chromosome gain or loss events are a leading cause of genetic diseases, miscarriage, and birth defects, and contribute to the progression of cancer. Chromosome rearrangements and fusions resulting from free DNA ends (e.g. those lacking telomeres) may have profoundly deleterious effects. To ensure their structural integrity and successful transmission, chromosomes must have origin(s) of replication, a single functional centromere and, if linear, telomeres. The centromere was originally defined cytologically on mammalian chromosomes as the site of the primary constriction. Together with its associated proteinaceous kinetochore, this region of DNA is responsible for chromosome attachment to spindle microtubules and chromosome segregation at cell division (1). Centromcres perform very precise functions; during the S phase of the cell cycle, chromosomes are replicated, but the two chromatids must remain associated at their centromere until mitosis. At the onset of mitosis, sister kinetochores must specifically bind to microtubules emanating from the two opposite poles of the spindle. When all chromosomes are correctly attached and oriented on the metaphase plate, the sister chromatids part company and move to the spindle poles in anaphase, led by their kinetochores. In meiosis the situation is more complex.
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Davies, Jamie A. « Morphogenesis by Orientated Cell Division ». Dans Mechanisms of Morphogenesis, 307–23. Elsevier, 2013. http://dx.doi.org/10.1016/b978-0-12-391062-2.00023-1.
Texte intégral
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Davies, Jamie A. « Morphogenesis by Orientated Cell Division ». Dans Mechanisms of Morphogenesis, 361–77. Elsevier, 2023. http://dx.doi.org/10.1016/b978-0-323-99965-6.00002-6.
Texte intégral
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Carlos Valdés Hernández, Roberto, Juan Gabriel Lopez Hernandez, Adelaida Figueroa Villanueva et Vidblain Amaro Ortega. « Impact of ICT to Improve of the Manufacturing in a SME Biomedical of Mexicali, Mexico ». Dans Concepts, Applications and Emerging Opportunities in Industrial Engineering. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.93585.
Texte intégralRésumé :
This work presents a way to optimize the manufacturing processes in a small biomedical industry considered in the micro-, small-, and medium-sized enterprises (SME) group and located in the Mexicali city, using a specialized software that act as design and test of a new model, being the COSIMIR (Cell Oriented Simulation of Industrial Robots) software. With this software was designed a new industrial process in a workstation separated of the main step of a manufacturing line, where are fabricated biomechanical knees pads. The process was made as a manual activity in a work station and had to be separated from the conveyor belt of the main activities, because where previously made by an automatized device that was failing continually and was delaying the delivery to the next steps of the manufacturing processes and to the customers as a final product fabricated in this industry. In this place of the company, an operation was made to organize the biomechanical knee in a plastic container with divisions and to be transported safe and quickly to other area by a conveyor belt with linear process flow. The investigation was conducted from 2018 to 2019.
Actes de conférences sur le sujet "Oriented cell division"
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Hashimoto, Shigehiro, Hiroki Yonezawa et Ryuya Ono. « Cell Activity Change After Division Under Wall Shear Stress Field ». Dans ASME 2021 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/imece2021-69689.
Texte intégralRésumé :
Abstract Does cell orientation depend on the cell type in the shear stress field? Does that tendency change after the division? In this study, the behavior of each cell after division was tracked by time-lapse microscopic images through 24 hours of culture under a shear stress field. A constant shear stress field was applied to the cells in the Couette flow between the parallel walls: the lower static culture disc and the upper rotating disc. For comparison, four types of cells were used: C2C12 (mouse myoblast), HUVEC (human umbilical vein endothelial cells), 3T3-L1 (mouse adipose progenitor cells), and L929 (mouse fibroblast). The result is as follows. In the wall shear stress field of 1 Pa, HUVEC is oriented parallel to the flow, regardless of the division. In other cell types (C2C12, 3T3-L1, and L929) after division, the deformed cell tends to tilt to the direction parallel to the flow. The experimental results are expected to be applied to engineered tissue technologies.
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Hashimoto, Shigehiro, et Takashi Yokomizo. « Tracings of Interaction Between Myoblasts Under Shear Flow in Vitro ». Dans ASME 2021 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fedsm2021-65203.
Texte intégralRésumé :
Abstract How does the group of cells make orientation perpendicular to the flow direction? How does contact with an adjacent cell affect the orientation of the cell? The orientation of a cell according to the neighbor cell under shear flow fields has been traced in vitro. A Couette type flow device with parallel discs was manufactured for the cell culture under the controlled constant wall shear stress. Cells (C2C12: mouse myoblast cell line) were cultured on the lower disc while applying the shear flow in the medium by the upper rotating disc. After culture for 24 hours without flow for adhesion of cells, 2 Pa of the constant wall shear stress was continuously applied in the incubator for 7 days. The behavior of each cell was traced by time-lapse images observed by an inverted phase contrast microscope placed in an incubator. The experiment shows the following results quantitatively by parameters: the contact ratio, and the angle between major axes of cells approximated to ellipsoids. As the ratio of the contact length with the adjacent cell to the pericellular length increases in the two-dimensional projection images, the adjacent cells tend to be oriented in parallel with each other.
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Piqueras, Pedro, Benjamín Pla, Enrique José Sanchis et André Aronis. « Ammonia Slip Estimation Based on ASC Control-Oriented Modelling And OBD NOx Sensor Cross-Sensitivity Analysis ». Dans ASME 2021 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/icef2021-67710.
Texte intégralRésumé :
Abstract The incoming emission regulations for internal combustion engines are gradually introducing new pollutant species, which requires greater complexity of the exhaust gas aftertreatment systems concerning layout, control and diagnostics. This is the case of ammonia, which is already regulated in heavy-duty vehicles and to be included in the emissions standards applied to passenger cars. The ammonia is injected into the exhaust gas through urea injections for NOx abatement in selective catalytic reduction (SCR) systems and can be also generated in other aftertreatment systems as three-way catalysts. However, ammonia slip may require removal on a dedicated catalyst called ammonia slip catalyst (ASC). The set consisting of the urea injection system, SCR and ASC requires control and on-board diagnostic tools to ensure high NOx conversion efficiency and minimization of the ammonia slip under real driving conditions. These tasks are based on the use of NOx sensors ZrO2 pumping cell-based, which present as a drawback high cross-sensitivity to ammonia. Consequently, the presence of this species can affect the measurement of NOx and compromise SCR-ASC control strategies. In the present work, a methodology to predict ammonia and NOx tailpipe emissions is proposed. For this purpose, a control-oriented ASC model was developed to use its ammonia slip prediction to determine the cross-sensitivity correction of the NOx sensor placed downstream of the ASC. The model is based on a simplified solution of the transport equations of the species involved in the main ASC reactions. The ammonia slip model was calibrated using steady- and quasi-steady-state tests performed in a Euro 6c diesel engine. Finally, the performance of the proposed methodology to predict NOx and ammonia emissions was evaluated against experimental data corresponding to Worldwide harmonized Light vehicles Test Cycles (WLTC) applying different urea dosing strategies.
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Spring, Peter, Lino Guzzella et Christopher H. Onder. « Optimal Control Strategy for a Pressure-Wave Supercharged SI Engine ». Dans ASME 2003 Internal Combustion Engine Division Spring Technical Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ices2003-0645.
Texte intégralRésumé :
On the basis of a control-oriented mean-value model of a spark-ignition engine supercharged with a pressure-wave supercharger, this paper introduces an operation strategy which minimizes the torque response time to driver commands. Since in pressure-wave superchargers fresh air and exhaust gas are in direct contact in the cell wheel, unwanted and excessive exhaust gas recirculation over the pressure-wave supercharger has to be limited by appropriate control actions. The most critical situation arises when large amounts of exhaust gas are recirculated during a hard acceleration, which causes the engine torque to drop sharply and thus to severely affect driveability. In order to prevent such situations, a set of actuators (throttles, valves, etc.) has to be controlled in a coordinated way. Conventional strategies cause the actuators to be closed at a fairly slow, steady rate. Our investigations show that driveability can be improved with a somewhat more complex strategy.
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Moser, Sean, Simona Onori et Mark Hoffman. « Design and Experimental Validation of a Spatially Discretized, Control-Oriented Temperature Model for a Ceria-Washcoated Gasoline Particulate Filter ». Dans ASME 2018 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icef2018-9687.
Texte intégralRésumé :
Gasoline particulate filters (GPFs) are the most promising and practically applicable devices to reduce Particulate Matter (PM) and Particulate Number (PN) emissions from gasoline direct ignition engines. A model that can predict internal GPF temperature dynamics during regeneration events can then be implemented online to maintain GPF health and aide in exotherm control algorithms without the associated instrumentation costs. This work demonstrates a control-oriented model, which captures the thermal dynamics in a catalyzed, ceria-coated GPF in the axial direction. The model utilizes soot oxidation reaction kinetics to predict internal GPF temperature dynamics during regeneration events using three finite volume cells. A model methodology initially proposed by Arunachalam et al [18] is utilized with the GPF of this work, validating the broad applicability of that methodology. Then, the model’s temperature prediction fidelity is improved through axial discretization. The zonal model parameters are identified via a Particle Swarm Optimization using experimental results from the instrumented GPF. Identified parameters from the various data sets are used to develop a linear parameter varying model for prediction of the axial temperature distribution within the GPF. The resulting model is then validated against an experimental data set utilizing the exhaust temperature entering the GPF. The spatial discretization methodology employed both enables the prediction of spatial temperature variation within the GPF and improves the accuracy of the peak temperature prediction by a factor ranging from 2–10x.
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Rozenfeld, A., Y. Kozak, T. Rozenfeld et G. Ziskind. « A Novel Double-Pipe Heat Storage Unit ». Dans ASME 2016 Heat Transfer Summer Conference collocated with the ASME 2016 Fluids Engineering Division Summer Meeting and the ASME 2016 14th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/ht2016-7394.
Texte intégralRésumé :
This research is an experimental investigation of a double-pipe heat storage unit. The inner pipe of the unit, through which a heat-transfer fluid (HTF) is supplied, is made of aluminum and has an outer helix-like fin. The annular space between the pipes is filled with a phase change material (PCM). Actually, this research presents a novel design of the heat storage unit, which, unlike traditional designs with e.g. radial (circumferential) or longitudinal fins, has a single fin which does not divide the shell volume into separated cells. Moreover, this research focuses on close-contact melting (CCM), a process which is characterized by detachment of the solid bulk from the unit envelope and its sinking towards the hot fin surface. In previous investigations, performed in our laboratory, this effect has been achieved in units with above-mentioned traditional fin configurations. It was demonstrated that CCM reduces the overall melting time, i.e. the rate of unit charging, significantly as compared with commonly encountered melting in which the fins serve just to enlarge the heat transfer area. The experimental system employed in this study includes a vertically-oriented double-pipe heat storage unit and thermostatic baths capable of providing hot or cold HTF. The unit has a transparent Perspex shell which makes visualization possible. The entire unit may be placed in a heated water tank with transparent walls. In the latter case, close-contact melting is achieved by detaching the solid phase from the envelope and thus allowing its gravity-induced motion. Regular melting is compared to CCM and advantages of the latter are demonstrated. Also demonstrated are the advantages of the novel fin, including in solidification. Possible mathematical and numerical modeling of the melting processes is discussed.
Rapports d'organisations sur le sujet "Oriented cell division"
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Sadot, Einat, Christopher Staiger et Zvi Kam Weizmann. functional genomic screen for new plant cytoskeletal proteins and the determination of their role in actin mediated functions and guard cells regulation. United States Department of Agriculture, janvier 2003. http://dx.doi.org/10.32747/2003.7587725.bard.
Texte intégralRésumé :
The original objectives of the approved proposal were: 1. To construct a YFP fused Arabidopsis cDNA library in a mammalian expression vector. 2. To infect the library into a host fibroblast cell line and to screen for new cytoskeletal associated proteins using an automated microscope. 3. Isolate the new genes. 4. Characterize their role in plants. The project was approved as a feasibility study to allow proof of concept that would entail building the YFP library and picking up a couple of positive clones using the fluorescent screen. We report here on the construction of the YFP library, the development of the automatic microscope, the establishment of the screen and the isolation of positive clones that are plant cDNAs encoding cytoskeleton associated proteins. The rational underling a screen of plant library in fibroblasts is based on the high conservation of the cytoskeleton building blocks, actin and tubulin, between the two kingdoms (80-90% homology at the level of amino acids sequence). In addition, several publications demonstrated the recognition of mammalian cytoskeleton by plant cytoskeletal binding proteins and vice versa. The major achievements described here are: 1. The development of an automated microscope equipped with fast laser auto-focusing for high magnification and a software controlling 6 dimensions; X, Y position, auto focus, time, color, and the distribution and density of the fields acquired. This system is essential for the high throughput screen. 2. The construction of an extremely competent YFP library efficiently cloned (tens of thousands of clones collected, no empty vectors detected) with all inserts oriented 5't03'. These parameters render it well representative of the whole transcriptome and efficient in "in-frame" fusion to YFP. 3. The strategy developed for the screen allowing the isolation of individual positive cDNA clones following three rounds of microscopic scans. The major conclusion accomplished from the work described here is that the concept of using mammalian host cells for fishing new plant cytoskeletal proteins is feasible and that screening system developed is complete for addressing one of the major bottlenecks of the plant cytoskeleton field: the need for high throughput identification of functionally active cytoskeletal proteins. The new identified plant cytoskeletal proteins isolated in the pilot screen and additional new proteins which will be isolated in a comprehensive screen will shed light on cytoskeletal mediated processes playing a major role in cellular activities such as cell division, morphogenesis, and functioning such as chloroplast positioning, pollen tube and root hair elongation and the movement of guard cells. Therefore, in the long run the screen described here has clear agricultural implications.