Dissertations / Theses on the topic 'ST14'

Många företag och industrier arbetar idag ständigt med att utveckla mindre miljöbelastande sätt att arbeta på, det beror på hårdare lagar och regler än tidigare angående utsläpp till miljön. Företag inventerar mycket resurser på ny forskning och ta fram nya metoder, allt för att bidra till en hållbar utveckling. St1 är ett av de företagen som vill vara med i arbetet för en hållbar utveckling och främst av förnybara bränslen. St1 har utvecklat en ny metod för framställning av etanol utav restråvaror från livsmedelsindustrin. Det bildas även drank som är en biprodukt som man kör ut till lantbruk för att använda som djurfoder eller vid produktion av biogas. Metoden benämns som Etanolix och den nya anläggningen på St1 Refinery AB är den senaste som fått namnet Etanolix 2.0. Syftet med rapporten är att visa hur integrering kan göras med en ny anläggning tillsammas med en redan befintlig och hur man kan ta till vara på outnyttjade resurser. I rapporten beskrivs de olika hjälpsystem som är integrerade med Etanolix 2.0 som processvatten, kvävgas samt ånga och kondensat. Det beskrivs också hur första året med Etanolix 2.0 i drift har gått och vad som varit utmaningarna vid uppstarten. Slutsatsen vi kom fram till är att Etanolix metoden bidrar till en hållbar utveckling och steget närmare att skapa framtida förnybara bränslen. Projekt Etanolix 2.0 är fortfarande i uppstartningsfasen och behöver ytterligare utveckling innan optimal produktion av etanol kan ske.

Vatten är en viktig komponent för alla oljeraffinaderier, både för kylning och för själva destillationsprocessen. Vatten som har kommit i kontakt med olja, sulfider, kväveföreningar samt andra miljöfarliga ämnen, kallas processvatten och måste renas innan det släpps ut i recipient. Processvattnet renas i vattenreningsverk som kan se olika ut och ha olika uppbyggnad.St1 Refinery AB ligger på Hisingen i Göteborg vid Göta älv och har ett biologiskt vattenreningsverk som kallas Biotreatern. Biotreatern har i uppgift att rena processvattnet främst ifrån kväveföreningar, men även olja och andra miljöfarliga ämnen med hjälp av bakterier. Biotreatern har problem med så kallat slamflykt, detta kan påverka att utsläppskrav för bl.a. mängden olja och kväveföreningar i renat vatten överskrids. Om utsläppskraven överskrids kan detta leda till höga bötersbelopp för företaget och en ökad negativ påverkan på miljön. Syftet med rapporten är att ta fram förslag på förbättringar och nya tekniska lösningar till Biotreatern för att minska slamflykten. I rapporten redovisas resultat som främst handlar om nya filtreringstekniker, hur dessa fungerar och var i anläggningen de kan appliceras för att undvika slamflykt. Vilka huvudsakliga faktorer som styr reningsprocessen och vad begreppet slamflykt innebär, beskrivs i rapporten. Det beskrivs också hur reningsprocessen fungerar, tillsammans med uppritat flödesschema över anläggningen. De förbättringsförslag som presenteras i rapporten, kan minska och eventuellt eliminera problemet med slamflykt som Biotreatern lider av idag.

Os gliomas são os tumores mais fatais do sistema nervoso central, para os quais ainda não há tratamento eficaz. Para analisar as bases celulares e moleculares da ação do agente diferenciador e antitumoral ácido retinóico (ATRA) sobre gliomas, foi utilizado, como modelo, a linhagem STl de glioma de rato. Propôs-se: a) analisar os efeitos de ATRA sobre a morfologia, proliferação e morte celular; b) isolar, identificar e caracterizar genes induzidos por ATRA em células STl. Verificou-se que o tratamento com ATRA promove achatamento celular e inibição da síntese de DNA e do crescimento em suspensão de agarose, caracterizando uma completa reversão fenotípica tumoral-normal, a qual não é acompanhada de indução de apoptose. Os genes induzidos por ATRA foram isolados através da construção de bibliotecas subtraídas de cDNA por: RDA (\"Representational Diference Analysis\") e SSH (\"Suppressive Subtractive Hybridization\") acoplados a rastreamento em \"macroarrays\". Foram identificados 10 genes regulados por ATRA durante a reversão fenotípica das células STl: p450rai2, spi3, vegf, cdv-3a, okl38, eya2, gem, retSDR1, aldose redutase-like, e um gene novo, com 61 % de identidade com uma fosfatase de galinha. Este estudo permitiu a caracterização dos efeitos de ATRA sobre STl e identificou novos alvos para futuro desenvolvimento de novas drogas e terapia gênica.
Gliomas are the most fatal central nervous system tumors, for which efficient treatment is still not available. To analyze the cellular and molecular bases for the action of the differentiating and anti-tumor agent retinoic acid (ATRA) in gliomas, the rat glioma STl cell line was used as a model. We proposed: a) to analyze the effects of ATRA in STl cells morphology, growth and apoptosis; b) to isolate, identify and characterize the ATRA-induced genes in STl cells. We demonstrated that ATRA promotes cellular flattening and inhibition of DNA synthesis and growth in agarose suspension, characterizing a complete tumoral to normal phenotypic reversion, which is not accompanied by apoptosis. Subtracted cDNA libraries were generated, using 2 different methodologies: RDA (Representational Difference Analysis) and SSH (Suppressive Subtractive Hybridization) followed by macroarray screening. This allowed identification of 10 ATRA induced genes which are up regulated by ATRA during STl cells phenotypic reversion, namely: p450rai2, spi3, vegf, cdv-3a, okl38, eya2, gem, retSDR1, aldose redutase-like and a new gene with 61 % identity with chicken phosphatase. This study characterized the cellular and molecular effects of ATRA upon STl cells and allowed identification of new targets for future development of new drugs and gene therapy.

Legionella pneumophila (Lp) est un pathogène accidentel de l'homme capable d'infecter les macrophages alvéolaires et les pneumocytes. Au cours de l'infection, Legionella se confronte à différents types d'agents antibactériens, dont les peptides antimicrobiens (PAMs) produit par l'hôte et les antibiotiques à activité intracellulaire administrés aux patients. Le mécanisme d'action des PAMs humains à l'encontre de Legionella, ainsi que le niveau de résistance aux antibiotiques de la bactérie sont à ce jour encore peu documentés. Mes travaux ont pour but de contribuer à une meilleure connaissance de l'activité anti-Legionella de ces molécules. La première partie de cette étude a consisté à évaluer la sensibilité d'isolats cliniques de Lp sg 1 à 8 antibiotiques, afin de déterminer le seuil épidémiologique de sensibilité de la bactérie à ces différentes molécules. Nous avons démontré que l'ensemble des isolats cliniques sont sensibles aux antibiotiques testés. Les résultats ont révélé l'existence d'une sous-population présentant une sensibilité réduite aux macrolides. L'analyse des génomes a permis de corréler cette sensibilité diminuée à la présence de la pompe à efflux LpeAB spécifique des macrolides. Cette pompe est présente uniquement dans trois complexes clonaux centrés sur le ST1, le ST701 et le ST1335.La seconde partie de cette étude a été consacrée à la caractérisation de l'activité antibactérienne des PAMs humains LL-37 et HBD-3, ainsi qu'à l'identification de leur(s) mécanisme(s) d'action contre Legionella. L'ensemble des tests réalisés montre que LL-37 et HBD-3 induisent une perte de cultivabilité des légionelles par des modes d'action différents. Les résultats suggèrent que LL-37 agit par perméabilisation des membranes de L. pneumophila. Nos résultats ont également montré que les deux peptides exercent une activité inhibitrice sur la réplication intracellulaire des légionelles, au moins en partie grâce à une collaboration avec la cellule hôte
Legionella pneumophila (Lp) is an accidental human pathogen which can infect alveolar macrophages and pneumocytes. During infection, Legionella have to deal with to various types of antibacterial agents, such as antimicrobial peptides (AMPs) produced by the host, and antibiotics with intracellular activity administered to patients. The mechanism of action of human AMPs against Legionella, and the resistance level to antibiotics of the bacterium are still poorly described. Our work aimed to contribute to a better understanding of the anti-Legionella activity of these molecules. The first part of this study consisted in the evaluation of the susceptibility of clinical Lp sg1 isolates to 8 antibiotics, to determine the epidemiological cut-off values of these different molecules. We demonstrated that all clinical isolates are susceptible to the tested antibiotics. The results revealed the presence of a subpopulation displaying a reduced susceptibility to macrolides. The analysis of the genomes allowed us to correlate this reduced susceptibility to le presence of the LpeAB macrolides efflux pump, found specifically in the sequence types ST1, ST701 and ST1335.The second part of this study was dedicated to the characterization of the antibacterial activity of the human AMPs LL-37 and HBD-3, and to the identification of their mechanism(s) of action against Legionella. All of the experiments show that LL-37 and HBD-3 induce a loss of cultivability by different mode of action. The results suggest that LL-37 is able to permeabilize the membrane of the L. pneumophila cells. Our findings also show that both peptides inhibit the intracellular replication of L. pneumophila, in part through collaboration with the host cell

Os hormônios glicocorticóides (GCs) têm sido amplamente empregados como agentes antiinflamatórios e anti-tumorais. Sua ação ocorre via receptores nucleares (GR) sendo dependente da remodelação da estrutura da cromatina. As proteínas Brm e BRG1, componentes essenciais de um complexo regulador global da transcrição (SWI/SNF), por remodelamento da cromatina, exercem um papel-chave na ação de GR. Para estudar o mecanismo de ação de GCs, foram utilizadas as linhagens celulares ST1 e P7, derivadas da linhagem celular C6, de glioma de rato. P7 é insensível ao tratamento com GC, enquanto ST1 apresenta reversão fenotípica tumoral→normal, gerando um bloqueio específico na fase G1. Um anti-soro policlonal específico para Brm e BRG1, foi gerado através da inoculaçâo de coelha com a proteína hBRG1 recombinante. Este antisoro foi utilizado para análisar os níveis destas proteínas nas duas linhagens celulares, sob ação de GC. Enquanto em ST1, Brm é induzida por GC, em células P7, o nível basal de Brm é relativamente alto, mantendo-se inalterado na presença de GC. A possíbilidade de existirem mutações no gene brm de células P7, foi investigada através de amplificação do DNA, por PCR, e seqüenciamento. A superexpressão de brm e BRG1 em células P7 mostrou que clones isolados apresentavam, de um modo geral, achatamento celular, diminuição da taxa de crescimento e da eficiência de plaqueamento em substrato sólido e semi-sólido. Alguns destes clones passaram a responder ao tratamento com GC, porém não tão drasticamente como as células ST1. Co-imunonoprecipitação mostrou algumas diferenças entre os complexos SWI/SNF de células ST1 e P7.
Glucocorticoid hormones (GCs) have been used as anti-inflammatory and anti-tumor agents, acting via nuclear receptors (GR) and being dependent on remodeling of the chromatin structure. As components of the global chromatin remodeling transcription complex (SWI/SNF), Brm and BRG-1 proteins play a key role in the action of GR. In order to study the mechanisms of action of GCs, we have been using the ST1 and P7 cell lines, derived from the C6, a rat glioma cell line. P7 is insensitive to the GC treatment, while ST1 displays a complete phenotypic reversion from tumoral to normal, including a G1-specific block in the cell cycle. A Brm and BRG1-specific polyclonal antiserum was generated, in rabbit, using recombinant hBRG1 protein as antigen. This antiserum was used to analyze the levels of Brm and BRG1 in these two cell lines, under GC treatment. While Brm is induced by GC, in ST1 cells, the basal level of Brm, in P7 cells, is relatively high, remaining unchanged under GC treatment. The possibility of brm mutations occurring in the P7 cells, was analyzed by DNA sequencing. Overexpression of brm and BRG1 in P7 cells led to morphological alterations (cell flattening) and decreased colony formation in agarose suspension and in solid substrate. Some of these clones became partially responsive to GC, when compared to the ST1 cell line. Co-immunoprecipitation assays revealed some differences in the SWI/SNF complex between ST1 and P7 cells.

Chronic myeloid leukaemia (CML) is characterised by a reciprocal chromosomal translocation that gives rise to a 22q-, or Philadelphia (Ph) chromosome and a derivative 9+. The translocation results in a chimaeric BCR-ABL gene which is expressed as a 210 kDa protein. The tyrosine kinase inhibitor imatinib mesylate (IM) specifically blocks the enzymatic activity of the BCR-ABL fusion protein and has been successfully employed for the treatment of CML. However, some patients develop resistance to IM and progress to blastic crisis (BC) which is usually fatal. Previous microarray screening of murine cell clones ectopically expressing graded amounts of BCR-ABL showed that ST14 mRNA levels correlated with those of BCR-ABL. ST14, encoding matriptase, acts as a tumour suppressor gene in solid tumours, but has also been linked to metastasis and invasion. The aim of my project is to understand the function of ST14 in CML. Taqman real time quantitative PCR showed that there was downregulation of ST14 expression in CD34 cells from CML chronic phase (CP) as compared to those from healthy individuals. These findings were further confirmed by experiments demonstrating upregulation of ST14 expression in Ph-pos cell lines upon IM treatment, a phenomenon not observed in Ph-neg lines. In order to study the effect of ST14 overexpression in CML cell lines, a retroviral vector encoding ST14 was used to infect Ph-pos cell lines (i.e. K562, KCL22 and LAMA84). Overexpression of ST14 in CML cell lines and primary cells significantly enhanced their migratory and invasion capacities. Intriguingly, it restored IM sensitivity in the KCL22 cell line which is intrinsically resistant to IM. The rescue of IM sensitivity in KCL22 overexpressing ST14 was independent of the level of BCR-ABL expression and unrelated to intracellular IM uptake, LYN and MET expression. The increased sensitivity to IM of KCL22 overexpressing ST14 was found to be associated with downregulation of BCL2 expression, a pro-survival protein. Furthermore, the analysis of ST14 expression in a group of IM treated CML CP patients from a clinical trial showed that a lower ST14 expression was associated with poorer molecular responses. The ST14 percentage at baseline was found to be a better predictor of achieving complete cytogenetic response (CCyR) at 12 months than the Sokal score. Overall, our findings were consistent with a tumour suppressor role for ST14. Future studies should focus on delineating the role of ST14 as a prognostic indicator in CML patients and its role in the mechanism of disease progression as well as IM resistance.
Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2014

CaaX proteins are involved in many key cellular processes such as proliferation, differentiation, trafficking, and gene expression. CaaX proteins have four specific C-terminal amino acids designated as a CaaX motif, where the “C” is a cysteine, “a” are aliphatic residues, and “X” represents one of several amino acids. Proteins with this motif undergo three post-translational modifications: isoprenylation of the cysteine residue, endoproteolysis of the –aaX residues and methylation of the isoprenylated cysteine, which is necessary for their localization in the cell and function. Due to involvement of CaaX proteins in many critical signaling pathways, mutations in CaaX proteins can result in a wide variety of disorders and carcinomas. Most notably, mutants in the KRAS gene are associated with 90% of pancreatic cancers and 30% of all cancers. Isoprenylcysteine carboxyl methyltransferase (Icmt), an integral membrane protein in the endoplasmic reticulum, is the only known protein responsible for the post-translational α-carboxyl methylesterification of the C-terminus of CaaX proteins. Cells with Icmt deficiency causes the small G-protein, K-ras, to be mislocalized and decreases downstream signaling of K-ras. Thus, our goal is to better understand the structure and methylation mechanism of Icmt in order to inhibit mutant K-ras in oncogenic cells and aid in the creation of a chemotherapeutic for pancreatic cancer.

Icmt studies have focused on the founding member of the Icmt family, Ste14. Ste14 is expressed in Saccharomyces cerevisiae (S. cerevisiae) and shares high homology with the human Icmt (hIcmt), which has yet to be functionally purified. Specifically, hIcmt and Ste14 share 63% similarity and 41% identity, mostly within the C-termini of the proteins. First, we optimized expression and purification of Ste14 in order to generate a larger yield of protein, which is necessary for many biophysical techniques. Infection of Sf9 cells with a baculovirus expressing an N-terminally 10-His-tagged and 3-myc-tagged Ste14 (His-Ste14), increased protein expression between four and five-fold compared to our yeast model and used significantly less starting materials. We also performed a detergent screen for the purification of His-Ste14 from insect cell expression. We concluded that n-Dodecyl-β-D-maltopyranoside (DDM), lauryl maltose neopentyl glycol (LMNG), and heptaethylene glycol monododecyl ether (C₁₂E₇) were detergents that stabilize His-Ste14 for further biophysical techniques. Additionally, we found 1xEQ buffer at pH 6.0 resulted in the most homogenous His-Ste14 sample.

Second, we sought to elucidate the SAM binding/ SAH release mechanism of His-Ste14 by utilizing a combinatorial method of site-directed spin labeling and electron paramagnetic resonance (EPR) spectroscopy analysis. We used SDSL-EPR to determine the conformational dynamics of His-Ste14 with and without SAM. EPR is an attractive method to study conformational changes of proteins as it is done in solution and requires relatively small amounts of protein. We generated a library of 46 non-conserved single cysteine mutants introduced into cysteine-less His-Ste14 (His-Ste14-TA). The cysteine residues engineered into His-Ste14-TA were in the cytosolic portion of the protein to ensure efficient labeling and were tested for methyltransferase activity levels. From crude membranes, only nineteen mutants retained activity levels of ≥50% of His-Ste14-TA, which were then purified and tested for methyltransferase activity levels. Eight purified mutants were selected as candidates for EPR with activity levels of ≥50% of His-Ste14-TA. Once optimized, we introduced a nitroxide spin label, 1-oxyl-2,2,5,5-tetrametylpyrroline-3-methyl)-methanethiosulfonate (MTSL), to several of the purified single cysteine mutants. Then, we evaluated protein dynamics during the methylation reaction by monitoring mobility of the MTSL-labelled residue upon addition of SAM. Overall, our structural and biochemical analyses will be used to ascertain the structural dynamics associated with SAM binding of this unique methyltransferase.

Additionally, we were able to incorporate His-Ste14 in nanodiscs. Nanodiscs mimic the membrane of a cell and are a more native-like environment that detergent micelles or liposomes. Since nanodiscs are conducive to many biophysical techniques, unlike detergents, we have begun preliminary studies to better understand the structure of Ste14. Techniques we have begun to pursue are negative stain electron microscopy (EM), single particle cryo-electron microscopy (cryo-EM), and X-ray crystallography.

Finally, we previously showed Ste14 functions as a dimer or higher order oligomer. Ste14 is comprised of six transmembrane (TM) domains in which TM1 contains a putative dimerization motif, G₃₁XXXG₃₅XXXG₃₉, where G is a glycine amino acid residue and X is a subset of hydrophobic amino acids. Using cysteine-scanning mutagenesis, we characterized TM1 cysteine mutants for their effects on protein expression, activity, and stability. We determined residues S27, Y28, L30, G31, G35, and G39 are critical for maintaining activity levels. Additionally, residues M25, T26, Y28, F41, P42, and Q43 were found to form strong dimers through the addition of sulfhydryl specific cross-linkers and immunoblot analysis. Recently, the purification of dimeric Ste14 from aggregated protein components via size exclusion chromatography (SEC) was improved for further experimentation. The purified, monodispersed, His-Ste14 underwent size exclusion chromatography (SEC), multi-angle light scattering (MALS) and small-angle X-ray scattering (SAXS) to confirm the dimerization state of Ste14. Together, we have used many biochemical and biophysical methods to gain insight about the structure, function, and mechanism of Ste14. Ultimately, our studies will be utilized to design more potent therapeutics to minimize K-Ras signaling in cancer cells.

The medial ganglionic eminence (MGE) is a progenitor domain in the subpallium that produces both locally-projecting interneurons which undergo tangential migration in structures such as the cortex as well as long-range projection neurons that occupy subcortical nuclei. Very little is known about the transcriptional mechanisms specifying the migratory behavior and axonal projection patterns of these two broad classes of MGE-derived neurons. In this study, I identify St18 as a novel transcriptional determinant specifying projection neuron fate in the MGE lineage. St18 is transiently expressed in the MGE subventricular zone (SVZ) and mantle, and I assessed its function using an ES cell-based model of MGE development. Induction of St18 is sufficient to direct ES-derived MGE neurons to adopt a projection neuron-like identity as defined by migration and morphology. Through gene expression analysis I identified a downstream effector of St18, Cbx7, which is a component of Polycomb repressor complex 1. I find that Cbx7 is essential for projection neuron-like migration and is not involved in St18-mediated projection neuron-like morphology. Using genetic loss-of-function in mice, I find that St18 is required for the production of globus pallidus pars externa (GPe) prototypic projection neurons. Single cell RNA sequencing revealed that St18 regulates MGE output of specific neuronal populations: in the absence of St18, I observe a large expansion of cortical interneurons at the expense of putative GPe neurons. I also find that, following St18 genetic loss of function, mouse walk cycles are disrupted downstream of a loss of a critical neuronal projection from the GPe to the sub thalamic nucleus (STN). These results characterize a novel transcriptional determinant that directs GPe prototypic projection neuron identity within the MGE lineage. Further, I have identified a downstream target of St18, Cbx7, which regulates only the migratory behavior of long-range projection neurons, suggesting that specific features of MGE projection neuron identity may be governed in a compartmentalized fashion by distinct transcriptional modules downstream of St18. I’ve also demonstrated the role of the GPe PV+ prototypic neurons in the production and maintenance of mouse locomotor gait.

碩士
臺北醫學大學
生醫材料暨組織工程研究所
103
Antrodia camphorata (A C) is a medicinal fungus that has previously demonstrated many beneficial properties such as cytotoxicity to cancer cells and amelioration of inflammation syndromes. This study evaluates pure compound extracts of A C for osteogenesis, osteoporosis recovery, and osteoporotic bone injury healing effects in vitro with preosteoblast cells (MC3T3) and in vivo with an osteoporosis mouse model established in our previous studies, ovariectomied senescence accelerated mice (OVX-SAMP8). This study demonstrated that ST1 is a well-defined pure compound of A C that exhibits low cytotoxicity to preosteoblasts at 25 ug/mL, while osteogenic gene expression (RUNX2, OPN and OCN) is significantly up-regulated, and revealed an increased ratio of OPG to RANKL, indicating maintenance of the bone matrix through inhibition of osteoclastic pathway. Additionally, evaluation by Alizarin Red S staining showed increased mineralization in ST1 treated preosteoblasts. In vitro results show that ST1 could promote osteogenesis and inhibit bone digestion. In vivo testing examined both long term and short term effects of ST1 on OVX-SAMP8 mice. Short term treatment was evaluated on an osteoporotic bone injury model. Our results showed that ST1 administered by i.p. injection every other day for 2 weeks following a bone injury improved the rate of bone healing when compared to Sham group. In our long term study, OVX-SAMP8 mice were treated orally with ST1 every other day for 4 months. Osteogenesis was improved in BMSCs from the ST1 treated mice, however, possible side effects were observed. ST1 could be considered for short term osteoporosis or osteoporotic fracture therapy through anabolic action on bone health.

Gene expression of porin and beta-lactamases genes during the beta-lactam antibiotic treatment and effect of inoculum size on Klebsiella pneumoniae clinical isolates ABSTRACT In recent years, Klebsiella pneumoniae has been increasingly reported to be one of the most important nosocomial pathogens, and it is usually resistant to many antibiotics. In this work, we focused on the expression of the AmpC group β- lactamase DHA-1 and its negative regulator AmpR, as well as the porins OmpK35 and OmpK36 and on effect of inoculum. We used well-characterized Klebsiella pneumoniae strains in this study. Plasmids obtained from these strains were also transformed into different wild-type Klebsiella pneumoniae strains, which were typed by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Gene expression analysis was performed by RT-PCR using specific primers and TaqMan probes. In most strains, expression was dependent on the presence of an inducer. The highly resistant strain showed a different expression pattern, but the expression of blaDHA-1 remained inducible by cefoxitin. Different regulation was also observed in the transformants. Based on our data, we suggest that the previously described regulatory pathway for AmpC is not generally suitable, and we propose that there are more...

博士
國立成功大學
基礎醫學研究所
104
STK4 is a serine/threonine kinase protein encoded for 487 amino acids which plays an important role in Hippo pathway involved in development progression. Disease associated with STK4 down-regulation induces tumor recurrent and hepatocellular carcinoma formation. However, the regulation mechanism of protein expression and function are still not clear. To address the STK4 protein function in the creatures that model organism C.elegans were used to answer this question. The intestinal tract distance of cst-1 knock-out has wider than control group and premature aging has been shown. -catenin homologous bar-1 is also involved in intestinal tract development regulation mechanism. The premature aging and intestine abnormality can be restored under bar-1 down-regulated with cst-1 over-expressed. STK4 protein expression level regulation mechanism is still unknown. One possibility is post-transcriptional regulation through miRNA targeting mRNA 3’UTR degradation. The function assay and clinical samples showed that miR-18a indeed is an oncomiR to suppress STK4 induced apoptosis cascade through AKT phosphorylation regulation. Above the data from C. elegans,beta-catenin can be the candidate target interacted with STK4 in the same axis to regulate digestive tract development. IHC staining of different kinds of tumor parts showed that STK4 are highly expressed in prostate, liver and colon compared with normal specimens. All of our study indicated that STK4 is a tumor suppressor interacted with beta-catenin in prostate and colon cancers. The protein synthesis is through miRNA mediated degradation. The study demonstrated that STK4 can be the therapeutic target for prostate and colon cancer.

Huntington’s disease (HD) is a neurodegenerative disorder caused by the inheritance of one mutant copy of the huntingtin gene. Mutant huntingtin protein (mHtt) contains an expanded polyglutamine repeat region near the N-terminus. Cleavage of mHtt releases an N-terminal fragment (N-mHtt) which translocates, and accumulates in the nucleus. Nuclear accumulation of N-mHtt has been directly associated with cellular toxicity. Decreased transcription is among the earliest detected changes that occur in the brains of HD patients and is consistently observed in all animal and cellular models of HD. Transcriptional dysregulation may trigger many of the perturbations that occur later in disease progression and an understanding of the effects of mHtt may lead to strategies to slow the progression of the disease. Current models of N-mHtt-mediated transcriptional dysregulation suggest that abnormal interactions between N-mHtt and transcription factors impair the ability of these transcription factors to associate at N-mHtt-affected promoters and properly regulate gene expression. We tested various aspects of these models using two N-mHtt-affected promoters in in vitro transcription assays and in two cell models of HD using techniques including overexpression of known N-mHtt-interacting transcription factors, chromatin immunoprecipitation, promoter deletion and mutation analyses and in vitro promoter binding assays. Based on our results and those in the literature, we proposed a new model of N-mHtt-mediated transcriptional dysregulation centered on the presence of N-mHtt at affected promoters. We concluded that simultaneous interaction of N-mHtt with multiple binding partners within the transcriptional machinery would explain the gene-specificity of N-mHtt-mediated transcriptional dysregulation, as well as the observation that some genes are affected early in disease progression while others are affected later. Our model explains why alleviating N-mHtt-mediated transcriptional dysregulation through overexpression of N-mHtt-interacting proteins has proven to be difficult and suggests that the most realistic strategy for restoring gene expression across the spectrum of N-mHtt affected genes is by reducing the amount of soluble nuclear N-mHtt.