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Initiation and maintenance of transcriptional states are critical for controlling normal tissue homeostasis and differentiation. The cyclin dependent kinases CDK8 and CDK19 (Mediator kinases) are regulatory components of Mediator, a highly conserved complex that orchestrates enhancer-mediated transcriptional output. While Mediator kinases have been implicated in the transcription of genes necessary for development and growth, its function in mammals has not been well defined. Using genetically defined models and pharmacological inhibitors, we showed that CDK8 and CDK19 function in a redundant manner to regulate intestinal lineage specification in humans and mice. The Mediator kinase module bound and phosphorylated key components of the chromatin remodeling complex switch/sucrose non-fermentable (SWI/SNF) in intestinal epithelial cells. Concomitantly, SWI/SNF and MED12-Mediator colocalized at distinct lineage-specifying enhancers in a CDK8/19-dependent manner. Thus, these studies reveal a transcriptional mechanism of intestinal cell specification, coordinated by the interaction between the chromatin remodeling complex SWI/SNF and Mediator kinase., Introduction The intestinal epithelium is among the most proliferative tissues, with a complete turnover of intestinal epithelial cells (IECs) every 3 to 5 days. The self-renewal capacity of the intestinal [...]

This study is aimed at isolating and identifying a thermophilic cellulolytic bacterium from hot spring water and characterizing thermostable cellulase produced by the isolate. Enrichment and culture of water sample was used for isolation of bacterial strains and an isolate with highest cellulase activity was chosen for the production, partial purification, and biochemical characterization of the enzyme. Different staining techniques, enzymatic tests, and 16s ribosomal DNA (16s rDNA) gene sequencing were used for the identification of the isolate. The cellulase producing isolate was Gram positive, motile, and sporulated rod-shaped bacterium growing optimally between 55°C and 65°C. Based on partial 16s rDNA sequence analysis, the isolate was identified as Geobacillus sp. and was designated as Geobacillus sp. KP43. The cellulase enzyme production condition was optimized, and the product was partially purified and biochemically characterized. Optimum cellulase production was observed in 1% carboxymethyl cellulose (CMC) at 55°C. The molecular weight of the enzyme was found to be approximately 66 kDa on 12% SDS-PAGE analysis. Biochemical characterization of partially purified enzyme revealed the temperature optimum of 70°C and activity over a wide pH range. Further, cellulase activity was markedly stimulated by metal ion Fe2+. Apart from cellulases, the isolate also depicted good xylanase, cellobiase, and amylase activities. Thermophilic growth with a variety of extracellular enzyme activities at elevated temperature as well as in a wide pH range showed that the isolated bacteria, Geobacillus sp. KP43, can withstand the harsh environmental condition, which makes this organism suitable for enzyme production for various biotechnological and industrial applications. [ABSTRACT FROM AUTHOR]

R3798 --> Uterine fibroids are benign tumors that occur in the myometrium of the uterus. Although they are benign, they represent a significant health problem as they affect approximately 70% of women and cause pregnancy complications, infertility and menstrual disorders. These health issues are especially concerning as uterine fibroids affect women of reproductive age. To date, non‐invasive, long‐term treatment options for uterine fibroids are not available. Thus, a significant need remains to develop non‐invasive long‐term treatment options for uterine fibroids. Strikingly, 70% of uterine fibroids have mutations in a protein called MED12. MED12 is one of 3 proteins that constitute the Mediator kinase complex. Together, these proteins (MED12, MED13, CYCLIN C and CDK8/19) function as a complex to integrate and transduce signals to RNA polymerase II, and thereby regulate transcription in response to numerous signaling pathways. Interestingly, our lab has previously demonstrated that these MED12 mutations lead to a loss of Mediator kinase activity. Thus, we hypothesize that this loss of Mediator kinase activity promotes uterine fibroid formation by dysregulating cellular processes. The goal of this work was to identify substrates that are phosphorylated by Mediator kinase in uterine fibroid progenitor cells, myometrium side population (MyoSP) cells, in order to understand how loss of Mediator kinase activity might promote the development of uterine fibroids. In order to identify proteins that are phosphorylated by Mediator kinase, MyoSP cells were metabolically labeled with either heavy or light stable isotopes and treated with vehicle or a specific inhibitor of Mediator kinase. Mass spectrometry was used to identify and quantify phosphoproteins from each condition (inhibitor treated vs. vehicle treated). An Empirical Bayes analysis was used to identify 307 phosphoproteins that significantly decreased upon treatment with the Mediator kinase inhibitor. Of these proteins, 4 (STAT1, TP53BP1, FOXK1, and NELFB) were further validated as direct targets of Mediator kinase by in‐vitro kinase assay. In conclusion, this work identifies direct substrates of Mediator kinase that can be investigated for their roles in promoting uterine fibroid formation and represent potential targets for novel therapies to treat uterine fibroids. [ABSTRACT FROM AUTHOR]