Project description:RNA helicases perform essential housekeeping and regulatory functions in all domains of life by binding and unwinding RNA molecules. The Ski2-like proteins are primordial helicases that play an active role in eukaryotic RNA homeostasis pathways, with multiple homologs having specialized functions. The significance of the expansion and diversity of Ski2-like proteins in Archaea, the third domain of life, has not yet been established. Here, by studying the phylogenetic diversity of Ski2-like helicases among archaeal genomes and the enzymatic activities of those in Thermococcales, we provide further evidence of the function of this protein family in archaeal metabolism of nucleic acids. We show that, in the course of evolution, ASH-Ski2 and Hel308-Ski2, the two main groups of Ski2-like proteins, have diverged in their biological functions. Whereas Hel308 has been shown to mainly act on DNA, we show that ASH-Ski2, previously described to be associated with the 5′-3′ aRNaseJ exonuclease, acts on RNA by supporting an efficient annealing activity, but also an RNA unwinding with a 3′-5′ polarity. To gain insights into the function of Ski2, we also analyse the transcriptome of Thermococcus barophilus ASH-Ski2 mutant strain and provide evidence of the importance of ASH-Ski2 in cellular metabolism pathways related to translation.
Project description:Alcoholic hepatitis (AH) continues to be a disease with high mortality and no efficacious medical treatment. Although severe AH is presented as acute on chronic liver failure, what underlies this transition from chronic alcoholic steatohepatitis (ASH) to AH, is largely unknown. To address this question, unbiased RNA-seq and proteomic analyses were performed on livers of the recently developed AH mouse model which exhibits the shift to AH from chronic ASH upon weekly alcohol binge, and these results are compared with gene expression profiling data from AH patients. This cross-analysis has identified Casp11 (CASP4 in man) as a commonly upregulated gene known to be involved in non-canonical inflammasome pathway. Immunoblotting confirms CASP11/4 activation in AH mice but not in chronic ASH. Gasdermin-D (GSDMD) which induces pyroptosis (lytic cell death caused by bacterial infection) downstream of CASP11/4 activation, is also activated in AH livers. CASP11 deficiency reduces GSDMD activation, bacterial load in the liver, and the severity of AH. Conversely, the deficiency of IL-18, the key anti-microbial cytokine, aggravates hepatic bacterial load, GSDMD activation, and AH. Further, hepatocyte-specific expression of constitutively active GSDMD worsens hepatocellular lytic death and PMN inflammation. These results implicate pyroptosis induced by CASP11/4-GSDMD pathway in the pathogenesis of AH.
Project description:modENCODE_submission_6291 This submission comes from a modENCODE project of Jason Lieb. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: The focus of our analysis will be elements that specify nucleosome positioning and occupancy, control domains of gene expression, induce repression of the X chromosome, guide mitotic segregation and genome duplication, govern homolog pairing and recombination during meiosis, and organize chromosome positioning within the nucleus. Our 126 strategically selected targets include key histone modifications and histone variants. We will integrate information generated with existing knowledge on the biology of the targets and perform ChIP-seq analysis on mutant and RNAi extracts lacking selected target proteins. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf EXPERIMENT TYPE: CHIP-seq. BIOLOGICAL SOURCE: Strain: N2; Developmental Stage: Mixed Embryo; Genotype: wild type; Sex: mixed Male and Hermaphrodite population; EXPERIMENTAL FACTORS: Developmental Stage Mixed Embryo; temp (temperature) 20 degree celsius; Strain N2; Antibody ASH-2 SDQ4585 (target is ASH-2)
Project description:ASH-1 orthologs are H3K36-specific methyltransferases that are conserved from fungi to humans but are poorly understood, in part because they are typically essential for viability. Here we examine the H3K36 methylation pathway of Neurospora crassa, which we find has just two H3K36 methyltransferases, ASH-1 and RNA polymerase II-associated SET-2. Our investigation of the interplay between SET-2 and ASH-1 uncovered a regulatory mechanism connecting ASH-1-catalyzed H3K36 methylation to repression of poorly transcribed genes. Our findings provide new insight into ASH-1 function, H3K27me2/3 establishment, and repression at facultative heterochromatin.
Project description:modENCODE_submission_5231 This submission comes from a modENCODE project of Jason Lieb. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: The focus of our analysis will be elements that specify nucleosome positioning and occupancy, control domains of gene expression, induce repression of the X chromosome, guide mitotic segregation and genome duplication, govern homolog pairing and recombination during meiosis, and organize chromosome positioning within the nucleus. Our 126 strategically selected targets include RNA polymerase II isoforms, dosage-compensation proteins, centromere components, homolog-pairing facilitators, recombination markers, and nuclear-envelope constituents. We will integrate information generated with existing knowledge on the biology of the targets and perform ChIP-seq analysis on mutant and RNAi extracts lacking selected target proteins. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf EXPERIMENT TYPE: CHIP-seq. BIOLOGICAL SOURCE: Strain: fem-2(b245); Developmental Stage: Germline containing young adult; Genotype: fem-2(b245)III; Sex: Hermaphrodite; EXPERIMENTAL FACTORS: Developmental Stage Germline containing young adult; temp (temperature) 20 degree Celsius; Strain fem-2(b245); Antibody ASH-2 SDQ3989 (target is ASH-2)