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H3K9 Acetylation (h3k9 + acetylation)
Selected AbstractsEpigenetic control of translation regulation: Alterations in histone H3 lysine 9 post-translation modifications are correlated with the expression of the translation initiation factor 2B (Eif2b5) during thermal control establishmentDEVELOPMENTAL NEUROBIOLOGY, Issue 2 2010Tatiana Kisliouk Abstract Thermal control set point is regulated by thermosensitive neurons of the preoptic anterior hypothalamus (PO/AH) and completes its development during postnatal critical sensory period. External stimuli, like increase in environmental temperature, influence the neuronal protein repertoire and, ultimately, cell properties via activation or silencing of gene transcription, both of which are regulated by the "histone code."" Here, we demonstrated an increase in global histone H3 lysine 9 (H3K9) acetylation as well as H3K9 dimethylation in chick PO/AH during heat conditioning at the critical period of sensory development. In contrast to the global profile of H3K9 modifications, acetylation and dimethylation patterns of H3K9 at the promoter of the catalytic subunit of eukaryotic translation initiation factor 2B (Eif2b5) were opposite to each other. During heat conditioning, there was an increase in H3K9 acetylation at the Eif2b5 promoter, simultaneously with decrease in H3K9 dimethylation. These alterations coincided with Eif2b5 mRNA induction. Moreover, exposure to excessive heat during the critical period resulted in long-term effect on both H3K9 tagging at the Eif2b5 promoter and Eif2b5 mRNA expression. These data suggest a role for dynamic H3K9 post-translational modifications in global translation regulation during the thermal control establishment. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2010 [source] Thioredoxin interacting protein (TXNIP) induces inflammation through chromatin modification in retinal capillary endothelial cells under diabetic conditionsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2009Lorena Perrone Chronic hyperglycemia and activation of receptor for advanced glycation end products (RAGE) are known risk factors for microvascular disease development in diabetic retinopathy. Thioredoxin-interacting protein (TXNIP), an endogenous inhibitor of antioxidant thioredoxin (TRX), plays a causative role in diabetes and its vascular complications. Herein we investigate whether HG and RAGE induce inflammation in rat retinal endothelial cells (EC) under diabetic conditions in culture through TXNIP activation and whether epigenetic mechanisms play a role in inflammatory gene expression. We show that RAGE activation by its ligand S100B or HG treatment of retinal EC induces the expression of TXNIP and inflammatory genes such as Cox2, VEGF-A, and ICAM1. TXNIP silencing by siRNA impedes RAGE and HG effects while stable over-expression of a cDNA for human TXNIP in EC elevates inflammation. p38 MAPK-NF-,B signaling pathway and histone H3 lysine (K) nine modifications are involved in TXNIP-induced inflammation. Chromatin immunoprecipitation (ChIP) assays reveal that TXNIP over-expression in EC abolishes H3K9 tri-methylation, a marker for gene inactivation, and increases H3K9 acetylation, an indicator of gene induction, at proximal Cox2 promoter bearing the NF-,B-binding site. These findings have important implications toward understanding the molecular mechanisms of ocular inflammation and endothelial dysfunction in diabetic retinopathy. J. Cell. Physiol. 221: 262,272, 2009. © 2009 Wiley-Liss, Inc [source] 5, flanking region of var genes nucleate histone modification patterns linked to phenotypic inheritance of virulence traits in malaria parasitesMOLECULAR MICROBIOLOGY, Issue 6 2007Jose Juan Lopez-Rubio Summary In the human malaria parasite Plasmodium falciparum antigenic variation facilitates long-term chronic infection of the host. This is achieved by sequential expression of a single member of the 60-member var family. Here we show that the 5, flanking region nucleates epigenetic events strongly linked to the maintenance of mono-allelic var gene expression pattern during parasite proliferation. Tri- and dimethylation of histone H3 lysine 4 peak in the 5, upstream region of transcribed var and during the poised state (non-transcribed phase of var genes during the 48 h asexual life cycle), ,bookmarking' this member for re-activation at the onset of the next cycle. Histone H3 lysine 9 trimethylation acts as an antagonist to lysine 4 methylation to establish stably silent var gene states along the 5, flanking and coding region. Furthermore, we show that competition exists between H3K9 methylation and H3K9 acetylation in the 5, flanking region and that these marks contribute epigenetically to repressing or activating var gene expression. Our work points to a pivotal role of the histone methyl mark writing and reading machinery in the phenotypic inheritance of virulence traits in the malaria parasite. [source] In vitro specificities of Arabidopsis co-activator histone acetyltransferases: implications for histone hyperacetylation in gene activationTHE PLANT JOURNAL, Issue 4 2007Keith W. Earley Summary In genetic hybrids displaying nucleolar dominance, acetylation of lysines 5, 8, 12 and 16 of histone H4 (H4K5, H4K8, H4K12, H4K16) and acetylation of histone H3 on lysines 9 and 14 (H3K9, H3K14) occurs at the promoters of active ribosomal RNA (rRNA) genes, whereas silenced rRNA genes are deacetylated. Likewise, histone hyperacetylation correlates with the active state of transgenes and of endogenous plant genes involved in physiological processes, including cold tolerance, light-responsiveness and flowering. To investigate histone hyperacetylation dynamics we used sodium butyrate, a histone deacetylase inhibitor known to switch silent rRNA genes on, in order to enrich the pool of acetylated histones. Mass spectrometric analyses revealed unique mono- (K16Ac), di- (K12Ac, K16Ac), tri- (K8Ac, K12Ac, K16Ac), and tetra-acetylated (K5Ac, K8Ac, K12Ac, K16Ac) histone H4 isoforms, suggesting that H4 hyperacetylation occurs in a processive fashion, beginning with lysine 16 and ending with lysine 5. Using a combination of molecular and mass spectrometric assays we then determined the specificities of seven of the nine functional co-activator type histone acetyltransferases (HATs) in Arabidopsis thaliana: specifically HATs of the CBP (HAC1, HAC5, HAC12), GNAT (HAG1, HAG2), and MYST families (HAM1, HAM2). Specific HATs acetylate histone H4K5 (HAM1, HAM2), H4K12 (HAG2), and H3K14 (HAG1), suggesting that acetylation of these lysines may have special regulatory significance. Other acetylation events, including histone H3K9 acetylation, are likely to result from the activities of the broad-specificity HAC1, HAC5, and HAC12 histone acetyltransferases. [source] | ||||||||||