Mycobacterium tuberculosis EsxL inhibits MHC-II expression by promoting hypermethylation in class-II transactivator loci in macrophagesMycobacterium tuberculosis is known to modulate the host immune responses to facilitate its persistence inside the host cells. One of the key mechanisms includes repression of class-II transactivator (CIITA) and MHC-II expression in infected macrophages. However, the precise mechanism of CIITA and MHC-II down-regulation is not well studied. M. tuberculosis 6-kDa early secretory antigenic target (ESAT-6) is a known potent virulence and antigenic determinant. The M. tuberculosis genome encodes 23 such ESAT-6 family proteins.
Dimethylated H3K27 Is a Repressive Epigenetic Histone Mark in the Protist Entamoeba histolytica and Is Significantly Enriched in Genes Silenced via the RNAi PathwayBackground: Entamoeba histolytica has an RNAi-mediated TGS pathway but the epigenetic marks are not known.Results: H3K27Me2 is an inducible repressive histone modification enriched in loci silenced by small RNAs.Conclusion: Transcriptional gene silencing and chromatin modification are coupled to maintain prolonged gene silencing.Significance: This work identifies the first repressive histone mark in Entamoeba and links it to RNAi.