Project

The three HP1 proteins (Heterochromatin Protein 1 alpha, -beta, -gamma) are epigenetic markers of heterochromatin, the condensed, repressed form of chromatin. They are typically known to associate to the di-/tri-methylated lysine 9 of histone H3 (H3-K9me2/3), a repressive histone mark, HP1s are therefore linked to chromatin silencing. But on the other hand, HP1s are also linked to activated transcription, for example HP1g has been shown to localize within the body of coding genes in correlation with their transcriptional activity. We focus on the mechanisms linking HP1gamma to regulation of chromatin and transcription in response to cellular stimuli. We are dissecting the functional links between HP1 proteins and chromatin-associated RNA. For this purpose, have identified all RNA populations associated with HP1gamma factor in immortalized cell lines derived from MEF (mouse embryonic fibroblast) with or without stimuli. We are now analysing the functional impact on gene expression levels. This should allow us to understand to what extend HP1gamma is associated to transcriptional processes on the chromatin.