Transcriptional read-through is not sufficient to induce an epigenetic switch in the silencing activity of Polycomb response elements

• DOI: 10.1073/pnas.1515276112
• Publication Date: 2015-10-27T02:38:47Z
• Authors: Maksim Erokhin; Pavel Elizar’ev; Aleksander Parshikov; Paul Schedl; Pavel Georgiev; Darya Chetverina
• Keywords: Transcription; Polycomb-group proteins

In Drosophila, Polycomb (PcG) and Trithorax (TrxG) group proteins are assembled on response elements (PREs) to maintain tissue stage-specific patterns of gene expression. Critical coordinating expression with the process differentiation, activity PREs can be switched "on" "off." When on, PRE imposes a silenced state genes in same domain that is stably inherited through multiple rounds cell division. off, permissive for inherited. Previous studies have suggested burst transcription sequence displaces PcG provides universal mechanism inducing heritable switch from off; however, evidence favoring this model indirect. Here, we directly tested transcriptional read-through mechanism. Contrary previous suggestions, show not sufficient an epigenetic activity. fact, even high levels continuous fails dislodge proteins, nor does it remove repressive histone marks. Our results indicate other mechanisms involving adjacent DNA regulatory must implicated