Polycomb at the Crossroads: An Integrated Model with LncRNA- and Silencer-mediated Repression

Correct gene expression is achieved by controlling the balance of transcriptional activation and repression, the latter including direct silencer-, Polycomb- and, more recently identified IncRNA-mediated repression. Here, we describe the known and possible cross-talk mechanisms within and beween these modes of repression. We discuss these mechanisms within the framework of recruitment to as well as organization of the chromatin and propose possible research orientations that would aim to further resolve the links within certain of these modes of repression, notably between Polycomb-, IncRNA- and silencer-mediated silencing.