The role of long non-coding RNA in transcriptional gene silencing

Transcriptional gene silencing controls the activity of transposable elements and expression of protein-coding genes. It requires non-coding transcription, which in plants is performed by RNA Polymerases IV and V (Pol IV and Pol V). Pol IV produces precursors for siRNA biogenesis while Pol V produces scaffold transcripts required for siRNAs and associated proteins to recognize their target loci. In this review I discuss the mechanisms used by Pol IV and Pol V to mediate repressive chromatin modifications. I further discuss the mechanisms controlling non-coding transcription and their role in regulation of genome activity.