title: Endogenous RNA interference is driven by copy number.
abstract: A plethora of non-protein coding RNAs are produced throughout eukaryotic genomes, many of which are transcribed antisense to protein-coding genes and could potentially instigate RNA interference (RNAi) responses. Here we have used a synthetic RNAi system to show that gene copy number is a key factor controlling RNAi for transcripts from endogenous loci, since transcripts from multi-copy loci form double stranded RNA more efficiently than transcripts from equivalently expressed single-copy loci. Selectivity towards transcripts from high-copy DNA is therefore an emergent property of a minimal RNAi system. The ability of RNAi to selectively degrade transcripts from high-copy loci would allow suppression of newly emerging transposable elements, but such a surveillance system requires transcription. We show that low-level genome-wide pervasive transcription is sufficient to instigate RNAi, and propose that pervasive transcription is part of a defense mechanism capable of directing a sequence-independent RNAi response against transposable elements amplifying within the genome. DOI: http://dx.doi.org/10.7554/eLife.01581.001.
authors: Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom.
authors: Cristina
authors: C
authors: Cruz
authors: Jonathan
authors: J
authors: Houseley
mesh_terms: D060565:Argonaute Proteins / Q000235:genetics / Q000378:metabolism; D018628:Gene Dosage; D015966:Gene Expression Regulation, Fungal; D016681:Genome, Fungal; D034622:RNA Interference; D012331:RNA, Fungal / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics* / Q000378:metabolism; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D060565:Argonaute Proteins; D012331:RNA, Fungal; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D029701:Saccharomyces cerevisiae Proteins; D043244:Ribonuclease III
keywords: RNA interference; copy number; non-coding RNA; pervasive transcription