The Dictyostelium discoideum RNA-dependent RNA polymerase RrpC silences the centromeric retrotransposon DIRS-1 post-transcriptionally and is required for the spreading of RNA silencing signals
Dictyostelium intermediate repeat sequence 1 (DIRS-1) is the founding member of a poorly characterized class of retrotransposable elements that contain inverse long terminal repeats and tyrosine recombinase instead of DDE-type integrase enzymes. In Dictyostelium discoideum, DIRS-1 forms clusters that adopt the function of centromeres, rendering tight retrotransposition control critical to maintaining chromosome integrity. We report that in deletion strains of the RNA-dependent RNA polymerase RrpC, full-length and shorter DIRS-1 messenger RNAs are strongly enriched. Shorter versions of a hitherto unknown long non-coding RNA in DIRS-1 antisense orientation are also enriched in rrpC- strains. Concurrent with the accumulation of long transcripts, the vast majority of small (21 mer) DIRS-1 RNAs vanish in rrpC- strains. RNASeq reveals an asymmetric distribution of the DIRS-1 small RNAs, both along DIRS-1 and with respect to sense and antisense orientation. We show that RrpC is required for post-transcriptional DIRS-1 silencing and also for spreading of RNA silencing signals. Finally, DIRS-1 mis-regulation in the absence of RrpC leads to retrotransposon mobilization. In summary, our data reveal RrpC as a key player in the silencing of centromeric retrotransposon DIRS-1. RrpC acts at the post-transcriptional level and is involved in spreading of RNA silencing signals, both in the 5' and 3' directions.
|ISBN||1362-4962 (Electronic) 0305-1048 (Linking)|
|Authors||Wiegand, S. ; Meier, D. ; Seehafer, C. ; Malicki, M. ; Hofmann, P. ; Schmith, A. ; Winckler, T. ; Foldesi, B. ; Boesler, B. ; Nellen, W. ; Reimegard, J. ; Kaller, M. ; Hallman, J. ; Emanuelsson, O. ; Avesson, L. ; Soderbom, F. ; Hammann, C.;|
|Publisher Name||NUCLEIC ACIDS RESEARCH|
|URL link to publisher's version||http://www.ncbi.nlm.nih.gov/pubmed/24369430|
|OpenAccess link to author's accepted manuscript version||https://publications.gimr.garvan.org.au/open-access/12484|