RRC ID 45592
Author Leopold LE, Heestand BN, Seong S, Shtessel L, Ahmed S.
Title Lack of pairing during meiosis triggers multigenerational transgene silencing in Caenorhabditis elegans.
Journal Proc. Natl. Acad. Sci. U.S.A.
Abstract Single-copy transgenes in Caenorhabditis elegans can be subjected to a potent, irreversible silencing process termed small RNA-induced epigenetic silencing (RNAe). RNAe is promoted by the Piwi Argonaute protein PRG-1 and associated Piwi-interacting RNAs (piRNAs), as well as by proteins that promote and respond to secondary small interfering RNA (siRNA) production. Here we define a related siRNA-mediated silencing process, termed "multigenerational RNAe," which can occur for transgenes that are maintained in a hemizygous state for several generations. We found that transgenes that contain either GFP or mCherry epitope tags can be silenced via multigenerational RNAe, whereas a transgene that possesses GFP and a perfect piRNA target site can be rapidly and permanently silenced via RNAe. Although previous studies have shown that PRG-1 is typically dispensable for maintenance of RNAe, we found that both initiation and maintenance of multigenerational RNAe requires PRG-1 and the secondary siRNA biogenesis protein RDE-2. Although silencing via RNAe is irreversible, we found that transgene expression can be restored when hemizygous transgenes that were silenced via multigenerational RNAe become homozygous. Furthermore, multigenerational RNAe was accelerated when meiotic pairing of the chromosome possessing the transgene was abolished. We propose that persistent lack of pairing during meiosis elicits a reversible multigenerational silencing response, which can lead to permanent transgene silencing. Multigenerational RNAe may be broadly relevant to single-copy transgenes used in experimental biology and to shaping the epigenomic landscape of diverse species, where genomic polymorphisms between homologous chromosomes commonly result in unpaired DNA during meiosis.
Volume 112(20)
Pages E2667-76
Published 2015-5-19
DOI 10.1073/pnas.1501979112
PII 1501979112
PMID 25941370
PMC PMC4443339
MeSH ATP-Binding Cassette Transporters / genetics ATP-Binding Cassette Transporters / metabolism Animals Argonaute Proteins / genetics Argonaute Proteins / metabolism Caenorhabditis elegans / genetics* Caenorhabditis elegans / physiology Caenorhabditis elegans Proteins / genetics Caenorhabditis elegans Proteins / metabolism DNA Primers / genetics Gene Silencing / physiology* Green Fluorescent Proteins / genetics Luminescent Proteins / genetics Meiosis / physiology* Microscopy, Fluorescence Microscopy, Interference RNA, Small Interfering / genetics Transgenes / genetics*
IF 9.504
Times Cited 3
C.elegans tm872 tm574 tm1813