RRC ID 51336
Author Kalinava N, Ni JZ, Peterman K, Chen E, Gu SG.
Title Decoupling the downstream effects of germline nuclear RNAi reveals that H3K9me3 is dispensable for heritable RNAi and the maintenance of endogenous siRNA-mediated transcriptional silencing in Caenorhabditis elegans.
Journal Epigenetics Chromatin
Abstract BACKGROUND:Germline nuclear RNAi in C. elegans is a transgenerational gene-silencing pathway that leads to H3K9 trimethylation (H3K9me3) and transcriptional silencing at the target genes. H3K9me3 induced by either exogenous double-stranded RNA (dsRNA) or endogenous siRNA (endo-siRNA) is highly specific to the target loci and transgenerationally heritable. Despite these features, the role of H3K9me3 in siRNA-mediated transcriptional silencing and inheritance of the silencing state at native target genes is unclear. In this study, we took combined genetic and whole-genome approaches to address this question.
RESULTS:Here we demonstrate that siRNA-mediated H3K9me3 requires combined activities of three H3K9 histone methyltransferases: MET-2, SET-25, and SET-32. set-32 single, met-2 set-25 double, and met-2 set-25;set-32 triple mutant adult animals all exhibit prominent reductions in H3K9me3 throughout the genome, with met-2 set-25;set-32 mutant worms losing all detectable H3K9me3 signals. Surprisingly, loss of high-magnitude H3K9me3 at the native nuclear RNAi targets has no effect on the transcriptional silencing state. In addition, the exogenous dsRNA-induced transcriptional silencing and heritable RNAi at oma-1, a well-established nuclear RNAi reporter gene, are completely resistant to the loss of H3K9me3.
CONCLUSIONS:Nuclear RNAi-mediated H3K9me3 in C. elegans requires multiple histone methyltransferases, including MET-2, SET-25, and SET-32. H3K9me3 is not essential for dsRNA-induced heritable RNAi or the maintenance of endo-siRNA-mediated transcriptional silencing in C. elegans. We propose that siRNA-mediated transcriptional silencing in C. elegans can be maintained by an H3K9me3-independent mechanism.
Volume 10
Pages 6
Published 2017-2-15
DOI 10.1186/s13072-017-0114-8
PII 114
PMID 28228846
PMC PMC5311726
MeSH Animals Caenorhabditis elegans / genetics* Caenorhabditis elegans / metabolism Caenorhabditis elegans Proteins / antagonists & inhibitors Caenorhabditis elegans Proteins / genetics Caenorhabditis elegans Proteins / metabolism* Carrier Proteins / antagonists & inhibitors Carrier Proteins / genetics Carrier Proteins / metabolism Chromatin Immunoprecipitation Genome Genomic Instability Germ Cells / metabolism High-Throughput Nucleotide Sequencing Histone Methyltransferases Histone-Lysine N-Methyltransferase / genetics Histone-Lysine N-Methyltransferase / metabolism Histones / genetics Histones / metabolism* Methylation Microscopy, Fluorescence Mutagenesis RNA Interference* RNA, Double-Stranded / metabolism RNA, Messenger / metabolism RNA, Small Interfering / metabolism* Real-Time Polymerase Chain Reaction Sequence Analysis, RNA Transcription, Genetic
IF 4.237
Times Cited 26
C.elegans tm1200 tm3526