Project description:The Set1 family of histone H3 lysine 4 (H3K4) methyltransferases is highly conserved from yeast to humans. Here we show that the Set1 complex (Set1C) directly binds RNA in vitro through the regions that comprise the double RNA recognition motifs (dRRM) and N-SET domain within Set1 and its subunit Spp1. To investigate the functional relevance of RNA binding, we performed UV RNA cross-linking (CRAC) for Set1 and RNA polymerase II in parallel with ChIP-seq experiments. Set1 binds nascent transcripts through its dRRM. RNA binding is important to define the appropriate topology of Set1C distribution along transcription units and correlates with the efficient deposition of the H3K4me3 mark. In addition, we uncovered that Set1 binds to different classes of RNAs to levels that largely exceed the levels of binding to the general population of transcripts, suggesting the Set1 persists on these RNAs after transcription. This class includes RNAs derived from SET1, Ty1 retrotransposons, specific transcription factors genes and snRNAs. We propose that Set1 modulates adaptive responses, as exemplified by the posttranscriptional inhibition of Ty1 retrotransposition.
Project description:The Set1 family of histone H3 lysine 4 (H3K4) methyltransferases is highly conserved from yeast to humans. Here we show that the Set1 complex (Set1C) directly binds RNA in vitro through the regions that comprise the double RNA recognition motifs (dRRM) and N-SET domain within Set1 and its subunit Spp1. To investigate the functional relevance of RNA binding, we performed UV RNA cross-linking (CRAC) for Set1 and RNA polymerase II in parallel with ChIP-seq experiments. Set1 binds nascent transcripts through its dRRM. RNA binding is important to define the appropriate topology of Set1C distribution along transcription units and correlates with the efficient deposition of the H3K4me3 mark. In addition, we uncovered that Set1 binds to different classes of RNAs to levels that largely exceed the levels of binding to the general population of transcripts, suggesting the Set1 persists on these RNAs after transcription. This class includes RNAs derived from SET1, Ty1 retrotransposons, specific transcription factors genes and snRNAs. We propose that Set1 modulates adaptive responses, as exemplified by the posttranscriptional inhibition of Ty1 retrotransposition.
Project description:We reported the effect of condensin binding to the genome upon SET1 knockdown. ChIP-seq experiments of condensin (NCAPH2) were performed in control and SET1 knockdown cells. We found that condensin binding was significantly reduced upon SET1 knockdown.
Project description:Histone methylation at H3K4 and H3K36 is commonly associated with genes actively transcribed by RNA polymerase II (RNAPII) and is catalyzed by Saccharomyces cerevisiae Set1 and Set2, respectively. Here we report that both methyltransferases can be UV cross-linked to RNA in vivo. High-throughput sequencing of the bound RNAs revealed strong Set1 enrichment near the transcription start site, whereas Set2 was distributed along pre-mRNAs. A subset of transcripts showed notably high enrichment for Set1 or Set2 binding relative to RNAPII, suggesting functional post-transcriptional interactions. In particular, Set1 was strongly bound to the SET1 mRNA, Ty1 retrotransposons, and noncoding RNAs from the ribosomal DNA (rDNA) intergenic spacers, consistent with its previously reported silencing roles. Set1 lacking RNA recognition motif 2 (RRM2) showed reduced in vivo cross-linking to RNA and reduced chromatin occupancy. In addition, levels of H3K4 trimethylation were decreased, whereas levels of dimethylation were increased. We conclude that RNA binding by Set1 contributes to both chromatin association and methyltransferase activity.
Project description:Histone methylation at H3K4 and H3K36 is commonly associated with genes actively transcribed by RNA polymerase II (RNAPII) and is catalyzed by Saccharomyces cerevisiae Set1 and Set2, respectively. Here we report that both methyltransferases can be UV cross-linked to RNA in vivo. High-throughput sequencing of the bound RNAs revealed strong Set1 enrichment near the transcription start site, whereas Set2 was distributed along pre-mRNAs. A subset of transcripts showed notably high enrichment for Set1 or Set2 binding relative to RNAPII, suggesting functional post-transcriptional interactions. In particular, Set1 was strongly bound to the SET1 mRNA, Ty1 retrotransposons, and noncoding RNAs from the ribosomal DNA (rDNA) intergenic spacers, consistent with its previously reported silencing roles. Set1 lacking RNA recognition motif 2 (RRM2) showed reduced in vivo cross-linking to RNA and reduced chromatin occupancy. In addition, levels of H3K4 trimethylation were decreased, whereas levels of dimethylation were increased. We conclude that RNA binding by Set1 contributes to both chromatin association and methyltransferase activity.
Project description:We report the application of the Cross-Linking and cDNA (CRAC) technique to identify binding sites of Npa1, ribosome assembly factors, on RNAs in vivo.
Project description:H3K4me3 is catalyzed by the Set1/MLL family of methyltransferases, whose function in catalyzing H3K4me3 is unique. Impaired function of Set1/MLL family members can lead to many abnormalities, such as bone and nerve defects, leukemia, and even death. Although the Set1 family plays an important regulatory role in various biological processes, it is still unclear how the Set1 protein itself is regulated and how protein levels are maintained. Due to the numerous homologues, complex composition, and high molecular weight of Set1 in higher organisms, especially humans, related research is greatly limited. In brewing yeast, Set1 is the only methyltransferase that catalyzes H3K4me3 and is highly conserved between species. Therefore, yeast is an ideal model for studying the functions and mechanisms of the Set1 family. In addition, Set1 protein plays an important role in regulating gene transcription, promoting telomere silencing, and maintaining cell lifespan. The Set1 family also plays an important regulatory role in the occurrence and development of various cancers.