Project description:Nuclear pores associate with active protein-coding genes in yeast and have been implicated in transcriptional regulation. Here, we show that in addition to transcriptional regulation, key components of C. elegans nuclear pores are required for processing of a subset of small nucleolar RNAs (snoRNAs) and tRNAs transcribed by RNA Polymerase (Pol) III. Chromatin immunoprecipitation of NPP-13 and NPP-3, two integral nuclear pore components, and importin-ß IMB-1, provides strong evidence that this requirement is direct. All three proteins associate specifically with tRNA and snoRNA genes undergoing Pol III transcription. These pore components bind immediately downstream of the Pol III pre-initiation complex, but are not required for Pol III recruitment. Instead, NPP-13 is required for cleavage of tRNA and snoRNA precursors into mature RNAs, whereas Pol II transcript processing occurs normally. Our data suggest that integral nuclear pore proteins act to coordinate transcription and processing of Pol III transcripts in C. elegans.
Project description:Nuclear pores associate with active protein-coding genes in yeast and have been implicated in transcriptional regulation. Here, we show that in addition to transcriptional regulation, key components of C. elegans nuclear pores are required for processing of a subset of small nucleolar RNAs (snoRNAs) and tRNAs transcribed by RNA Polymerase (Pol) III. Chromatin immunoprecipitation of NPP-13 and NPP-3, two integral nuclear pore components, and importin-ß IMB-1, provides strong evidence that this requirement is direct. All three proteins associate specifically with tRNA and snoRNA genes undergoing Pol III transcription. These pore components bind immediately downstream of the Pol III pre-initiation complex, but are not required for Pol III recruitment. Instead, NPP-13 is required for cleavage of tRNA and snoRNA precursors into mature RNAs, whereas Pol II transcript processing occurs normally. Our data suggest that integral nuclear pore proteins act to coordinate transcription and processing of Pol III transcripts in C. elegans.
Project description:Nuclear pores associate with active protein-coding genes in yeast and have been implicated in transcriptional regulation. Here, we show that in addition to transcriptional regulation, key components of C. elegans nuclear pores are required for processing of a subset of small nucleolar RNAs (snoRNAs) and tRNAs transcribed by RNA Polymerase (Pol) III. Chromatin immunoprecipitation of NPP-13 and NPP-3, two integral nuclear pore components, and importin-M-CM-^_ IMB-1, provides strong evidence that this requirement is direct. All three proteins associate specifically with tRNA and snoRNA genes undergoing Pol III transcription. These pore components bind immediately downstream of the Pol III pre-initiation complex, but are not required for Pol III recruitment. Instead, NPP-13 is required for cleavage of tRNA and snoRNA precursors into mature RNAs, whereas Pol II transcript processing occurs normally. Our data suggest that integral nuclear pore proteins act to coordinate transcription and processing of Pol III transcripts in C. elegans. Genome-wide ChIP-seq and ChIP-chip were performed in mixed-stage C. elegans embryos for nuclear pore proteins NPP-13, NPP-3, IMB-1 and chromatin proteins Pol III (RPC-1), TBP-1, TFC-1 (SFC-1), TFC-4 (TAG-315), and Pol II (AMA-1). For RPC-1 and TBP-1 ChIP-seq, embryos depleted for NPP-13 were also used. Total RNAs from wild-type, NPP-13 RNAi, and IMB-1 RNAi embryos were analyzed by RNA-seq.
Project description:Nuclear pores associate with active protein-coding genes in yeast and have been implicated in transcriptional regulation. Here, we show that in addition to transcriptional regulation, key components of C. elegans nuclear pores are required for processing of a subset of small nucleolar RNAs (snoRNAs) and tRNAs transcribed by RNA Polymerase (Pol) III. Chromatin immunoprecipitation of NPP-13 and NPP-3, two integral nuclear pore components, and importin-M-CM-^_ IMB-1, provides strong evidence that this requirement is direct. All three proteins associate specifically with tRNA and snoRNA genes undergoing Pol III transcription. These pore components bind immediately downstream of the Pol III pre-initiation complex, but are not required for Pol III recruitment. Instead, NPP-13 is required for cleavage of tRNA and snoRNA precursors into mature RNAs, whereas Pol II transcript processing occurs normally. Our data suggest that integral nuclear pore proteins act to coordinate transcription and processing of Pol III transcripts in C. elegans. Genome-wide ChIP-seq and ChIP-chip were performed in mixed-stage C. elegans embryos for nuclear pore proteins NPP-13, NPP-3, IMB-1 and chromatin proteins Pol III (RPC-1), TBP-1, TFC-1 (SFC-1), TFC-4 (TAG-315), and Pol II (AMA-1). For RPC-1 and TBP-1 ChIP-seq, embryos depleted for NPP-13 were also used. Total RNAs from wild-type, NPP-13 RNAi, and IMB-1 RNAi embryos were analyzed by RNA-seq.
Project description:Transcription of the eukaryotic genomes is carried out by three distinct RNA polymerases I, II and III whereby each polymerase is thought to independently transcribe a distinct set of genes. To investigate a possible relationship of RNA polymerases II and III we mapped their in vivo binding sites throughout the human genome using ChIP Seq in two different cell lines, GM12878 and K562 cells. Pol III was found to bind near many known genes as well as several novel genes. RNA-Seq studies indicate that majority of the genes are expressed although a subset are not suggestive of stalling by RNA polymerase III. Pol II was found to bind near many known Pol III genes, including tRNA, U6, HVG, hY and 7SK and novel Pol III genes. Similarly, in vivo binding studies also reveal that a number of transcription factors normally associated with Pol II transcription, including c-Fos, c-Jun and c-Myc, also tightly associate with most Pol III transcribed genes. Inhibition of Pol II activity using ?-amanitin reduced expression of a number of Pol III genes (e.g. U6, hY, HVG), suggesting that Pol II plays an important role in regulating their transcription. These results indicate that, contrary to previous expectations, polymerases can often work with one another to globally coordinate gene expression. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf This SuperSeries is composed of the SubSeries listed below.
Project description:RNA polymerase (RNA Pol) III synthesizes the tRNAs, the 5S ribosomal RNA and a small number of untranslated RNAs. In vitro, it also transcribes short interspersed nuclear elements (SINEs). We investigated the distribution of RNA Pol III and its associated transcription factors on the genome of mouse embryonic stem (ES) cell using a highly specific tandem ChIP-Seq method. Only a subset of the annotated class-III genes was bound and thus transcribed. A few hundred SINEs were associated with the RNA Pol III transcription machinery. We observed that RNA Pol III and its transcription factors were present at thirty unannotated sites on the mouse genome, only one of which was conserved in human. An RNA was associated with more than 80% of these regions. More than 2200 regions bound by TFIIIC transcription factor were devoid of RNA Pol III. These sites are correlated with association of CTCF and the cohesin. Cohesin has been shown to occupy sites bound by CTCF and to contribute to DNA loop formation associated with gene repression or activation. This observation suggests that TFIIIC may play a role in chromosome organization in mouse. We also investigated the genome-wide distribution of the ubiquitous TFIIS variant, TCEA1. We found that, as in Saccharomyces cerevisiae, TFIIS is associated with class III genes and also with SINEs suggesting that TFIIS is a RNA Pol III transcription factor in mammals. We performed ChIP-seq experiment on mouse ES cells, in order to analyse the distribution of the RNA Pol III, with two of its subunits, RPC1 and RPC4, of the two distinct forms of the transcription factor TFIIIB, with BRF1 and BRF2, respectively subunit of TFIIIB-beta, and TFIIIB-alpha form, and three subunits of the transcription factor TFIIIC, TFIIIC90, TFIIIC110, TFIIIC220. We also analysed the distribution of the RNA Pol II elongation factor TCEA1. We used tagged proteins, in order to develop a highly specific and generic ChIP-seq protocol. A sequence encoding a 6 histidine-Flag-HA tag was inserted just after the last codon of the gene encoding proteins of the RNA Pol III machinery subunits, or just after the start codon for TCEA1, using the recombineering technology. Untagged ES cell line was used as negative control for data processing. Our dataset comprises of ten ChIP-seq samples, eight from tagged proteins, two from untagged cell line.
Project description:MAF1 represses Pol III-mediated transcription by interfering with TFIIIB and Pol III. Herein, we found that MAF1 knockdown induced CDKN1A transcription and chromatin looping concurrently with Pol III recruitment. Simultaneous knockdown of MAF1 with Pol III or BRF1 (subunit of TFIIIB) diminished the activation and looping effect, which indicates that recruiting Pol III was required for activation of Pol II-mediated transcription and chromatin looping. ChIP analysis after MAF1 knockdown indicated enhanced binding of Pol III and BRF1, as well as of CFP1, p300, and PCAF, which are factors that mediate active histone marks, along with the binding of TBP and POLR2E to the CDKN1A promoter. Simultaneous knockdown with Pol III abolished these regulatory events. Similar results were obtained for GDF15. Our results reveal a novel mechanism by which MAF1 and Pol III regulate the activity of a protein-coding gene transcribed by Pol II.
Project description:RNA polymerase (Pol) III transcribes many noncoding RNAs (for example, transfer RNAs) important for translational capacity and other functions. We localized Pol III, alternative TFIIIB complexes (BRF1 or BRF2) and TFIIIC in HeLa cells to determine the Pol III transcriptome, define gene classes and reveal 'TFIIIC-only' sites. Pol III localization in other transformed and primary cell lines reveals previously uncharacterized and cell type–specific Pol III loci as well as one microRNA. Notably, only a fraction of the in silico–predicted Pol III loci are occupied. Many occupied Pol III genes reside within an annotated Pol II promoter. Outside of Pol II promoters, occupied Pol III genes overlap with enhancer-like chromatin and enhancer-binding proteins such as ETS1 and STAT1. Moreover, Pol III occupancy scales with the levels of nearby Pol II, active chromatin and CpG content. These results suggest that active chromatin gates Pol III accessibility to the genome.
Project description:Particularly in the context of differentiation and development, the importance of three-dimensional chromatin architecture to gene regulatory mechanisms is becoming increasingly clear. The most ancient known mechanism of chromatin organization involves TFIIIC, a transcription factor (TF) that recruits RNA polymerase III (Pol III) for transcription of tRNA and other types of non-coding RNA genes. From yeast to mammals, TFIIIC binds to tRNA genes (tDNAs) and scattered “extra-TFIIIC” (ETC) loci and serves to tether these loci together as anchors of chromatin loops. TFIIIC activities are modulated by MAF, MYC, and other TF proteins that are still unidentified. Here we identify the ZSCAN5 TF family - including mammalian ZSCAN5B and its primate-specific paralogs - as proteins that occupy mammalian Pol III promoters and ETC sites. We show that ZSCAN5B binds with high specificity to a conserved subset of tDNA loci and other Pol III genes in human and mouse and that primate-specific ZSCAN5A and ZSCAN5D also bind Pol III genes, although ZSCAN5D preferentially localizes to MIR SINE- and LINE2-associated ETC sites. ZSCAN5 genes are expressed in proliferating cell populations and are cell-cycle regulated, and gene expression data suggested that they might cooperate to regulate basic cellular functions including mitotic progression. Consistent with this predicted role, ZSCAN5A knockdown led to increasing numbers of cells in mitotic cells and aneuploidy in cultured cells. Together these data implicate ZSCAN5 genes in regulation of Pol III gene transcription and nearby Pol II genes, ultimately influencing cell cycle progression and differentiation in a variety of tissues.