Project description:RNA polymerase II (Pol II) play an essential role in gene expression. Here, we adapted plant Native Elongation Transcript sequencing and Global Run On sequencing to profile nascent RNA genome wide in Arabidopsis. We found Pol II tends to accumulate downstream of transcription start site and pausing at proximal promoter is an important regulatory step for Pol II transcription although loosely controlled. Furthermore, the Pol II with unphosphorylated carboxyl-terminal domain (CTD) mainly accumulates downstream the TSS, while the Ser5P CTD Pol II associates with spliceosome, and the Ser2P CTD Pol II presents a sharp peak 250 base pair downstream of polyadenylation site indicating a stringent control of termination for protein coding genes; whilst the termination of noncoding genes is not. Active expressed genes can be classified into three clusters according to the distribution patterns of different Pol II isoforms. In summary, we demonstrated the modified plant GRO-seq and pNET-seq are suitable to study RNA Pol II dynamics in planta. Although transcription is conserved among high eukaryotes, Pol II has its feature in Arabidopsis.
Project description:The carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) orchestrates dynamic recruitment of specific cellular machines during different stages of transcription. Signature phosphorylation patterns of Y1S2P3T4S5P6S7 heptapeptide repeats of the CTD engage specific “readers.” While phospho-Ser5 and phospho-Ser2 marks are ubiquitous, phospho-Thr4 is reported to only impact specific genes. Here, we investigate the genome-wide occupancy of Pol II, phospho-Thr4, and key reader Rtt103 in WT and CTD-mutant strains of S. cerevisiae.
Project description:RNA polymerase II (Pol II) play an essential role in gene expression. Here, we adapted mammalian Native Elongation Transcript sequencing and Global Run On sequencing to profile nascent RNA genome wide in Arabidopsis. We found Pol II tends to accumulate downstream of transcription start site and pausing at proximal promoter is an important regulatory step for Pol II transcription although loosely controlled. Furthermore, the Pol II with unphosphorylated carboxyl-terminal domain (CTD) mainly accumulates downstream the TSS, while the Ser5P CTD Pol II associates with spliceosome, and the Ser2P CTD Pol II presents a sharp peak 250 base pair downstream of polyadenylation site indicating a stringent control of termination for protein coding genes; whilst the termination of noncoding genes is not. Active expressed genes can be classified into three clusters according to the distribution patterns of different Pol II isoforms. In summary, we demonstrated the modified plant GRO-seq and mNET-seq are suitable to study RNA Pol II dynamics in planta. Although transcription is conserved among high eukaryotes, Pol II has its feature in Arabidopsis.
Project description:Here, we investigated the role of RPAP1 in mammalian cell identity. As in plants, interfering with RPAP1 function did not affect the viability of mouse embryonic stem cells, but severely impaired their differentiation capacity (RNA-Seq#2 data, below). Conversely, in somatic cells, RPAP1 was essential for the expression of lineage specifying factors and viability (RNA-seq#1 data, below). Moreover, inhibition of RPAP1 triggers dedifferentiation and facilitates reprogramming into pluripotent stem cells. Mechanistically, RPAP1 maintains transcribing Pol II levels and Pol II Ser5 phosphorylation, particularly on developmental genes (ChIP-seq data, below).
Project description:Spt6 is a multifunctional histone chaperone involved in the maintenance of chromatin structure during elongation by RNA polymerase II (Pol II). Spt6 has a tandem SH2 (tSH2) domain within its C-terminus that recognizes Pol II CTD peptides phosphorylated on Ser2, Ser5 or Try1 in vitro. Deleting the tSH2 domain, however, only has a partial effect on Spt6 occupancy in vivo, suggesting that more complex mechanisms are involved in the Spt6 recruitment. Our results show that the Ser2 kinases Bur1 and Ctk1, but not the Ser5 kinase Kin28, cooperate in recruiting Spt6, genome-wide. Interestingly, the Ser2 kinases promote the association of Spt6 in early transcribed regions and not toward the 3' end of genes, where phosphorylated Ser2 reaches its maximum level. Additionally, our results uncover an unexpected role for histone deacetylases (Rpd3 and Hos2) in promoting Spt6 interaction with elongating Pol II. Finally, our data suggest that phosphorylation of the Pol II CTD on Tyr1 promotes the association of Spt6 with the 3' end of transcribed genes, independently of Ser2 phosphorylation. Collectively, our results show that a complex network of interactions, involving the Spt6 tSH2 domain, CTD phosphorylation and histone deacetylases, coordinate the recruitment of Spt6 to transcribed genes in vivo.
Project description:The carboxyl-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II) orchestrates dynamic recruitment of specific cellular machines during different stages of transcription. Signature phosphorylation patterns of Y1S2P3T4S5P6S7 heptapeptide repeats of the CTD engage specific “readers.” While phospho-Ser5 and phospho-Ser2 marks are ubiquitous, phospho-Thr4 is reported to only impact specific genes. Here, we investigate the RNA expression profile in WT and CTD-mutant strains of S. cerevisiae.
Project description:RNA polymerase II (Pol II) subunits are thought to be involved in various transcription-associated processes, but it is unclear whether they play different regulatory roles in modulating gene expression. Here, we performed nascent and mature transcript sequencing after the acute degradation of 12 mammalian Pol II subunits and profiled their genomic binding sites and protein interactomes to dissect their molecular functions. We found that Pol II subunits contribute differently to Pol II cellular localization and transcription process and preferentially regulate RNA processing (such as RNA splicing and 3’ end maturation). Genes sensitive to the depletion of different Pol II subunits tend to be involved in diverse biological functions and show different RNA half-lives. Sequences, associated protein factors, and RNA structures are correlated with Pol II subunit-mediated differential gene expression. These findings collectively suggest that the heterogeneity of Pol II and different genes appear to depend on some of the subunits.
Project description:Intronic transposon elements (TEs) comprise a large proportion in eukaryotic genomes, but how they regulate the host genes remains to be explored. Our forward genetic screen disclosed the plant specific RNA polymerases IV and V in suppressing intronic TE-mediated cryptic transcription initiation of a chimeric transcripts at FLC (FLCTE). Initiation of FLCTE transcription is blocked by the locally formed intronic heterochromatin, and RNA Pol V direct associates and establishes intronic heterochromatin, thus inhibits the entry of RNA Pol II Ser5p and the occupancy of H3K4 methylation for promoting initiation. Genome-wide Pol II Ser5p native elongation transcription sequencing revealed that this is a common mechanism among intronic heterochromatin-containing genes. This study sheds light on deeply understanding the function of intronic heterochromatin on host genes expression in eukaryotic genome.
Project description:RNA polymerase II (Pol II) was immunoprecipitated from Arabidopsis thaliana seedlings, using antibodies that specifically recognize: 1) C’ terminal Domain (CTD), 2) CTD Serine 5 Phosphorylation and 3) CTD Serine 2 Phosphorylation. Proteins that co-immunoprecipitate with different Pol II pools were analysed.
Project description:RNA Polymerase II transcribes protein-coding and many non-coding RNA genes in eukaryotes. The largest subunit of RNA Polymerase II, Rpb1, contains a hepta-peptide repeat on its C-terminal tail with three potential phosphorylation sites (Serine 2, Serine 5 and Serine 7). Mammalian Rpb1 contains 52 repeats. The phosphorylation events are catalyzed by specific protein kinases where the phosphorylation of specific residues is coupled to the transcription cycle. For example, the Cdk7 subunit of TFIIH phosphorylates both Serine 5 and Serine 7 during intiation and the Cdk9 subunit of P-TEFb phosphorylates Serine 2 during the transition into productive elongation. The dataset presented here is the genome-wide distribution of RNA Pol II with Serine 7 of the CTD phosphorylated in murine embryonic stem cells. This data, in addition to phospho-specific datasets generated in the same cell type in Rahl et al. Cell 2010 and Seila et al. Science 2008, represents the genome-wide distribution of multiple RNA Pol II isoforms in murine embryonic stem cells: total Pol II, hypophosphorylated CTD Pol II, Serine 2 phosphorylated CTD Pol II, Serine 5 phosphorylated CTD Pol II and Serine 7 phosphorylated CTD Pol II. An antibody specific to RNA Pol II Serine 7 phosphorylated CTD (gift of Dirk Eick; Chapman et al. Science 2008) was used to enrich for DNA fragments associated with this Pol II isoform in murine embryonic stem cells. DNA was purified and prepared for Illumina/Solexa sequencing following their standard protocol. This is a single dataset but together with datasets from Rahl et al. Cell 2010 and Seila et al. Science 2008, these datasets represent the genome-wide distribution of multiple RNA Pol II isoforms in murine embryonic stem cells: total Pol II, hypophosphorylated CTD Pol II, Serine 2 phosphorylated CTD Pol II, Serine 5 phosphorylated CTD Pol II and Serine 7 phosphorylated CTD Pol II.