6gmh | pdb_00006gmh
Structure of activated transcription complex Pol II-DSIF-PAF-SPT6
Structural highlights
Function[I3LGP4_PIG] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[RuleBase:RU363031] [SPT4H_HUMAN] component of the drb sensitivity-inducing factor complex (dsif complex), which regulates mrna processing and transcription elongation by rna polymerase ii dsif positively regulates mrna capping by stimulating the mrna guanylyltransferase activity of rngtt/cap1a dsif also acts cooperatively with the negative elongation factor complex (nelf complex) to enhance transcriptional pausing at sites proximal to the promoter transcriptional pausing may facilitate the assembly of an elongation competent rna polymerase ii complex dsif and nelf promote pausing by inhibition of the transcription elongation factor tfiis/s-ii tfiis/s-ii binds to rna polymerase ii at transcription pause sites and stimulates the weak intrinsic nuclease activity of the enzyme cleavage of blocked transcripts by rna polymerase ii promotes the resumption of transcription from the new 3' terminus and may allow repeated attempts at transcription through natural pause sites dsif can also positively regulate transcriptional elongation and is required for the efficient activation of transcriptional elongation by the hiv- 1 nuclear transcriptional activator, tat dsif acts to suppress transcriptional pausing in transcripts derived from the hiv-1 ltr and blocks premature release of hiv-1 transcripts at terminator sequences [SPT5H_HUMAN] Component of the DRB sensitivity-inducing factor complex (DSIF complex), which regulates mRNA processing and transcription elongation by RNA polymerase II. DSIF positively regulates mRNA capping by stimulating the mRNA guanylyltransferase activity of RNGTT/CAP1A. DSIF also acts cooperatively with the negative elongation factor complex (NELF complex) to enhance transcriptional pausing at sites proximal to the promoter. Transcriptional pausing may facilitate the assembly of an elongation competent RNA polymerase II complex. DSIF and NELF promote pausing by inhibition of the transcription elongation factor TFIIS/S-II. TFIIS/S-II binds to RNA polymerase II at transcription pause sites and stimulates the weak intrinsic nuclease activity of the enzyme. Cleavage of blocked transcripts by RNA polymerase II promotes the resumption of transcription from the new 3' terminus and may allow repeated attempts at transcription through natural pause sites. DSIF can also positively regulate transcriptional elongation and is required for the efficient activation of transcriptional elongation by the HIV-1 nuclear transcriptional activator, Tat. DSIF acts to suppress transcriptional pausing in transcripts derived from the HIV-1 LTR and blocks premature release of HIV-1 transcripts at terminator sequences.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [SPT6H_HUMAN] Transcription elongation factor which binds histone H3 and plays a key role in the regulation of transcription elongation and mRNA processing. Enhances the transcription elongation by RNA polymerase II (RNAPII) and is also required for the efficient activation of transcriptional elongation by the HIV-1 nuclear transcriptional activator, Tat. Besides chaperoning histones in transcription, acts to transport and splice mRNA by forming a complex with IWS1 and the C-terminal domain (CTD) of the RNAPII subunit RPB1 (POLR2A). The SUPT6H:IWS1:CTD complex recruits mRNA export factors (ALYREF/THOC4, EXOSC10) as well as histone modifying enzymes (such as SETD2), to ensure proper mRNA splicing, efficient mRNA export and elongation-coupled H3K36 methylation, a signature chromatin mark of active transcription. SUPT6H via its association with SETD1A, regulates both class-switch recombination and somatic hypermutation through formation of H3K4me3 epigenetic marks on activation-induced cytidine deaminase (AICDA) target loci. Promotes the activation of the myogenic gene program by entailing erasure of the repressive H3K27me3 epigenetic mark through stabilization of the chromatin interaction of the H3K27 demethylase KDM6A.[20] [21] [22] [23] [24] [RPB9_PIG] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Component of RNA polymerase II which synthesizes mRNA precursors and many functional non-coding RNAs. Pol II is the central component of the basal RNA polymerase II transcription machinery. It is composed of mobile elements that move relative to each other. RPB9 is part of the upper jaw surrounding the central large cleft and thought to grab the incoming DNA template (By similarity). [WDR61_HUMAN] Component of the PAF1 complex (PAF1C) which has multiple functions during transcription by RNA polymerase II and is implicated in regulation of development and maintenance of embryonic stem cell pluripotency. PAF1C associates with RNA polymerase II through interaction with POLR2A CTD non-phosphorylated and 'Ser-2'- and 'Ser-5'-phosphorylated forms and is involved in transcriptional elongation, acting both indepentently and synergistically with TCEA1 and in cooperation with the DSIF complex and HTATSF1. PAF1C is required for transcription of Hox and Wnt target genes. PAF1C is involved in hematopoiesis and stimulates transcriptional activity of KMT2A/MLL1; it promotes leukemogenesis through association with KMT2A/MLL1-rearranged oncoproteins, such as KMT2A/MLL1-MLLT3/AF9 and KMT2A/MLL1-MLLT1/ENL. PAF1C is involved in histone modifications such as ubiquitination of histone H2B and methylation on histone H3 'Lys-4' (H3K4me3). PAF1C recruits the RNF20/40 E3 ubiquitin-protein ligase complex and the E2 enzyme UBE2A or UBE2B to chromatin which mediate monoubiquitination of 'Lys-120' of histone H2B (H2BK120ub1); UB2A/B-mediated H2B ubiquitination is proposed to be coupled to transcription. PAF1C is involved in mRNA 3' end formation probably through association with cleavage and poly(A) factors. In case of infection by influenza A strain H3N2, PAF1C associates with viral NS1 protein, thereby regulating gene transcription. Required for mono- and trimethylation on histone H3 'Lys-4' (H3K4me3), dimethylation on histone H3 'Lys-79' (H3K4me3). Required for Hox gene transcription. Component of the SKI complex which is thought to be involved in exosome-mediated RNA decay and associates with transcriptionally active genes in a manner dependent on PAF1C.[25] [26] [27] [28] [I3LCB2_PIG] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Common component of RNA polymerases I, II and III which synthesize ribosomal RNA precursors, mRNA precursors and many functional non-coding RNAs, and small RNAs, such as 5S rRNA and tRNAs, respectively.[PIRNR:PIRNR000779] Publication Abstract from PubMedGene regulation involves activation of RNA polymerase II (Pol II) that is paused and bound by the protein complexes DRB sensitivity-inducing factor (DSIF) and negative elongation factor (NELF). Here we show that formation of an activated Pol II elongation complex in vitro requires the kinase function of the positive transcription elongation factor b (P-TEFb) and the elongation factors PAF1 complex (PAF) and SPT6. The cryo-EM structure of an activated elongation complex of Sus scrofa Pol II and Homo sapiens DSIF, PAF and SPT6 was determined at 3.1 A resolution and compared to the structure of the paused elongation complex formed by Pol II, DSIF and NELF. PAF displaces NELF from the Pol II funnel for pause release. P-TEFb phosphorylates the Pol II linker to the C-terminal domain. SPT6 binds to the phosphorylated C-terminal-domain linker and opens the RNA clamp formed by DSIF. These results provide the molecular basis for Pol II pause release and elongation activation. Structure of activated transcription complex Pol II-DSIF-PAF-SPT6.,Vos SM, Farnung L, Boehning M, Wigge C, Linden A, Urlaub H, Cramer P Nature. 2018 Aug;560(7720):607-612. doi: 10.1038/s41586-018-0440-4. Epub 2018 Aug, 22. PMID:30135578[29] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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