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Details on Person UniProt:P30876 POLR2B

Class:IdReferenceGeneProduct:63505
_chainChangeLogchain:1-1174 added on Sat February 7 2015
_displayNameUniProt:P30876 POLR2B
_timestamp2026-02-20 21:34:04
chainchain:1-1174
checksum32BEDF7F95E4DE10
commentFUNCTION Catalytic core component of RNA polymerase II (Pol II), a DNA-dependent RNA polymerase which synthesizes mRNA precursors and many functional non-coding RNAs using the four ribonucleoside triphosphates as substrates (By similarity) (PubMed:27193682, PubMed:30190596, PubMed:9852112). Pol II-mediated transcription cycle proceeds through transcription initiation, transcription elongation and transcription termination stages. During transcription initiation, Pol II pre-initiation complex (PIC) is recruited to DNA promoters, with focused-type promoters containing either the initiator (Inr) element, or the TATA-box found in cell-type specific genes and dispersed-type promoters that often contain hypomethylated CpG islands usually found in housekeeping genes. Once the polymerase has escaped from the promoter it enters the elongation phase during which RNA is actively polymerized, based on complementarity with the template DNA strand. Transcription termination involves the release of the RNA transcript and polymerase from the DNA (PubMed:27193682, PubMed:30190596, PubMed:9852112). Forms Pol II active center together with the largest subunit POLR2A/RPB1. Appends one nucleotide at a time to the 3' end of the nascent RNA, with POLR2A/RPB1 most likely contributing a Mg(2+)-coordinating DxDGD motif and POLR2B/RPB2 participating in the coordination of a second Mg(2+) ion and providing lysine residues believed to facilitate Watson-Crick base pairing between the incoming nucleotide and template base. Typically, Mg(2+) ions direct a 5' nucleoside triphosphate to form a phosphodiester bond with the 3' hydroxyl of the preceding nucleotide of the nascent RNA, with the elimination of pyrophosphate. The reversible pyrophosphorolysis can occur at high pyrophosphate concentrations (By similarity) (PubMed:30190596, PubMed:9852112). Can proofread the nascent RNA transcript by means of a 3' -> 5' exonuclease activity. If a ribonucleotide is mis-incorporated, backtracks along the template DNA and cleaves the phosphodiester bond releasing the mis-incorporated 5'-ribonucleotide (By similarity) (PubMed:8381534).FUNCTION RNA-dependent RNA polymerase that catalyzes the extension of a non-coding RNA (ncRNA) at the 3'-end using the four ribonucleoside triphosphates as substrates. An internal ncRNA sequence near the 3'-end serves as a template in a single-round Pol II-mediated RNA polymerization reaction. May decrease the stability of ncRNAs that repress Pol II-mediated gene transcription.CATALYTIC ACTIVITY RNA(n) + a ribonucleoside 5'-triphosphate = RNA(n+1) + diphosphateCATALYTIC ACTIVITY RNA(n) + a ribonucleoside 5'-triphosphate = RNA(n+1) + diphosphateCATALYTIC ACTIVITY a 3'-end ribonucleotidyl-ribonucleotide-RNA + H2O = a 3'-end ribonucleotide-RNA + a ribonucleoside 5'-phosphate + H(+)COFACTOR Two Mg(2+) ions are coordinated by both the catalytic residues and the nucleic acid substrate to enhance substrate recognition and catalytic efficiency.ACTIVITY REGULATION Pol II enzymatic activities are inhibited by alpha-amanitin. 3'->5' exonuclease activity is stimulated by TFIIS, whereas pyrophosphorolysis is enhanced by TFIIF.SUBUNIT Component of the RNA polymerase II (Pol II) core complex consisting of 12 subunits: a ten-subunit catalytic core composed of POLR2A/RPB1, POLR2B/RPB2, POLR2C/RPB3, POLR2I/RPB9, POLR2J/RPB11, POLR2E/RPABC1, POLR2F/RPABC2, POLR2H/RPABC3, POLR2K/RPABC4 and POLR2L/RPABC5 and a mobile stalk composed of two subunits POLR2D/RPB4 and POLR2G/RPB7, protruding from the core and functioning primarily in transcription initiation. Part of Pol II(G) complex, in which Pol II core associates with an additional subunit POLR2M; unlike conventional Pol II, Pol II(G) functions as a transcriptional repressor. Part of TBP-based Pol II pre-initiation complex (PIC), in which Pol II core assembles with general transcription factors and other specific initiation factors including GTF2E1, GTF2E2, GTF2F1, GTF2F2, TCEA1, ERCC2, ERCC3, GTF2H2, GTF2H3, GTF2H4, GTF2H5, GTF2A1, GTF2A2, GTF2B and TBP; this large multi-subunit PIC complex mediates DNA unwinding and targets Pol II core to the transcription start site where the first phosphodiester bond forms (PubMed:27193682, PubMed:30190596, PubMed:9852112). Interacts with WDR82 (PubMed:14992727, PubMed:17998332). Interacts with MEN1 (PubMed:14992727).INTERACTION Belongs to the RNA polymerase beta chain family.
descriptionrecommendedName: DNA-directed RNA polymerase II subunit RPB2 ecNumber evidence="5 6 8"2.7.7.6 alternativeName: 3'-5' exoribonuclease ecNumber evidence="7"3.1.13.- alternativeName: DNA-directed RNA polymerase II 140 kDa polypeptide alternativeName: DNA-directed RNA polymerase II subunit B alternativeName: RNA polymerase II subunit 2 alternativeName: RNA polymerase II subunit B2 alternativeName: RNA-directed RNA polymerase II subunit RPB2 ecNumber evidence="4"2.7.7.48
geneNamePOLR2B
identifierP30876
isSequenceChangedFALSE
keyword3D-structure
DNA-directed RNA polymerase
Hydrolase
Magnesium
Metal-binding
Methylation
Nucleotidyltransferase
Nucleus
Phosphoprotein
Proteomics identification
Reference proteome
RNA-directed RNA polymerase
Transcription
Transferase
Zinc
Zinc-finger
modified[InstanceEdit:9836292] Weiser, Joel, 2023-05-25
[InstanceEdit:9852000] Weiser, Joel, 2023-11-03
[InstanceEdit:9909836] Weiser, Joel, 2024-05-14
[InstanceEdit:9917590] Weiser, Joel, 2024-08-09
[InstanceEdit:9926675] Weiser, Joel, 2024-11-03
[InstanceEdit:9939033] Weiser, Joel, 2025-02-21
[InstanceEdit:9983091] Weiser, Joel, 2026-02-20
namePOLR2B
referenceDatabase[ReferenceDatabase:2] UniProt
referenceGene[ReferenceDNASequence:8988636] ENSEMBL:ENSG00000047315 POLR2B [Homo sapiens]
secondaryIdentifierRPB2_HUMAN
A8K1A8
Q8IZ61
sequenceLength1174
species[Species:48887] Homo sapiens
(referenceEntity)[EntityWithAccessionedSequence:63504] POLR2B [nucleoplasm] [Homo sapiens]
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