Polr1b
entrez
20017
canonical
uniprot
P70700
canonical
ensembl
ENSMUSG00000027395
resolver
ensp
ENSMUSP00000099494
resolver
ensp
ENSMUSP00000170818
resolver
enst
ENSMUST00000103205
resolver
genesymbol
Polr1b
resolver
genesymbol_syn
Rpa2
resolver
genesymbol_syn
Rpo1-2
resolver
uniprot
Q3UMX7
resolver
uniprot_entry
RPA2_MOUSE
resolver
uniprot_sec
Q3UMX7
resolver
amino_acid_sequence
MDVDGRWRNLPSGPSLKHLTDPSYGIPPEQQKAALQDLTRAHVDSFNYAALEGLSHAVQAIPPFEFAFKDERISLTIVDAVISPPSVPKGTICKDLNVYPAECRGRKSTYRGRLTADISWAVNGVPKGIIKQFLGYVPIMVKSKLCNLYNLPPRVLIEHHEEAEEMGGYFIINGIEKVIRMLIVPRRNFPIAMVRPKWKSRGLGYTQFGVSMRCVREEHSAVNMNLHYVENGTVMLNFIYRKELFFLPLGFALKALVSFSDYQIFQELIKGKEEDSFFRNSVSQMLRIVIEEGCHSQKQVLNYLGECFRVKLSLPDWYPNVEAAEFLLNQCICIHLQSNTDKFYLLCLMTRKLFALARGECMDDNPDSLVNQEVLSPGQLFLMFLKEKMENWLVSIKIVLDKRAQKANVSINNENLMKIFSMGTELTRPFEYLLATGNLRSKTGLGFLQDSGLCVVADKLNFLRYLSHFRCVHRGAAFAKMRTTTVRRLLPESWGFLCPVHTPDGAPCGLLNHLTAVCEVVTKFVYTASIPALLCGLGVTPVDTAPCRPYSDCYPVLLDGVMVGWVDKDLAPEVADTLRRFKVLREKRIPPWMEVALIPMTGKPSLYPGLFLFTTPCRLVRPVQNLELGREELIGTMEQLFMNVAIFEDEVFGGISTHQELFPHSLLSVIANFIPFSDHNQSPRNMYQCQMGKQTMGFPLLTYQNRSDNKLYRLQTPQSPLVRPCMYDFYDMDNYPIGTNAIVAVISYTGYDMEDAMIVNKASWERGFAHGSVYKSEFIDLSEKFKQGEDNLVFGVKPGDPRVMQKLDDDGLPFIGAKLEYGDPYYSYLNLNTGEGFVVYYKSKENCVVDNIKVCSNDMGSGKFKCICITVRIPRNPTIGDKFASRHGQKGILSRLWPAEDMPFTESGMMPDILFNPHGFPSRMTIGMLIESMAGKSAALHGLCHDATPFIFSEENSALEYFGEMLKAAGYNFYGTERLYSGISGMELEADIFIGVVYYQRLRHMVSDKFQVRTTGARDKVTNQPLGGRNVQGGIRFGEMERDALLAHGTSFLLHDRLFNCSDRSVAHMCVECGSLLSPLLEKPPPSWSAMRNRKYNCTVCGRSDTIDTVSVPYVFRYFVAELAAMNIKVKLDVI
uniprot
proteins
ec_number
2.7.7.6
uniprot
proteins
function
FUNCTION: Catalytic core component of RNA polymerase I (Pol I), a DNA-dependent RNA polymerase which synthesizes ribosomal RNA precursors using the four ribonucleoside triphosphates as substrates. Transcribes 47S pre-rRNAs from multicopy rRNA gene clusters, giving rise to 5.8S, 18S and 28S ribosomal RNAs (By similarity). Pol I-mediated transcription cycle proceeds through transcription initiation, transcription elongation and transcription termination stages. During transcription initiation, Pol I pre-initiation complex (PIC) is recruited by the selectivity factor 1 (SL1/TIF-IB) complex bound to the core promoter that precedes an rDNA repeat unit. The PIC assembly bends the promoter favoring the formation of the transcription bubble and promoter escape. 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. Highly processive, assembles in structures referred to as 'Miller trees' where many elongating Pol I complexes queue and transcribe the same rDNA coding regions. At terminator sequences downstream of the rDNA gene, PTRF interacts with Pol I and halts Pol I transcription leading to the release of the RNA transcript and polymerase from the DNA (By similarity). Forms Pol I active center together with the largest subunit POLR1A/RPA1. Appends one nucleotide at a time to the 3' end of the nascent RNA, with POLR1A/RPA1 contributing a Mg(2+)-coordinating DxDGD motif, and POLR1B/RPA2 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 the 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. Has proofreading activity: Pauses and backtracks to allow the cleavage of a missincorporated nucleotide via POLR1H/RPA12. High Pol I processivity is associated with decreased transcription fidelity (By similarity). {ECO:0000250|UniProtKB:P10964, ECO:0000250|UniProtKB:Q9H9Y6}.
uniprot
proteins
mass_dalton
128213
uniprot
proteins
protein_family
RNA polymerase beta chain family
uniprot
proteins
pubmed
16141072
uniprot
proteins
pubmed
19468303
uniprot
proteins
pubmed
21183079
uniprot
proteins
pubmed
30272023
uniprot
proteins
pubmed
30746471
uniprot
proteins
pubmed
30949703
uniprot
proteins
pubmed
8921381
uniprot
proteins
sequence_length
1135
uniprot
proteins
subcellular_location
SUBCELLULAR LOCATION: Nucleus, nucleolus {ECO:0000250|UniProtKB:Q9H9Y6}. Chromosome {ECO:0000269|PubMed:30272023, ECO:0000269|PubMed:30746471, ECO:0000269|PubMed:30949703}.
uniprot
proteins