ID   RDRP_I82A2              Reviewed;         161 AA.
AC   P26144;
DT   01-MAY-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-1992, sequence version 1.
DT   23-FEB-2022, entry version 71.
DE   RecName: Full=RNA-directed RNA polymerase catalytic subunit;
DE            EC=2.7.7.48;
DE   AltName: Full=Polymerase basic protein 1;
DE            Short=PB1;
DE   AltName: Full=RNA-directed RNA polymerase subunit P1;
DE   Flags: Fragment;
GN   Name=PB1;
OS   Influenza A virus (strain A/Camel/Mongolia/1982 H1N1).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus.
OX   NCBI_TaxID=387191;
OH   NCBI_TaxID=8782; Aves.
OH   NCBI_TaxID=9606; Homo sapiens (Human).
OH   NCBI_TaxID=9823; Sus scrofa (Pig).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=8249279; DOI=10.1006/viro.1993.1629;
RA   Yamnikova S.S., Mandler J., Bekh-Ochir Z.H., Dachtzeren P., Ludwig S.,
RA   Lvov D.K., Scholtissek C.;
RT   "A reassortant H1N1 influenza A virus caused fatal epizootics among camels
RT   in Mongolia.";
RL   Virology 197:558-563(1993).
CC   -!- FUNCTION: RNA-dependent RNA polymerase which is responsible for
CC       replication and transcription of virus RNA segments. The transcription
CC       of viral mRNAs occurs by a unique mechanism called cap-snatching. 5'
CC       methylated caps of cellular mRNAs are cleaved after 10-13 nucleotides
CC       by PA. In turn, these short capped RNAs are used as primers by PB1 for
CC       transcription of viral mRNAs. During virus replication, PB1 initiates
CC       RNA synthesis and copy vRNA into complementary RNA (cRNA) which in turn
CC       serves as a template for the production of more vRNAs.
CC       {ECO:0000250|UniProtKB:P03431}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a ribonucleoside 5'-triphosphate + RNA(n) = diphosphate +
CC         RNA(n+1); Xref=Rhea:RHEA:21248, Rhea:RHEA-COMP:14527, Rhea:RHEA-
CC         COMP:17342, ChEBI:CHEBI:33019, ChEBI:CHEBI:61557, ChEBI:CHEBI:140395;
CC         EC=2.7.7.48; Evidence={ECO:0000255|PROSITE-ProRule:PRU00539};
CC   -!- SUBUNIT: Influenza RNA polymerase is composed of three subunits: PB1,
CC       PB2 and PA. Interacts (via N-terminus) with PA (via C-terminus).
CC       Interacts (via C-terminus) with PB2 (via N-terminus); this interaction
CC       is essential for transcription initiation.
CC       {ECO:0000250|UniProtKB:P03431}.
CC   -!- SUBCELLULAR LOCATION: Host nucleus {ECO:0000250|UniProtKB:P03431}. Host
CC       cytoplasm {ECO:0000250|UniProtKB:P03431}.
CC   -!- PTM: Phosphorylated by host PRKCA. {ECO:0000250|UniProtKB:P03431}.
CC   -!- SIMILARITY: Belongs to the influenza viruses polymerase PB1 family.
CC       {ECO:0000305}.
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DR   EMBL; M73973; AAA16910.1; -; mRNA.
DR   PDB; 1WBZ; X-ray; 2.00 A; P/Q=107-115.
DR   PDBsum; 1WBZ; -.
DR   SMR; P26144; -.
DR   EvolutionaryTrace; P26144; -.
DR   GO; GO:0030430; C:host cell cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0000166; F:nucleotide binding; IEA:UniProtKB-KW.
DR   GO; GO:0003723; F:RNA binding; IEA:InterPro.
DR   GO; GO:0003968; F:RNA-directed 5'-3' RNA polymerase activity; IEA:UniProtKB-KW.
DR   GO; GO:0039523; P:suppression by virus of host mRNA transcription via inhibition of RNA polymerase II activity; IEA:UniProtKB-KW.
DR   GO; GO:0039694; P:viral RNA genome replication; IEA:InterPro.
DR   GO; GO:0019083; P:viral transcription; IEA:UniProtKB-KW.
DR   InterPro; IPR001407; RNA_pol_PB1_influenza.
DR   Pfam; PF00602; Flu_PB1; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Eukaryotic host gene expression shutoff by virus;
KW   Eukaryotic host transcription shutoff by virus; Host cytoplasm;
KW   Host gene expression shutoff by virus; Host nucleus;
KW   Host-virus interaction; Inhibition of host RNA polymerase II by virus;
KW   Nucleotide-binding; Nucleotidyltransferase; Phosphoprotein;
KW   RNA-directed RNA polymerase; Transferase; Viral RNA replication;
KW   Viral transcription.
FT   CHAIN           <1..161
FT                   /note="RNA-directed RNA polymerase catalytic subunit"
FT                   /id="PRO_0000078746"
FT   NON_TER         1
SQ   SEQUENCE   161 AA;  18834 MW;  9F03E097D5AAB8B1 CRC64;
     NLYNIRNLHI PEVCLKWELM DEDYQGRLCN PLNPFVSHKE IESVNNAVMM PAHGPAKNME
     YDAVATTHSW VPKRNRSILN TSQRGILEDE QMYQRCCNLF EKFFPSSSYR RPVGISSMVE
     AMVSRARIDA RIDFESGRIK KEEFTEIMKT CSTIEELRRQ K