ID   RDRP_I77AD              Reviewed;         757 AA.
AC   P16512;
DT   01-AUG-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1990, sequence version 1.
DT   08-NOV-2023, entry version 89.
DE   RecName: Full=RNA-directed RNA polymerase catalytic subunit {ECO:0000255|HAMAP-Rule:MF_04065};
DE            EC=2.7.7.48 {ECO:0000255|HAMAP-Rule:MF_04065};
DE   AltName: Full=Polymerase basic protein 1 {ECO:0000255|HAMAP-Rule:MF_04065};
DE            Short=PB1 {ECO:0000255|HAMAP-Rule:MF_04065};
DE   AltName: Full=RNA-directed RNA polymerase subunit P1 {ECO:0000255|HAMAP-Rule:MF_04065};
GN   Name=PB1 {ECO:0000255|HAMAP-Rule:MF_04065};
OS   Influenza A virus (strain A/Swine/Tennessee/26/1977 H1N1).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus;
OC   Alphainfluenzavirus influenzae; Influenza A virus.
OX   NCBI_TaxID=384479;
OH   NCBI_TaxID=8782; Aves.
OH   NCBI_TaxID=9606; Homo sapiens (Human).
OH   NCBI_TaxID=9823; Sus scrofa (Pig).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RX   PubMed=2795713; DOI=10.1128/jvi.63.11.4603-4608.1989;
RA   Kawaoka Y., Krauss S., Webster R.G.;
RT   "Avian-to-human transmission of the PB1 gene of influenza A viruses in the
RT   1957 and 1968 pandemics.";
RL   J. Virol. 63:4603-4608(1989).
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:0000255|HAMAP-Rule:MF_04065}.
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|HAMAP-Rule:MF_04065};
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. Interacts (via C-terminus)
CC       with human PKP2 (via N-terminus); the interaction competitively
CC       inhibits the interaction between the RNA polymerase subunits PB1 and
CC       PB2 (By similarity). {ECO:0000250|UniProtKB:P03431, ECO:0000255|HAMAP-
CC       Rule:MF_04065}.
CC   -!- SUBCELLULAR LOCATION: Host nucleus {ECO:0000255|HAMAP-Rule:MF_04065}.
CC       Host cytoplasm {ECO:0000255|HAMAP-Rule:MF_04065}.
CC   -!- PTM: Phosphorylated by host PRKCA. {ECO:0000255|HAMAP-Rule:MF_04065}.
CC   -!- SIMILARITY: Belongs to the influenza viruses polymerase PB1 family.
CC       {ECO:0000255|HAMAP-Rule:MF_04065}.
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DR   EMBL; M25931; AAA43640.1; -; Genomic_RNA.
DR   SMR; P16512; -.
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-UniRule.
DR   GO; GO:0003723; F:RNA binding; IEA:InterPro.
DR   GO; GO:0003968; F:RNA-dependent RNA polymerase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0006351; P:DNA-templated transcription; IEA:UniProtKB-UniRule.
DR   GO; GO:0039523; P:suppression by virus of host mRNA transcription via inhibition of RNA polymerase II activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0039694; P:viral RNA genome replication; IEA:UniProtKB-UniRule.
DR   GO; GO:0019083; P:viral transcription; IEA:UniProtKB-KW.
DR   Gene3D; 6.10.140.720; -; 1.
DR   HAMAP; MF_04065; INFV_RDRP; 1.
DR   InterPro; IPR007099; RNA-dir_pol_NSvirus.
DR   InterPro; IPR001407; RNA_pol_PB1_influenza.
DR   Pfam; PF00602; Flu_PB1; 1.
DR   PIRSF; PIRSF000827; RdRPol_OMV; 1.
DR   PROSITE; PS50525; RDRP_SSRNA_NEG_SEG; 1.
PE   3: Inferred from homology;
KW   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..757
FT                   /note="RNA-directed RNA polymerase catalytic subunit"
FT                   /id="PRO_0000078771"
FT   DOMAIN          286..483
FT                   /note="RdRp catalytic"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04065"
FT   REGION          52..78
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          249..256
FT                   /note="Promoter-binding site"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04065"
FT   MOTIF           187..195
FT                   /note="Nuclear localization signal"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04065"
FT   MOTIF           203..216
FT                   /note="Nuclear localization signal"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04065"
SQ   SEQUENCE   757 AA;  86344 MW;  C8DB0DA2959C67BD CRC64;
     MDVNPTLLFL KVPAQNAIST TFPYTGDPPY SHGTGTGYTM DTVNRTHQYS ERGKWTTNTE
     TGAPQLNPID GPLPEDNEPT GYAQTDCVLE AMAFLEKSHP GIFENSCLET MEVVQQTRVD
     KLTQGRQTFD WTLNRNQPAA TALANTIEVF RLNGLTASES GRLIDFLKDV MESMDKEEME
     IVTHFQRKRR VRDNMTKKMV TQRTIGKKKQ KLNKRSYIIR ALTLNTMTKD AERGKLKRRA
     IATPGMQIRG FVYFVETLAR SICEKLEQSG LPVGGNEKKA KLANVVRKMM TNSQDTELSF
     TITGDNTKWN ENQNPRMFLA MITYITRNQP EWFRNVLSIA PIMFSNKMAR LGKGYMFESK
     NMKLRTQIPA EMLSGIDLRY FNDSTRKKIE KIRPLLIDGA ASLSPGMMMG MFNMLSTVLG
     VSILNLGQKE YTKTAYWWDG LQSSDDFALI VNALNHEGIQ AGVDRFYRTC KLLGINMSKK
     KSYINRTGTF EFTSFFYRYG FVANFSMELP SFGVSGINES ADMSIGVTVI KNNMINNDLG
     PATAQMALQL FIKDYRYTYR CHRGDTQIQT RRSFEIKKLW DQTHSKAGLL VSDGGPNLYN
     IRNLHIPEVC LKWELMDKDY QGRLCNPLNP FVSHKEIESV NNAVVMPSHG PAKTMEYDAV
     ATTHSWVPKR NRSILNTSQR GILEDEQMYQ KCCNLFEKFF PSSSYRRPVG ISSMVEAMVS
     RARIDARIDF ESGRIKKEDF AEIMKICSTI EDLRRQK
//