ID   RDRP_I45A0              Reviewed;         757 AA.
AC   A4U6W0;
DT   05-MAY-2009, integrated into UniProtKB/Swiss-Prot.
DT   15-MAY-2007, sequence version 1.
DT   23-FEB-2022, entry version 52.
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/USA:Huston/AA/1945 H1N1).
OC   Viruses; Riboviria; Orthornavirae; Negarnaviricota; Polyploviricotina;
OC   Insthoviricetes; Articulavirales; Orthomyxoviridae; Alphainfluenzavirus.
OX   NCBI_TaxID=425551;
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].
RA   Ghedin E., Spiro D., Miller N., Zaborsky J., Feldblyum T., Subbu V.,
RA   Shumway M., Sparenborg J., Groveman L., Halpin R., Sitz J., Koo H.,
RA   Salzberg S.L., Webster R.G., Hoffmann E., Krauss S., Naeve C., Bao Y.,
RA   Bolotov P., Dernovoy D., Kiryutin B., Lipman D.J., Tatusova T.;
RT   "The NIAID influenza genome sequencing project.";
RL   Submitted (APR-2007) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA].
RG   The NIAID Influenza Genome Sequencing Consortium;
RL   Submitted (APR-2007) to the EMBL/GenBank/DDBJ databases.
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. {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; CY021715; ABP49335.1; -; Viral_cRNA.
DR   SMR; A4U6W0; -.
DR   Proteomes; UP000008433; Genome.
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-directed 5'-3' RNA polymerase activity; 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:0006351; P:transcription, DNA-templated; 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   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_0000373050"
FT   DOMAIN          286..483
FT                   /note="RdRp catalytic"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_04065"
FT   REGION          52..81
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;  86575 MW;  77D0FA36B4BFD89F CRC64;
     MDVNPILLFL KVPAQNAIST TFPYTGDPPY SHGTGTGYTM DTVNRTHQYS ERGKWTTNTE
     TGAPQLNPID GPLPEDNEPS GYAQTDCVLE AMAFLEESHP GIFENSCIET MEVVQQTRVD
     KLTQGRQTYD WTLNRNQPAA TALANTIEVF RSNGLTANES GRLIDFLKDV MESMDKEEIE
     ITTHFQRKRR VRDNVTKKMV TQRTIGKRKQ RLNKRSYLIR ALTLNTMTKD AERGKLKRRA
     IATPGMQIRG FVYFVETLAR SICEKLEQSG LPVGGNEKKA KLANVVRKMM TNSQDTEISF
     TITGDNTKWN ENQNPRMFLA MITYITRTQP EWFRNVLSIA PIMFSNKMAR LGKGYMFESK
     SMKLRTQIPA EMLANIDLKY FNDSTRKKIE KIRPLLIDGT ASLSPGMMMG MFNMLSTVLG
     VSILNLGQKR YTKTTYWWDG LQSSDDFALI VNAPNHEGIQ AGVDRFYRTC KLLGINMSKK
     KSYINRTGTF EFTSFFYRYG FVANFSMELP SFGVSGINES ADMSIGVTVI KNNMINNDLG
     PATAQMALQL FIKDYRYTYR CHRGDTQIQT RRSFEIKKLW EQTRSKAGLL VSDGGPNLYN
     IRNLHIPEVC LKWELMDEDY QGRLCNPLNP FVSHKEIESV NNAVMMPAHG PAKNMEYDAV
     ATTHSWIPKR NRSILNTSQR GILEDEQMYQ RCCNLFEKFF PSSSYRRPVG ISSMVEAMVS
     RARIDARIDF ESGRIKKEEF TEIMKICSTI EELRRQK