ID   BEL1_SFV1               Reviewed;         308 AA.
AC   P29169;
DT   01-DEC-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-JUL-1993, sequence version 2.
DT   03-AUG-2022, entry version 71.
DE   RecName: Full=Protein Bel-1;
DE   AltName: Full=Transactivator of spumavirus;
DE            Short=Tas;
DE   AltName: Full=Transcriptional transactivator;
GN   Name=bel1; Synonyms=taf, tas;
OS   Simian foamy virus type 1 (SFVmac) (SFV-1).
OC   Viruses; Riboviria; Pararnavirae; Artverviricota; Revtraviricetes;
OC   Ortervirales; Retroviridae; Spumaretrovirinae; Spumavirus.
OX   NCBI_TaxID=338478;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
OH   NCBI_TaxID=9539; Macaca (macaques).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1647358; DOI=10.1016/0378-1119(91)90410-d;
RA   Kupiec J.-J., Kay A., Hayat M., Ravier R., Peries J., Galibert F.;
RT   "Sequence analysis of the simian foamy virus type 1 genome.";
RL   Gene 101:185-194(1991).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1851862; DOI=10.1128/jvi.65.6.2903-2909.1991;
RA   Mergia A., Shaw K.E.S., Pratt-Lowe E., Barry P.A., Luciw P.A.;
RT   "Identification of the simian foamy virus transcriptional transactivator
RT   gene (taf).";
RL   J. Virol. 65:2903-2909(1991).
CC   -!- FUNCTION: Transcriptional transactivator that activates the viral
CC       internal promoter (IP), thereby enhancing its own expression. This
CC       transactivation is repressed by nuclear factor I. Also transactivates
CC       the long terminal repeat (LTR) promoter, thereby inducing structural
CC       gene expression, initiating the late phase of infection. It is
CC       therefore a key regulator of viral gene expression. It directly binds
CC       to and activates DNA target sites of viral promoters and those of
CC       distinct cellular genes. Required for viral replication (By
CC       similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Homodimer or homomultimer. Forms complexes with the host
CC       nuclear factors NFIA, NFIB, NFIC or NFIX (By similarity).
CC       {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Host nucleus {ECO:0000250}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative splicing; Named isoforms=2;
CC       Name=Bel-1;
CC         IsoId=P29169-1; Sequence=Displayed;
CC       Name=Bet;
CC         IsoId=P29169-2; Sequence=Not described;
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DR   EMBL; X54482; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; M74039; AAA47802.1; -; Genomic_DNA.
DR   PIR; B39924; WMLJS1.
DR   PIR; S18740; S18740.
DR   RefSeq; YP_001961124.1; NC_010819.1.
DR   Proteomes; UP000007216; Genome.
DR   GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0045893; P:positive regulation of transcription, DNA-templated; IEA:InterPro.
DR   GO; GO:0016032; P:viral process; IEA:InterPro.
DR   InterPro; IPR004956; Foamy_BEL.
DR   Pfam; PF03274; Foamy_BEL; 1.
PE   3: Inferred from homology;
KW   Activator; Alternative splicing; DNA-binding; Host nucleus; Transcription;
KW   Transcription regulation.
FT   CHAIN           1..308
FT                   /note="Protein Bel-1"
FT                   /id="PRO_0000125510"
FT   DNA_BIND        94..203
FT                   /evidence="ECO:0000255"
FT   REGION          200..242
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          228..304
FT                   /note="Transactivation domain"
FT                   /evidence="ECO:0000255"
FT   MOTIF           217..226
FT                   /note="Nuclear localization signal"
FT                   /evidence="ECO:0000250"
FT   COMPBIAS        203..227
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
SQ   SEQUENCE   308 AA;  35311 MW;  7E280B6EFB21D992 CRC64;
     MASWEAQEEL RELLHHLPED DPPADLTHLL ELDEMEPKVL CGENPGDEKL KKQVIKTPPM
     HPSTVTWHFG YKQKEDQQDN IKMRDWVPDP SKMSKSTCKR LILLGLYQAC KAQEIIKMDY
     DVHWEKSVVN EQYFEVEYNC KMCRTVLHEP MPIMYDPETE LWVKPGRLRG PLGSAVYTLK
     KHYERCLLTL PSLKGTRLPK RRCNPSRRYE TFREHPPTRK RRSKEGIPTD QQPSTSNGDP
     MALLSGPCGP HSIQPPSCLL QELPKPEVGS PEMAVAMSGG PFWEEVYGDS IFATPLGSSE
     DQLLSQFD