ID   SHDAG_HDVU2             Reviewed;         195 AA.
AC   Q81835; Q81836;
DT   01-MAR-2004, integrated into UniProtKB/Swiss-Prot.
DT   14-APR-2009, sequence version 2.
DT   29-SEP-2021, entry version 86.
DE   RecName: Full=Small delta antigen;
DE            Short=S-HDAg;
DE   AltName: Full=p24;
OS   Hepatitis delta virus genotype I (isolate US-2) (HDV).
OC   Viruses; Ribozyviria; Kolmioviridae; Deltavirus.
OX   NCBI_TaxID=261991;
OH   NCBI_TaxID=9606; Homo sapiens (Human).
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC RNA], AND RNA EDITING.
RX   PubMed=8415646; DOI=10.1073/pnas.90.19.9016;
RA   Casey J.L., Brown T.L., Colan E.J., Wignall F.S., Gerin J.L.;
RT   "A genotype of hepatitis D virus that occurs in northern South America.";
RL   Proc. Natl. Acad. Sci. U.S.A. 90:9016-9020(1993).
RN   [2]
RP   RNA EDITING.
RX   PubMed=7494266; DOI=10.1128/jvi.69.12.7593-7600.1995;
RA   Casey J.L., Gerin J.L.;
RT   "Hepatitis D virus RNA editing: specific modification of adenosine in the
RT   antigenomic RNA.";
RL   J. Virol. 69:7593-7600(1995).
RN   [3]
RP   RNA EDITING.
RX   PubMed=9528763; DOI=10.1128/mcb.18.4.1919;
RA   Polson A.G., Ley H.L. III, Bass B.L., Casey J.L.;
RT   "Hepatitis delta virus RNA editing is highly specific for the amber/W site
RT   and is suppressed by hepatitis delta antigen.";
RL   Mol. Cell. Biol. 18:1919-1926(1998).
RN   [4]
RP   REVIEW.
RX   PubMed=16402678;
RA   Husa P., Linhartova A., Nemecek V., Husova L.;
RT   "Hepatitis D.";
RL   Acta Virol. 49:219-225(2005).
RN   [5]
RP   REVIEW.
RX   PubMed=16903222; DOI=10.1007/3-540-29802-9_5;
RA   Huang W.H., Chen C.W., Wu H.L., Chen P.J.;
RT   "Post-translational modification of delta antigen of hepatitis D virus.";
RL   Curr. Top. Microbiol. Immunol. 307:91-112(2006).
CC   -!- FUNCTION: Promotes both transcription and replication of genomic RNA.
CC       Following virus entry into host cell, provides nuclear import of HDV
CC       RNPs thanks to its nuclear localization signal. May interact with host
CC       RNA polymerase II thereby changing its template requirement from DNA to
CC       RNA. RNA pol II complex would then acts as an RNA-directed RNA
CC       polymerase, and transcribe and replicate HDV genome (By similarity).
CC       {ECO:0000250}.
CC   -!- SUBUNIT: Homodimer. Homooctamer. Interacts with host RNA polymerase II
CC       complex, and with host NPM1. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Virion. Host nucleus {ECO:0000250}.
CC   -!- PTM: Phosphorylated at serines and threonines by host MAPK1/3, PKR, and
CC       CK2. {ECO:0000250}.
CC   -!- PTM: Acetylation modulates nuclear localization. Neo-synthesized
CC       genomic RNA migrates from the nucleus to the cytoplasm, where they
CC       interact with S-HDAg, which once acetylated redirect both partners to
CC       the nucleus (By similarity). {ECO:0000250}.
CC   -!- PTM: Methylation plays a role in viral genome replication.
CC       {ECO:0000250}.
CC   -!- RNA EDITING: Modified_positions=196 {ECO:0000269|PubMed:7494266,
CC       ECO:0000269|PubMed:8415646, ECO:0000269|PubMed:9528763}; Note=Partially
CC       edited. RNA editing at this position occurs on the antigenomic strand
CC       and consists of a conversion of A to G catalyzed by the cellular enzyme
CC       ADAR1. The unedited RNA version gives rise to the small delta antigen,
CC       which ends with a nonsense codon at position 196. In the edited
CC       version, this amber codon is modified to a tryptophan codon and gives
CC       rise to the large delta antigen protein (AC P0C6M5). S-HDAg suppresses
CC       editing of non-replicating antigenomic RNA, thereby regulating the
CC       extent of editing (By similarity). {ECO:0000250};
CC   -!- MISCELLANEOUS: This strain belongs to the genotype I found in North
CC       America, Europe, Africa, East and West Asia and the South Pacific.
CC   -!- SIMILARITY: Belongs to the hepatitis delta antigen family.
CC       {ECO:0000305}.
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DR   EMBL; L22066; AAB02594.1; -; Genomic_RNA.
DR   SMR; Q81835; -.
DR   PRIDE; Q81835; -.
DR   Proteomes; UP000008235; Genome.
DR   GO; GO:0042025; C:host cell nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0003723; F:RNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0046718; P:viral entry into host cell; IEA:UniProtKB-KW.
DR   GO; GO:0075732; P:viral penetration into host nucleus; IEA:UniProtKB-KW.
DR   Gene3D; 4.10.220.40; -; 1.
DR   InterPro; IPR027403; Delta_antigen_N.
DR   InterPro; IPR037517; HDAG_dom.
DR   InterPro; IPR002506; HDV_ag.
DR   Pfam; PF01517; HDV_ag; 1.
DR   SUPFAM; SSF58108; SSF58108; 1.
DR   PROSITE; PS51838; HDAG; 1.
PE   3: Inferred from homology;
KW   Acetylation; Host nucleus; Host-virus interaction; Methylation;
KW   Phosphoprotein; RNA editing; RNA-binding;
KW   Viral penetration into host nucleus; Virion; Virus entry into host cell.
FT   CHAIN           1..195
FT                   /note="Small delta antigen"
FT                   /id="PRO_0000038151"
FT   DOMAIN          20..195
FT                   /note="HDAg"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01183"
FT   REGION          12..60
FT                   /note="Dimerization"
FT                   /evidence="ECO:0000255"
FT   REGION          52..195
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          97..107
FT                   /note="RNA-binding"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01183"
FT   REGION          130..195
FT                   /note="RNAPII-binding"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01183"
FT   REGION          136..146
FT                   /note="RNA-binding"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01183"
FT   MOTIF           66..75
FT                   /note="Nuclear localization signal"
FT                   /evidence="ECO:0000250|UniProtKB:P0C6L3"
FT   COMPBIAS        57..103
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        118..146
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   MOD_RES         2
FT                   /note="Phosphoserine; by host CK2"
FT                   /evidence="ECO:0000250|UniProtKB:P0C6L3"
FT   MOD_RES         13
FT                   /note="Omega-N-methylated arginine; by host PRMT1"
FT                   /evidence="ECO:0000250|UniProtKB:P0C6L3"
FT   MOD_RES         72
FT                   /note="N6-acetyllysine; by host"
FT                   /evidence="ECO:0000250|UniProtKB:P0C6L3"
FT   MOD_RES         123
FT                   /note="Phosphoserine; by host"
FT                   /evidence="ECO:0000250|UniProtKB:P0C6L3"
FT   MOD_RES         177
FT                   /note="Phosphoserine; by host MAPK1 and MAPK3"
FT                   /evidence="ECO:0000250|UniProtKB:P0C6L3"
FT   MOD_RES         182
FT                   /note="Phosphothreonine; by host"
FT                   /evidence="ECO:0000250|UniProtKB:P0C6L3"
SQ   SEQUENCE   195 AA;  22062 MW;  FC96902761A0AF0E CRC64;
     MSRSESKKNR GGREEILEQW VGARKKLEEL ERDLRKIKKK IKKLEEENPW LGNIKGILGK
     KDREGEGAPP AKRARADQME VDSGPRKRPF RGEFTDKERR DHRRRKALEN KRKQLSSGGK
     SLSKEEEEEL RKLTEEDERR ERRVAGPRVG GVNPLEGGTR GAPGGGFVPS MQGVPESPFA
     RTGEGLDVRG NQGFP