ID   TOP1_CAEEL              Reviewed;         806 AA.
AC   O17966; O17965; Q27529;
DT   29-APR-2008, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1998, sequence version 1.
DT   27-MAR-2024, entry version 157.
DE   RecName: Full=DNA topoisomerase 1;
DE            EC=5.6.2.1 {ECO:0000255|PROSITE-ProRule:PRU10130};
DE   AltName: Full=DNA topoisomerase I;
DE            Short=topoI;
GN   Name=top-1; ORFNames=M01E5.5;
OS   Caenorhabditis elegans.
OC   Eukaryota; Metazoa; Ecdysozoa; Nematoda; Chromadorea; Rhabditida;
OC   Rhabditina; Rhabditomorpha; Rhabditoidea; Rhabditidae; Peloderinae;
OC   Caenorhabditis.
OX   NCBI_TaxID=6239;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA] (ISOFORM A).
RC   STRAIN=Bristol N2;
RX   PubMed=8647074; DOI=10.1111/j.1432-1033.1996.00367.x;
RA   Kim J., Kim Y.-C., Lee J.H., Jang Y.J., Chung I.K., Koo H.-S.;
RT   "cDNA cloning, expression, and chromosomal localization of Caenorhabditis
RT   elegans DNA topoisomerase I.";
RL   Eur. J. Biochem. 237:367-372(1996).
RN   [2]
RP   SEQUENCE REVISION, ALTERNATIVE SPLICING, AND DEVELOPMENTAL STAGE.
RC   STRAIN=Bristol N2;
RX   PubMed=9540836; DOI=10.1016/s0167-4781(97)00209-1;
RA   Lee M.H., Jang Y.J., Koo H.-S.;
RT   "Alternative splicing in the Caenorhabditis elegans DNA topoisomerase I
RT   gene.";
RL   Biochim. Biophys. Acta 1396:207-214(1998).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Bristol N2;
RX   PubMed=9851916; DOI=10.1126/science.282.5396.2012;
RG   The C. elegans sequencing consortium;
RT   "Genome sequence of the nematode C. elegans: a platform for investigating
RT   biology.";
RL   Science 282:2012-2018(1998).
RN   [4]
RP   FUNCTION, SUBCELLULAR LOCATION, TISSUE SPECIFICITY, DEVELOPMENTAL STAGE,
RP   AND DISRUPTION PHENOTYPE.
RX   PubMed=16943775; DOI=10.1038/nature05050;
RA   Chu D.S., Liu H., Nix P., Wu T.F., Ralston E.J., Yates J.R. III,
RA   Meyer B.J.;
RT   "Sperm chromatin proteomics identifies evolutionarily conserved fertility
RT   factors.";
RL   Nature 443:101-105(2006).
CC   -!- FUNCTION: Releases the supercoiling and torsional tension of DNA
CC       introduced during the DNA replication and transcription by transiently
CC       cleaving and rejoining one strand of the DNA duplex. Introduces a
CC       single-strand break via transesterification at a target site in duplex
CC       DNA. The scissile phosphodiester is attacked by the catalytic tyrosine
CC       of the enzyme, resulting in the formation of a DNA-(3'-phosphotyrosyl)-
CC       enzyme intermediate and the expulsion of a 5'-OH DNA strand. The free
CC       DNA strand then rotates around the intact phosphodiester bond on the
CC       opposing strand, thus removing DNA supercoils. Finally, in the
CC       religation step, the DNA 5'-OH attacks the covalent intermediate to
CC       expel the active-site tyrosine and restore the DNA phosphodiester
CC       backbone (By similarity). Required for normal spermatogenesis and
CC       oogenesis (PubMed:16943775). {ECO:0000250|UniProtKB:Q13472,
CC       ECO:0000269|PubMed:16943775}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=ATP-independent breakage of single-stranded DNA, followed by
CC         passage and rejoining.; EC=5.6.2.1; Evidence={ECO:0000255|PROSITE-
CC         ProRule:PRU10130};
CC   -!- SUBCELLULAR LOCATION: Nucleus {ECO:0000250|UniProtKB:P11387}. Nucleus,
CC       nucleolus {ECO:0000269|PubMed:16943775}. Chromosome
CC       {ECO:0000269|PubMed:16943775}. Note=Localizes around sperm chromatids.
CC       {ECO:0000269|PubMed:16943775}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative splicing; Named isoforms=2;
CC       Name=a;
CC         IsoId=O17966-1; Sequence=Displayed;
CC       Name=b;
CC         IsoId=O17966-2; Sequence=VSP_033045;
CC   -!- TISSUE SPECIFICITY: Expressed in male germ cells and in mature sperm.
CC       {ECO:0000269|PubMed:16943775}.
CC   -!- DEVELOPMENTAL STAGE: Isoform a: only expressed in embryos
CC       (PubMed:9540836). Isoform b: present at all developmental stages
CC       (PubMed:9540836). Not expressed during spermatocyte meiosis
CC       (PubMed:16943775). {ECO:0000269|PubMed:16943775,
CC       ECO:0000269|PubMed:9540836}.
CC   -!- DISRUPTION PHENOTYPE: RNAi-mediated knockdown causes abnormal gonad
CC       morphology, enlarged sperm nuclei and aberrant progression through
CC       meiosis. Oocytes appear to have undergone endomitotic reduplication.
CC       {ECO:0000269|PubMed:16943775}.
CC   -!- MISCELLANEOUS: Eukaryotic topoisomerase I and II can relax both
CC       negative and positive supercoils, whereas prokaryotic enzymes relax
CC       only negative supercoils. {ECO:0000250}.
CC   -!- MISCELLANEOUS: [Isoform b]: Predominant isoform. {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the type IB topoisomerase family. {ECO:0000305}.
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DR   EMBL; X96762; CAA65537.1; -; mRNA.
DR   EMBL; Z93385; CAB07639.1; -; Genomic_DNA.
DR   EMBL; Z93385; CAB07640.1; -; Genomic_DNA.
DR   PIR; S65469; S65469.
DR   PIR; T23647; T23647.
DR   PIR; T23648; T23648.
DR   RefSeq; NP_001021578.1; NM_001026407.5.
DR   RefSeq; NP_493337.1; NM_060936.5. [O17966-1]
DR   AlphaFoldDB; O17966; -.
DR   SMR; O17966; -.
DR   BioGRID; 57335; 14.
DR   STRING; 6239.M01E5.5a.2; -.
DR   EPD; O17966; -.
DR   PaxDb; 6239-M01E5-5a; -.
DR   PeptideAtlas; O17966; -.
DR   EnsemblMetazoa; M01E5.5a.1; M01E5.5a.1; WBGene00006595. [O17966-1]
DR   EnsemblMetazoa; M01E5.5b.1; M01E5.5b.1; WBGene00006595. [O17966-2]
DR   GeneID; 266847; -.
DR   KEGG; cel:CELE_M01E5.5; -.
DR   UCSC; M01E5.5b; c. elegans. [O17966-1]
DR   AGR; WB:WBGene00006595; -.
DR   WormBase; M01E5.5a; CE12282; WBGene00006595; top-1. [O17966-1]
DR   WormBase; M01E5.5b; CE12284; WBGene00006595; top-1. [O17966-2]
DR   eggNOG; KOG0981; Eukaryota.
DR   GeneTree; ENSGT00940000167650; -.
DR   HOGENOM; CLU_009193_0_1_1; -.
DR   InParanoid; O17966; -.
DR   OMA; HRWKEVK; -.
DR   OrthoDB; 10940at2759; -.
DR   PhylomeDB; O17966; -.
DR   Reactome; R-CEL-4615885; SUMOylation of DNA replication proteins.
DR   PRO; PR:O17966; -.
DR   Proteomes; UP000001940; Chromosome I.
DR   Bgee; WBGene00006595; Expressed in germ line (C elegans) and 5 other cell types or tissues.
DR   GO; GO:0005694; C:chromosome; IEA:UniProtKB-SubCell.
DR   GO; GO:0005730; C:nucleolus; IDA:WormBase.
DR   GO; GO:0005634; C:nucleus; IDA:WormBase.
DR   GO; GO:0031616; C:spindle pole centrosome; IDA:WormBase.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0003917; F:DNA topoisomerase type I (single strand cut, ATP-independent) activity; IDA:WormBase.
DR   GO; GO:0007059; P:chromosome segregation; IBA:GO_Central.
DR   GO; GO:0006260; P:DNA replication; IBA:GO_Central.
DR   GO; GO:0006265; P:DNA topological change; IBA:GO_Central.
DR   CDD; cd00659; Topo_IB_C; 1.
DR   CDD; cd03488; Topoisomer_IB_N_htopoI_like; 1.
DR   Gene3D; 1.10.132.10; -; 1.
DR   Gene3D; 2.170.11.10; DNA Topoisomerase I, domain 2; 1.
DR   Gene3D; 1.10.10.41; Yeast DNA topoisomerase - domain 1; 1.
DR   InterPro; IPR011010; DNA_brk_join_enz.
DR   InterPro; IPR013034; DNA_topo_DNA_db_N_dom1.
DR   InterPro; IPR013030; DNA_topo_DNA_db_N_dom2.
DR   InterPro; IPR001631; TopoI.
DR   InterPro; IPR018521; TopoI_AS.
DR   InterPro; IPR025834; TopoI_C_dom.
DR   InterPro; IPR014711; TopoI_cat_a-hlx-sub_euk.
DR   InterPro; IPR014727; TopoI_cat_a/b-sub_euk.
DR   InterPro; IPR013500; TopoI_cat_euk.
DR   InterPro; IPR008336; TopoI_DNA-bd_euk.
DR   InterPro; IPR036202; TopoI_DNA-bd_euk_N_sf.
DR   InterPro; IPR013499; TopoI_euk.
DR   InterPro; IPR048045; Topoisomer_I_DNA-bd.
DR   PANTHER; PTHR10290:SF23; DNA TOPOISOMERASE 1; 1.
DR   PANTHER; PTHR10290; DNA TOPOISOMERASE I; 1.
DR   Pfam; PF14370; Topo_C_assoc; 1.
DR   Pfam; PF01028; Topoisom_I; 1.
DR   Pfam; PF02919; Topoisom_I_N; 1.
DR   PRINTS; PR00416; EUTPISMRASEI.
DR   SMART; SM00435; TOPEUc; 1.
DR   SUPFAM; SSF56349; DNA breaking-rejoining enzymes; 1.
DR   SUPFAM; SSF46596; Eukaryotic DNA topoisomerase I, dispensable insert domain; 1.
DR   SUPFAM; SSF56741; Eukaryotic DNA topoisomerase I, N-terminal DNA-binding fragment; 1.
DR   PROSITE; PS00176; TOPO_IB_1; 1.
DR   PROSITE; PS52038; TOPO_IB_2; 1.
PE   2: Evidence at transcript level;
KW   Alternative splicing; Chromosome; DNA-binding; Isomerase; Nucleus;
KW   Reference proteome; Topoisomerase.
FT   CHAIN           1..806
FT                   /note="DNA topoisomerase 1"
FT                   /id="PRO_0000330482"
FT   DOMAIN          474..803
FT                   /note="Topo IB-type catalytic"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01382"
FT   REGION          1..236
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          467..468
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   REGION          530..535
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   REGION          634..636
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   COMPBIAS        1..21
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        22..100
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        151..188
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        213..236
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   ACT_SITE        761
FT                   /note="O-(3'-phospho-DNA)-tyrosine intermediate"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01382,
FT                   ECO:0000255|PROSITE-ProRule:PRU10130"
FT   SITE            358
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            406
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            454
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            485
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            543
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            581
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            623
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            681
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   SITE            699
FT                   /note="Interaction with DNA"
FT                   /evidence="ECO:0000250"
FT   VAR_SEQ         134..205
FT                   /note="Missing (in isoform b)"
FT                   /evidence="ECO:0000305"
FT                   /id="VSP_033045"
FT   CONFLICT        172
FT                   /note="E -> K (in Ref. 1; CAA65537)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   806 AA;  94030 MW;  5979AD386DEBD004 CRC64;
     MSVVSNHHSN GNGNSTVYDT NGNDEIKKEV KDEPMASDSE VPFGELMKRD KKEKKQKKRK
     AESGSDEDDY KPEKRKSSAK NGKKKDVGSD SEDDYKPEKK KSKKNNKKKA QESSEDDDEE
     SEGDVSEEDV KPQIHSDDEL EEEDEAPTTD DEEEQKRKEK ERRKKEKREK KERKEKKRLE
     KENRKIKEED DEDSDDEDDE KAKKKKRKSK GAEKSKPSTS KKDAGGKKEP PKKKVKKEED
     IEDIWEWWKE EKKPAGVKWN SLQHCGPLFA PPYIPLPSHV HFKYGGEKMK LTLETEEIAQ
     FYAGVLDHEY STKEAFNKNF MKDWRKVMTV EERERIHDLK KCDFRAIDAY QKEQREIRKA
     MTKEEKLKIK EEKEAEVKIY GIAIIDGHRQ KVANFRIEPP GVFRGRGGHP KMGLIKKRIM
     PEDVIINCGK DTEIPKPPPG HKWKEVRHDN TVTWLCSWTE SVLGQNKYIM LNPSSKIKGE
     KDFEKYETAR RLKKKIGGIR ERYTDDFKSK EMRVRQRATA LYFIDKLALR AGNEKDVDEA
     ADTVGCCSLR VEHIKLFDSA KLNEDDKKEK EFVVEFDFLG KDSIRYFNRV SVEKRVYKNL
     KIFMEGKAPS DDLFDRLDTA TLNDHLRSLM DGLTVKVFRT YNASITLQEQ LIKLTNPKDN
     VAAKILSYNR ANRQVAILCN HQRAVSKGFD ESMQKLEQKI KDKKKEVKEA EAALKSARGA
     EKEKAQKKYD RLKEQLKKLK ISRTDKDENK QIALGTSKLN YIDPRITVAW CKKFEVPLEK
     VFTKTHREKF RWAIDMTNSS DEEYVF
//