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FLASH GENE
Symbol TOP3A contributors: mct - updated : 11-09-2018
HGNC name topoisomerase (DNA) III alpha
HGNC id 11992
Corresponding disease
BLMLS Bloom syndrome-like
Location 17p11.2      Physical location : 18.177.234 - 18.218.321
Synonym name
  • topo III-alpha
  • DNA topoisomerase III alpha
  • Synonym symbol(s) TOP3, ZGRF7, MGRISCE2, PEOB5, TOP3
    EC.number 5.99.1.2
    DNA
    TYPE functioning gene
    STRUCTURE 45.13 kb     19 Exon(s)
    10 Kb 5' upstream gene genomic sequence study
    MAPPING cloned Y linked N status confirmed
    Map see SMCR (phenotype)
    Physical map
    SMCR5 17p11.2 Smith-Magenis syndrome chromosome region, candidate 5 SREBF1 17p11.2 sterol regulatory element binding transcription factor 1 TOM1L2 17p11.2 target of myb1-like 2 (chicken) DKFZP586M1120 17p11.2 hypothetical protein DKFZp586M1120 ATPAF2 17p11.2 ATP synthase mitochondrial F1 complex assembly factor 2 MGC3048 17p11.2 hypothetical protein MGC3048 DRG2 17p11.2 developmentally regulated GTP binding protein 2 MYO15A 17p11.2 myosin XVA FLJ20308 17p11.2 hypothetical protein FLJ20308 LLGL1 17p11.2 lethal giant larvae homolog 1 (Drosophila) FLII 17p11.2 flightless I homolog (Drosophila) SMCR7 17p12 Smith-Magenis syndrome chromosome region, candidate 7 TOP3A 17p11.2 topoisomerase (DNA) III alpha SMCR8 17p11.2 Smith-Magenis syndrome chromosome region, candidate 8 SHMT1 17p11.2 serine hydroxymethyltransferase 1 (soluble) LOC339237 17p11.2 similar to Envoplakin (210 kDa paraneoplastic pemphigus antigen) (p210) (210 kDa cornified envelope precursor) LOC339240 17p11.2 keratin pseudogene LOC339241 17p11.2 keratin pseudogene LOC339242 17p11.2 similar to Keratin, type I cytoskeletal 14 (Cytokeratin 14) (K14) (CK 14) LOC339243 17p11.2 similar to Keratin, type I cytoskeletal 16 (Cytokeratin 16) (K16) (CK 16) LOC339244 17p11.2 keratin pseudogene LOC252968 17p11.2 karyopherin (importin) beta 2 pseudogene LOC147158 17p11.2 lectin, galactoside-binding, soluble, 9 (galectin 9) pseudogene LOC201288 17p11.2 nitric oxide synthase 2A (inducible, hepatocytes) pseudogene LOC220594 17p11.2 TL132 protein FLJ11800 17p11.2 hypothetical protein FLJ11800 LOC252840 17p11.1 signal recognition particle 68kD pseudogene LOC201287 17p11.2 KIAA0565 related gene FLJ36492 17p11.2 hypothetical protein FLJ36492 FLJ40244 17p11.2 hypothetical protein FLJ40244 LOC388345 17 similar to poly(A) binding protein interacting protein 1 isoform 1; polyadenylate binding protein-interacting protein 1; PABC1-interacting protein 1
    regionally located within the Smith-Magenis critical region
    RNA
    TRANSCRIPTS type messenger
    identificationnb exonstypebpproduct
    ProteinkDaAAspecific expressionYearPubmed
    19 - 4116 - 1001 - 2014 24509834
    18 - 6634 - 906 - 2014 24509834
    EXPRESSION
    Type widely
       expressed in (based on citations)
    organ(s)
    SystemOrgan level 1Organ level 2Organ level 3Organ level 4LevelPubmedSpeciesStageRna symbol
    Digestivemouthtongue  highly
    Lymphoid/Immunethymus   highly
     tonsils   highly
    Reproductivefemale systemuteruscervix highly
    tissue
    SystemTissueTissue level 1Tissue level 2LevelPubmedSpeciesStageRna symbol
    Muscularstriatumskeletal  
    cell lineage
    cell lines
    fluid/secretion
    at STAGE
    physiological period pregnancy
    PROTEIN
    PHYSICAL PROPERTIES
    STRUCTURE
    motifs/domains
    HOMOLOGY
    Homologene
    FAMILY
  • prokaryotic type I/III topoisomerase family
  • CATEGORY enzyme
    SUBCELLULAR LOCALIZATION     intracellular
    intracellular,cytoplasm,organelle,mitochondria
    intracellular,nucleus,nucleoplasm,nuclear bodies,PML
    intracellular,nucleus,chromatin/chromosome
    text
  • three different topoisomerases have been identified in mitochondria: TOP1MT, TOP3A and a truncated form of TOP2B
  • basic FUNCTION
  • putatively involved in suppression of mitotic recombination between repetitive sequences
  • catalyzing the transient breaking and rejoining of a single strand of DNA which allows the strands to pass through one another, thus reducing the number of supercoils and altering the topology of DNA
  • important telomere-associated factor, essential for telomere maintenance and chromosome stability
  • is a type IA DNA topoisomerase that functions with BLM and RMI1 to resolve DNA replication and recombination intermediates
  • is involved in DNA repair surveillance and cell-cycle checkpoints possibly through formatting complex with tumor suppressors
  • mitochondrial TOP3A ablation results in mitochondrial genome instability and its dysfunction, thereby accelerating the aging process
  • is an essential component of the mtDNA replication machinery and as the first component of the mtDNA separation machinery
  • CELLULAR PROCESS
    PHYSIOLOGICAL PROCESS
    PATHWAY
    metabolism
    signaling
    a component
  • colocalizing and complexing with BLM
  • combines with the BLM helicase and RMI1 to form an evolutionarily conserved complex, termed the BTB complex
  • BLM forms the BTRR complex with topoisomerase III alpha (TOP3A) and RecQ-mediated genome instability proteins 1 and 2 (RMI1 and RMI2)
  • INTERACTION
    DNA binding
    RNA
    small molecule
    protein
  • binding and interacting with TOP3B
  • ability of RMI1 to interact with BLM and TOP3A is crucial for RMI1 to respond to replication fork stress
  • TDP2 having preferential action at abortive TOP2A and possibly TOP3A cleavage complexes
  • TOP3A binds to the TP53 and CDKN1A promoters and positively regulates their expression, contributing to the TP53-mediated tumor suppression
  • multifaceted role of the TOP3A-RMI1-RMI2 ensemble and of DNA2 in the DNA resection reaction
  • cell & other
    REGULATION
    ASSOCIATED DISORDERS
    corresponding disease(s) BLMLS
    Other morbid association(s)
    TypeGene ModificationChromosome rearrangementProtein expressionProtein Function
    tumoral fusion      
    fused to KMT12A in an adult patient with acute myeloid leukaemia
    Susceptibility
    Variant & Polymorphism
    Candidate gene
  • TOP3A could be a candidate gene involved in human primary immunodeficiency syndrome
  • Marker
    Therapy target )
    SystemTypeDisorderPubmed
    tumor  
    potential role in dissociating telomeric structures in telomerase-deficient cells, providing therapeutic implications in human tumors
    ANIMAL & CELL MODELS