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FLASH GENE

Symbol

TOP3A

contributors: mct - updated : 11-09-2018

HGNC name	topoisomerase (DNA) III alpha
HGNC id	11992

FLASH GENE DNA RNA EXPRESSION PROTEIN DISORDER ANIMAL & CELL MODELS

EXPRESSION

Type

widely

expressed in	(based on citations)
organ(s)	System Organ level 1 Organ level 2 Organ level 3 Organ level 4 Level Pubmed Species Stage Rna symbol Digestive mouth tongue     highly Lymphoid/Immune thymus       highly   tonsils       highly Reproductive female system uterus cervix   highly

tissue

System Tissue Tissue level 1 Tissue level 2 Level Pubmed Species Stage Rna symbol Muscular striatum skeletal

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)

Type Gene Modification Chromosome rearrangement Protein expression Protein 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	)
	System Type Disorder Pubmed tumor     potential role in dissociating telomeric structures in telomerase-deficient cells, providing therapeutic implications in human tumors

ANIMAL & CELL MODELS