Bloom syndrome protein (BLM)

Bloom syndrome protein (BLM) is a highly conserved ATP-dependent DNA helicase of the RecQ family. It unwinds double-stranded DNA in the 3'-5' direction and is essential for the maintenance of genome integrity. BLM plays a critical role in DNA replication, recombination, and repair, particularly at sites of complex DNA structures such as Holliday junctions. The protein suppresses excess sister chromatid exchanges and unwinds alternative DNA structures—including triple helix and G-quadruplex arrangements—that arise during replication and repair. Mutations in the BLM gene cause Bloom syndrome, a rare inherited disorder defined by high rates of genomic instability, cancer predisposition, immunodeficiency, and premature aging. BLM interacts physically with proteins such as replication protein A (RPA), topoisomerase IIIα, BRCA1, Rad51, and others, coordinating critical aspects of DNA metabolism. Dysregulation or mutation of BLM is directly associated with increased risks for various cancers and is under investigation as a synthetic lethality target for DNA-damaging therapeutics

Other names

Bloom syndrome proteinDNA helicase BLMRecQ-like DNA helicase BLMRecQ protein-like 3RECQ2RECQL3BSMGRISCE1DNA 3'-5' helicase BLM

Drugs causing DNA damage or inhibiting DNA repair may exploit BLM deficiency for synthetic lethality (conceptual approach is similar to PARP inhibitors in BRCA-deficient cancer)