Roles of RECQ helicases in recombination based DNA repair, genomic stability and aging.

The maintenance of the stability of genetic material is an essential feature of every living organism. Organisms across all kingdoms have evolved diverse and highly efficient repair mechanisms to protect the genome from deleterious consequences of various genotoxic factors that might tend to destabilize the integrity of the genome in each generation. One such group of proteins that is actively involved in genome surveillance is the RecQ helicase family. These proteins are highly conserved DNA helicases, which have diverse roles in multiple DNA metabolic processes such as DNA replication, recombination and DNA repair. In humans, five RecQ helicases have been identified and three of them namely, WRN, BLM and RecQL4 have been linked to genetic diseases characterized by genome instability, premature aging and cancer predisposition. This helicase family plays important roles in various DNA repair pathways including protecting the genome from illegitimate recombination during chromosome segregation in mitosis and assuring genome stability. This review mainly focuses on various roles of human RecQ helicases in the process of recombination-based DNA repair to maintain genome stability and physiological consequences of their defects in the development of cancer and premature aging.