Deficiency in a helicase of the RecQ family is found in at least three human genetic disorders associated with cancer predisposition and/or premature ageing. The RecQ helicases encoded by the BLM, WRN and RECQ4 genes are defective in Bloom's, Werner's and Rothmund-Thomson syndromes, respectively. Cells derived from individuals with these disorders in each case show inherent genomic instability....

RecQ helicases are key genome maintenance enzymes that function in DNA replication, recombination, and repair. In contrast to nearly every other identified RecQ family member, the RecQ helicase from the radioresistant bacterium Deinococcus radiodurans encodes three "Helicase and RNase D C-terminal" (HRDC) domains at its C terminus. HRDC domains have been implicated in structure-specific nucleic...

RecQ helicases are involved in the processing of DNA structures arising during replication, recombination, and repair throughout all kingdoms of life. Mutations of different RecQ homologues are responsible for severe human diseases, such as Blooms (BLM) or Werner (WRN) syndrome. The loss of RecQ function is often accompanied by hyperrecombination caused by a lack of crossover suppression. In th...

The RecQ helicases are a highly conserved family of DNA-unwinding enzymes that play key roles in protecting the genome stability in all kingdoms of life. Human RecQ homologs include RECQ1, BLM, WRN, RECQ4, and RECQ5β. Although the individual RecQ-related diseases are characterized by a variety of clinical features encompassing growth defects (Bloom Syndrome and Rothmund Thomson Syndrome) to pre...

Even a partial loss of function of human RecQ helicase analogs causes adverse effects such as a cancer-prone Werner, Bloom or Rothmund-Thompson syndrome, whereas a complete RecQ deficiency in Escherichia coli is not deleterious for a cell. We show that this puzzling difference is due to different mechanisms of DNA double strand break (DSB) resection in E. coli and humans. Coupled helicase and R...

RecQ family helicases play important roles at G-rich domains of the genome, including the telomeres, rDNA, and immunoglobulin switch regions. This appears to reflect the unusual ability of enzymes in this family to unwind G4 DNA. How RecQ family helicases recognize this substrate has not been established. Here, we show that G4 DNA is a preferred target for BLM helicase within the context of lon...

Genomic instability leads to mutations, cellular dysfunction and aberrant phenotypes at the tissue and organism levels. A number of mechanisms have evolved to cope with endogenous or exogenous stress to prevent chromosomal instability and maintain cellular homeostasis. DNA helicases play important roles in the DNA damage response. The RecQ family of DNA helicases is of particular interest since...

The archaeal Hjm is a structure-specific DNA helicase, which was originally identified in the hyperthermophilic archaeon, Pyrococcus furiosus, by in vitro screening for Holliday junction migration activity. Further biochemical analyses of the Hjm protein from P. furiosus showed that this protein preferably binds to fork-related Y-structured DNAs and unwinds their double-stranded regions in vitr...

Helicases are molecular motor proteins that couple the hydrolysis of NTP to nucleic acid unwinding. The growing number of DNA helicases implicated in human disease suggests that their vital specialized roles in cellular pathways are important for the maintenance of genome stability. In particular, mutations in genes of the RecQ family of DNA helicases result in chromosomal instability diseases ...

RecQ helicases have essential roles in maintaining genome stability during replication and in controlling double-strand break repair by homologous recombination. Little is known about how the different RecQ helicases found in higher eukaryotes achieve their specialized and partially opposing functions. Here, we investigate the DNA unwinding of RecQ helicases from Arabidopsis thaliana, AtRECQ2 a...