Genomic instability is a known precursor to cancer and aging. The RecQ helicases are a highly conserved family of DNA-unwinding enzymes that play key roles in maintaining genome stability in all living organisms. Human RecQ homologs include RECQ1, BLM, WRN, RECQ4, and RECQ5β, three of which have been linked to diseases with elevated risk of cancer and growth defects (Bloom Syndrome and Rothmund...

RecQ helicases are members of an evolutionary conserved family of DNA helicases. They are homologous to the RecQ helicase of E. coli, the founding member of the family. These enzymes include gene products of disease-causing genes in Bloom, Werner, and Rothmund-Thomson syndrome. To date, these proteins have been implicated in many aspects of DNA metabolism, including DNA replication, repair, and...

Helicases are specialized molecular motors that separate duplex nucleic acids into single strands. The RecQ family of helicases functions at the interface of DNA replication, recombination and repair in bacterial and eukaryotic cells. They are key, multifunctional enzymes that have been linked to three human diseases: Bloom's, Werner's and Rothmund-Thomson's syndromes. This review summarizes re...

Bloom syndrome (BS) is characterized by genomic instability and cancer susceptibility caused by defects in BLM, a DNA helicase of the RecQ-family (J. German and N. A. Ellis, The Genetic Basis of Human Cancer, pp. 301-316, 1998). RecQ helicases and topoisomerase III proteins interact physically and functionally in yeast (S. Gangloff et al., Mol. Cell. Biol., 14: 8391-8398, 1994) and in Escherich...

Bloom syndrome (BS) is rare autosomal recessive disorder associated with chromosomal instability. The gene responsible for BS, BLM, encodes a protein belonging to the RecQ helicase family. Disruptions of the SGS1 gene of Saccharomyces cerevisiae, which encodes the RecQ helicase homologue in the budding yeast, causes accelerated aging, and this phenotype is enhanced by the disruption of MGS1, th...

Three (BLM, WRN, and RECQ4) of the five human RecQ helicases are linked to genetic disorders characterized by genomic instability, cancer, and accelerated aging [1]. RECQ1, the first human RecQ helicase discovered [2-4] and the most abundant [5], was recently implicated in breast cancer [6, 7]. RECQ1 is an ATP-dependent DNA-unwinding enzyme (helicase) [8, 9] with roles in replication [10-12] an...

RecQ DNA helicases are key enzymes in the maintenance of genome integrity, and they have functions in DNA replication, recombination, and repair. In contrast to most RecQs, RecQ from Deinococcus radiodurans (DrRecQ) possesses an unusual domain architecture that is crucial for its remarkable ability to repair DNA. Here, we determined the crystal structures of the DrRecQ helicase catalytic core a...

Members of the RecQ helicase subfamily are mutated in several human genomic instability syndromes, such as Bloom, Werner, and Rothmund-Thomson syndromes. We show that Rqh1, the single Schizosaccharomyces pombe homologue, is a 3'-to-5' helicase and exists with Top3 in a high-molecular-weight complex. top3 deletion is inviable, and this is suppressed by concomitant loss of rqh1 helicase activity ...

Cells must continuously repair inevitable DNA damage while avoiding the deleterious consequences of imprecise repair. Distinction between legitimate and illegitimate repair processes is thought to be achieved in part through differential recognition and processing of specific noncanonical DNA structures, although the mechanistic basis of discrimination remains poorly defined. Here, we show that...