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Characterization of RecQL4 biochemical and cellular functions
Author(s) -
Rossi Marie L,
Croteau Deborah L,
Bohr Vilhelm A
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.lb33
Subject(s) - helicase , rna helicase a , dna , cytoplasm , biology , mitochondrion , microbiology and biotechnology , genome instability , atpase , dna damage , genetics , chemistry , biochemistry , rna , enzyme , gene
Three members of the evolutionarily conserved RecQ helicase family important for genome maintenance are linked with human segmental premature aging and cancer: BLM, WRN, and RecQL4. In recent studies, purified human RecQL4 displayed weak helicase activity compared to a strong strand annealing activity, which was only revealed when excess of single stranded DNA was used to trap the released strand. We detect novel ATPase‐driven and strand annealing‐independent RecQL4 unwinding activity on forked duplexes in the absence of excess ssDNA. Additionally, we extend the characterization of human RecQL4 activities to other DNA substrates. We also show that RecQL4's ATPase and unwinding activities are abolished by mutation of the conserved lysine within the helicase domain. Together our results indicate that RecQL4 shares the biochemical activities of the other RecQ helicases. However, unlike the other RecQ helicases, RecQL4 has been reported in both the nucleus and cytoplasm. Recently, using confocal microscopy and fractionated cell extracts, we observed RecQL4 in mitochondria. Therefore, studies have been initiated to investigate interactions between RecQL4 and mitochondrial proteins. This research was supported by funds from the Intramural Research Program of the National Institutes of Health, National Institute on Aging.