Cell lines from xeroderma pigmentosum complementation group A lack a single-stranded-DNA-binding activity.
Human fibroblasts and HeLa cells contain two major DNA-binding activities for superhelical DNA, which can be separated by phosphocellulose chromatography. The DNA-binding activity which elutes first from the column coelutes with and is probably identical to a single-stranded-DNA-binding activity. The second activity has been characterized previously. It binds preferentially to super-helical DNA containing DNA damage, but does not bind to single-stranded DNA. Five cell lines derived from patients with the repair-deficiency syndrome xeroderma pigmentosum (XP) were analyzed for the presence of these binding activities. Four of the cell lines were from the A-complementation group and one was from the D-complementation group of XP. The binding activity with preference for damaged DNA was present in all cell lines. The single-stranded-DNA-binding activity was present in the XP-D cell line but was absent or reduced in all of the four XP-A cell lines tested.
D000328:Adult; D002460:Cell Line; D002648:Child; D002675:Child, Preschool; D004260:DNA Repair; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000172:deficiency* / Q000235:genetics*; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D005816:Genetic Complementation Test; D006801:Humans; D008297:Male; D014983:Xeroderma Pigmentosum / Q000235:genetics / Q000378:metabolism*
D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins