Human xeroderma pigmentosum group G gene encodes a DNA endonuclease.
Because of defective nucleotide excision repair of ultraviolet damaged DNA, xeroderma pigmentosum (XP) patients suffer from a high incidence of skin cancers. Cell fusion studies have identified seven XP complementation groups, A to G. Previous studies have implicated the products of these seven XP genes in the recognition of ultraviolet-induced DNA damage and in incision of the damage-containing DNA strand. Here, we express the XPG-encoded protein in Sf9 insect cells and purify it to homogeneity. We demonstrate that XPG is a single-strand specific DNA endonuclease, thus identifying the catalytic role of the protein in nucleotide excision repair. We suggest that XPG nuclease acts on the single-stranded region created as a result of the combined action of the XPB helicase and XPD helicase at the DNA damage site.
Habraken
Y
Y
Sealy Center for Molecular Science, UTMB, Galveston, TX 77555-1061.
Sung
P
P
Prakash
L
L
Prakash
S
S
D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D002413:Cations, Divalent; D004249:DNA Damage; D004265:DNA Helicases / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D006801:Humans; D015151:Immunoblotting; D007163:Immunosorbent Techniques; D008274:Magnesium / Q000494:pharmacology; D009036:Moths; D011994:Recombinant Proteins; D014162:Transfection; D014983:Xeroderma Pigmentosum / Q000235:genetics*
D002413:Cations, Divalent; D004278:DNA, Superhelical; D011994:Recombinant Proteins; D003850:Deoxyribonuclease I; D004265:DNA Helicases; D008274:Magnesium