Ca(2+)-mediated inhibition of a nuclear protein that recognizes UV-damaged DNA and is constitutively overexpressed in resistant human cells: DNA-binding assay.
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| Abstract |
A nuclear protein that recognizes UV-damaged DNA was detected from HeLa cells using DNA-binding assay. Treatment of cells with Ca2+ ionophore (A23187) caused a dramatic inhibition of the damage-recognition activity. In contrast, in vitro treatment of nuclear extracts with agents that affect protein conformation (such as urea, NP40 and Ca2+) did not significantly affect on the damage-recognition activity. The Ca(2+)-mediated inhibition of UV damage recognition was reconstituted by the addition of the cytosolic extracts, suggesting that the Ca2+ effect does not directly act on the UV damage-recognition protein. The expression of the detected nuclear protein was increased in UV-resistant HeLa cells. In contrast, the level of this protein was dramatically reduced in UV-sensitive xeroderma pigmentosum group A cells. In addition, UV damage-recognition protein is resistant to RNase, and is independent of the previously identified proteins that bind cisplatin-DNA adduct. These findings implied that the recognition of UV-DNA adduct is modulated by the intracellular level of Ca2+.
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| Authors | C C Chao, S L Huang, S Lin-Chao |
| Journal | Nucleic acids research (Nucleic Acids Res) Vol. 19 Issue 23 Pg. 6413-8 (Dec 11 1991) ISSN: 0305-1048 [Print] England |
| PMID | 1754377 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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