Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043346 (xeroderma pigmentosum)
 2,924 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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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PMID:Ca(2+)-mediated inhibition of a nuclear protein that recognizes UV-damaged DNA and is constitutively overexpressed in resistant human cells: DNA-binding assay. 175 77

Microinjection of cell extracts prepared from both human placenta and HeLa cells into xeroderma pigmentosum (XP) cells of complementation group A restores unscheduled DNA synthesis (UDS) in these cells after UV irradiation [de Jonge, A., Vermeulen, W., Klein, B. & Hoeijmakers, J. (1983) EMBO J. 2, 637-641]. These cells also showed normal resistance to UV irradiation. The half-life of the factors in the cell extracts corresponding to the UDS activity (factor A) was 14 hr in XP cells of group A, and the maximal level of UDS was exerted 2 hr after microinjection. The factors were sensitive to protease treatment but not to RNase treatment and were found to be approximately equal to 160 and approximately equal to 90 kDa by gel filtration. These two fractions of the factor(s) acted specifically in XP cells of complementation group A among complementation groups A, B, C, D, F, G, and probably E and H.
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PMID:Microinjection of partially purified protein factor restores DNA damage specifically in group A of xeroderma pigmentosum cells. 345 96

The repair of X-ray-induced DNA damage related to the proliferating cell nuclear antigen (PCNA) was characterized in human diploid fibroblasts by an indirect immunofluorescence method. PCNA staining induced by X rays was lost after DNase I treatment but not after RNase treatment. The staining was not induced when ATP was depleted or the temperature was lowered to 0 degrees C during the X irradiation. When cells were incubated at 37 degrees C after X irradiation, PCNA staining diminished gradually and was almost entirely absent 12-15 h later. On the other hand, PCNA staining persisted during aphidicolin treatment even 20 h after X irradiation. Induction of PCNA staining was not affected by the aphidicolin treatment. Cycloheximide treatment did not affect induction of the staining either, but did inhibit the disappearance of the staining. There was no difference in the staining pattern and time course of PCNA staining after X irradiation between normal and xeroderma pigmentosum group A (XP-A) cells. These results imply that PCNA-dependent, aphidicolin-sensitive DNA polymerases may be involved in repair of X-ray-induced DNA damage in vivo, but the repair initiation step could be different from that of nucleotide excision repair initiated by XP proteins.
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PMID:Characterization of X-ray-induced immunostaining of proliferating cell nuclear antigen in human diploid fibroblasts. 853 40