Localization of a gene involved in complementation of the defect in xeroderma pigmentosum group A cells on human chromosome 1.
Human, Chinese hamster or Chinese hamster/human hybrid cytoplasts were fused with UV-irradiated xeroderma pigmentosum group A (XP-A) cells. Unscheduled DNA synthesis (UDS) of the XP-A nucleus was measured 0-2 and 2-4 h after seeding of the fused population. Human cytoplasts did correct the defect in the XP-A nucleus immediately after fusion, whereas the chinese hamster cytoplasts did not show this rapid increase in excision repair. The results obtained after fusion of cytoplasts isolated from a panel of 26 Chinese hamster-human hybrids showed that chromosome 1 bears genetic information that is necessary for the rapid correction of the XP-A defect. Furthermore, this genetic information was regionally assigned to 1q42-qter by analysing hybrid cell lines having retained various segments of chromosome 1. Cytoplasts from a Chinese hamster/XP-A hybrid containing chromosome 1 of XP-A origin corrected also the defect with fast kinetics. This result indicate that the correcting factor consists of human and Chinese hamster components. As a consequence, the gene mapped on chromosome 1 may not be the gene which is mutated in XP-A cells.
D002459:Cell Fusion; D002478:Cells, Cultured; D002874:Chromosome Mapping; D002878:Chromosomes, Human, Pair 1; D004260:DNA Repair; D004261:DNA Replication; D005347:Fibroblasts / Q000166:cytology / Q000528:radiation effects; D005796:Genes; D005816:Genetic Complementation Test; D006801:Humans; D014176:Protein Biosynthesis; D012867:Skin / Q000166:cytology / Q000473:pathology; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000235:genetics*