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Microinjection of human cell extracts corrects xeroderma pigmentosum defect.
Author(s) -
Jonge A.J.,
Vermeulen W.,
Klein B.,
Hoeijmakers J.H.
Publication year - 1983
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1983.tb01477.x
Subject(s) - xeroderma pigmentosum , biology , microinjection , genetics , dna , microbiology and biotechnology , dna repair
Cultured fibroblasts of patients with the DNA repair syndrome xeroderma pigmentosum (XP) were injected with crude cell extracts from various human cells. Injected fibroblasts were then assayed for unscheduled DNA synthesis (UDS) to see whether the injected extract could complement their deficiency in the removal of u.v.‐induced thymidine dimers from their DNA. Microinjection of extracts from repair‐proficient cells (such as HeLa, placenta) and from cells belonging to XP complementation group C resulted in a temporary correction of the DNA repair defect in XP‐A cells but not in cells from complementation groups C, D or F. Extracts prepared from XP‐A cells were unable to correct the XP‐A repair defect. The UDS of phenotypically corrected XP‐A cells is u.v.‐specific and can reach the level of normal cells. The XP‐A correcting factor was found to be sensitive to the action of proteinase K, suggesting that it is a protein. It is present in normal cells in high amounts, it is stable on storage and can still be detected in the injected cells 8 h after injection. The microinjection assay described in this paper provides a useful tool for the purification of the XP‐A (and possibly other) factor(s) involved in DNA repair.