IMMUNOLOGICAL PROBING OF INDUCTION AND REPAIR OF 8-METHOXYPSORALEN PHOTOADDUCTS IN DNA FROM FANCONI ANEMIA AND NORMAL HUMAN FIBROBLASTS - QUANTITATIVE-ANALYSIS BY ELECTRON-MICROSCOPY
S. Rousset et al., IMMUNOLOGICAL PROBING OF INDUCTION AND REPAIR OF 8-METHOXYPSORALEN PHOTOADDUCTS IN DNA FROM FANCONI ANEMIA AND NORMAL HUMAN FIBROBLASTS - QUANTITATIVE-ANALYSIS BY ELECTRON-MICROSCOPY, Journal of photochemistry and photobiology.B, Biology, 18(1), 1993, pp. 27-34
A direct method of immuno-electron microscopy has been employed to sim
ultaneously determine 8-methoxypsoralen (8-MOP) photoinduced monoadduc
ts (MA) and interstrand cross-links (CL), their relative localization
along the DNA molecule, and their removal. It has been applied to DNA
from cultures of Fanconi anemia (FA) fibroblasts (complementation grou
ps A and D), and of normal human fibroblasts, following treatment by 8
-MOP and 365 nm radiation. The immuno-reaction with monoclonal antibod
y 8G1 was performed on DNA extracted from the cells just after photore
action, or after a 24 h repair period, and then denatured. Furan-side
MA and also a significant proportion of pyrone-side MA were very effic
iently immuno-detected. Only 1-2% CL were IgG-labeled. This is why CL
were directly visualized and quantified on denatured DNA from the same
cellular samples as used for immuno-detection. Results demonstrate th
at FA group A cells are not only impaired in the incision of CL, but a
lso of MA. The response of FA group D cells is intermediate between no
rmal and FA group A cells.