DNA repair enzymes in ataxia telangiectasia and Bloom's syndrome fibroblasts

Ionizing radiation-induced mutagenesis

“…Cell free extracts of fibroblasts grown in culture failed to reveal deficiencies for AP endonucleases and urea-DNA glycosylase in the strains tested (Teebor & Duker, 1975;Breimer, 1983). Reports that AT fibroblasts were defective in excision repair of y-ray damaged DNA (Paterson et al, 1976) and that cell extracts of AT cells were deficient in an enzyme which enhanced the priming activity of y-irradiated DNA for DNA polymerase I (Inoue et al, 1977;Edwards et al, 1980) have not been confirmed (van der Schans et al, 1981;Shiloh et al, 1981). The repair proficiency of these fibroblasts generally decrease with increasing passage (Sognier & Hittleman, 1983) making deficiency data difficult to interpret.…”

Human DNA repair systems: An overview

“…The first human repair deficiency disease identified was xeroderma pigmentosum (XP) [Jung and Bantle, 1971;Stich, 1975], a hereditary deficiency in any of several nucleotide excision repair genes. Other human disorders related to defective DNA repair or defective cellular responses to DNA damage include trichothiodystrophy [Rebora and Crovato, 1987], Cockayne syndrome, Fanconi's anemia [Poon et al, 1975], ataxia telangiectasia [Vincent et al, 1975], Bloom's syndrome [Inoue et al, 1977], and hereditary nonpolypopsis colorectal cancer (HNPCC) Bronner et al, 1994]. Clinical disease arising from defects in DNA repair is complex and often severe.…”

Elevated spontaneous mutation rate in Bloom syndrome fibroblasts.

“…Although there have been conflicting reports of cellular sensitivity to UV irradiation or ethylmethanesulfonate exposure (13,14), various measurements of the DNA -repair capacities of Bloom syndrome-cells after DNA damage strongly suggest that the repair functions, as.presently understood, are intact (15)(16)(17)(18)(19)(20)(21)(22)(23). However, evidence provided by Hand and German (24,25) indicates that DNA replication rather than repair may be abnormal in Bloom syndrome.…”