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Role of poly(ADP–ribose) polymerase (PARP) in DNA repair in sulfur mustard‐exposed normal human epidermal keratinocytes (NHEK) † ‡
Author(s) -
Bhat K. R.,
Benton B. J.,
Rosenthal D. S.,
Smulson M. E.,
Ray R.
Publication year - 2000
Publication title -
journal of applied toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.784
H-Index - 87
eISSN - 1099-1263
pISSN - 0260-437X
DOI - 10.1002/1099-1263(200012)20:1+<::aid-jat695>3.0.co;2-g
Subject(s) - dna ligase , dna repair , poly adp ribose polymerase , microbiology and biotechnology , dna damage , biology , dna , polymerase , chemistry , biochemistry
We previously reported that, in normal human epidermal keratinocytes (NHEK) cultures exposed to the alkylating compound sulfur mustard (bis‐(2‐chloroethyl) sulfide, HD, 0.3–1 mM), there is a rapid (≤1 h) activation (100% above unexposed control) of the DNA repair enzyme DNA ligase I (130 kD) followed by a first‐order decay (1–5 h). The DNA ligase activation is accompanied by a time‐dependent (0.5–4 h) and significant DNA repair. Inhibition of another putative DNA repair enzyme, poly(ADP–ribose) polymerase (PARP), by using 3‐amino benzamide does not affect DNA ligase activation following HD exposure, but increases the half‐life of the activated enzyme threefold. To examine the role of PARP in HD‐induced DNA ligase activation and subsequent DNA repair, we conducted studies using cultured keratinocytes in which the level of PARP had been selectively lowered (≥85%) by the use of induced expression of antisense RNA. In these cells, there was no stimulation of DNA ligase up to 3 h, and a small stimulation (ca. 30% above unexposed control at 5–6 h after HD exposure. A time‐course (0.5–6 h) study of DNA repair in HD‐exposed PARP‐deficient keratinocytes revealed a much slower rate of repair compared with HD‐exposed NHEK. The results suggest an active role of PARP in DNA ligase activation and DNA repair in mammalian cells, and also indicate that modulation of PARP‐mediated mechanisms may provide a useful approach in preventing HD toxicity. Published in 2000 by John Wiley & Sons, Ltd.