Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.3.1.51 (HDR)
 605 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This study evaluates seven alternative assays carried out on the main ingredients in cosmetics to determine which battery is the best set and what is the best predictor of the maximal Draize rabbit eye irritation scores (MDESs). The assays consisted of the maximal primary Draize rabbit skin irritation scores (MDSSs), a cytotoxicity test on neutral red uptake using Chinese hamster lung cells (NR-EC(50)), a cytotoxicity test on MTT using normal skin fibroblasts (MTT-EC(50)), the hen's egg test-chorioallantoic membrane test using fertile chicken eggs (HET-CAM), a haemolysis test using red blood cells from Wistar rats (HC(50)), a protein denaturation test using haemoglobin from bovine (HDR), and pH. We tested 10% solutions of 24 tested chemicals, that is, 20 surfactants, three solvents and formaldehyde, to select from the assays a best set for prediction (x) and to obtain the best predictor [f(x)] based on the prediction sum of squares criterion. The selected set consisted of NR-EC(50) and HDR, and the resultant best predictor was f(x) = 74.0 - 29.52 log(NR-EC(50)) + 0.87 HDR. This predictor achieved a high score of 89.6% of the contribution ratio. For two of the 24 test chemicals, an inconsistency occurred in the criticality of corneal damage between the observed and predicted Draize eye scores, although this is not considered to affect significantly the overall results.
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PMID:Evaluation of seven alternative assays on the main ingredients in cosmetics as predictors of Draize eye irritation scores. 2065 95

FANCD2 is required for the repair of DNA damage by the FA (Fanconi anemia) pathway, and, consequently, FANCD2-deficient cells are sensitive to compounds such as cisplatin and formaldehyde that induce DNA:DNA and DNA:protein crosslinks, respectively. The DNA2 helicase/nuclease is required for RNA/DNA flap removal from Okazaki fragments during DNA replication and for the resection of DSBs (double-strand breaks) during HDR (homology-directed repair) of replication stress-induced damage. A knockdown of DNA2 renders normal cells as sensitive to cisplatin (in the absence of EXO1) and to formaldehyde (even in the presence of EXO1) as FANCD2(-/-) cells. Surprisingly, however, the depletion of DNA2 in FANCD2-deficient cells rescues the sensitivity of FANCD2(-/-) cells to cisplatin and formaldehyde. We previously showed that the resection activity of DNA2 acts downstream of FANCD2 to insure HDR of the DSBs arising when replication forks encounter ICL (interstrand crosslink) damage. The suppression of FANCD2(-/-) by DNA2 knockdowns suggests that DNA2 and FANCD2 also have antagonistic roles: in the absence of FANCD2, DNA2 somehow corrupts repair. To demonstrate that DNA2 is deleterious to crosslink repair, we used psoralen-induced ICL damage to trigger the repair of a site-specific crosslink in a GFP reporter and observed that "over-resection" can account for reduced repair. Our work demonstrates that excessive resection can lead to genome instability and shows that strict regulatory processes have evolved to inhibit resection nucleases. The suppression of FANCD2(-/-) phenotypes by DNA2 depletion may have implications for FA therapies and for the use of ICL-inducing agents in chemotherapy.
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PMID:Preventing over-resection by DNA2 helicase/nuclease suppresses repair defects in Fanconi anemia cells. 2462 99