title: Cells from long-lived mutant mice exhibit enhanced repair of ultraviolet lesions.
abstract: Fibroblasts isolated from long-lived hypopituitary dwarf mice are resistant to many cell stresses, including ultraviolet (UV) light and methyl methane sulfonate (MMS), which induce cell death by producing DNA damage. Here we report that cells from Snell dwarf mice recover more rapidly than controls from the inhibition of RNA synthesis induced by UV damage. Recovery of messenger RNA (mRNA) synthesis in particular is more rapid in dwarf cells, suggesting enhanced repair of the actively transcribing genes in dwarf-derived cells. At early time points, there was no difference in the repair of cyclobutane pyrimidine dimers (CPD) or 6-4 photoproducts (6-4PP) in the whole genome, nor was there any significant difference in the repair of UV lesions in specific genes. However, at later time points we found that more lesions had been removed from the genome of dwarf-derived cells. We have also found that cells from dwarf mice express higher levels of the nucleotide excision repair proteins XPC and CSA, suggesting a causal link to enhanced DNA repair. Overall, these data suggest a mechanism for the UV resistance of Snell dwarf-derived fibroblasts that could contribute to the delay of aging and neoplasia in these mice.
authors: Cellular and Molecular Biology Graduate Program, University of Michigan Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA.
authors: Adam B
authors: AB
authors: Salmon
authors: Mats
authors: M
authors: Ljungman
authors: Richard A
authors: RA
authors: Miller
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry / Q000235:genetics; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000378:metabolism; D004393:Dwarfism, Pituitary / Q000235:genetics / Q000473:pathology; D004720:Endonucleases / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008815:Mice, Inbred Strains; D008817:Mice, Mutant Strains; D009687:Nuclear Proteins / Q000378:metabolism; D011740:Pyrimidine Dimers / Q000032:analysis / Q000737:chemistry; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism; D014466:Ultraviolet Rays; D000099250:DNA Excision Repair Protein ERCC-5
chemical_list: D004247:DNA; D004268:DNA-Binding Proteins; D004720:Endonucleases; D009687:Nuclear Proteins; D011740:Pyrimidine Dimers; D012333:RNA, Messenger; D014157:Transcription Factors; D000099250:DNA Excision Repair Protein ERCC-5; C095888:xeroderma pigmentosum group F protein