Complementation of defective translesion synthesis and UV light sensitivity in xeroderma pigmentosum variant cells by human and mouse DNA polymerase eta.
Defects in the human gene XPV result in the variant form of the genetic disease xeroderma pigmentosum (XP-V). XPV encodes DNA polymerase eta, a novel DNA polymerase that belongs to the UmuC/DinB/Rad30 superfamily. This polymerase catalyzes the efficient and accurate translesion synthesis of DNA past cis-syn cyclobutane di-thymine lesions. In this report we present the cDNA sequence and expression profiles of the mouse XPV gene and demonstrate its ability to complement defective DNA synthesis in XP-V cells. The mouse XPV protein shares 80.3% amino acid identity and 86.9% similarity with the human XPV protein. The recombinant mouse XPV protein corrected the inability of XP-V cell extracts to carry out DNA replication, by bypassing thymine dimers on template DNA. Transfection of the mouse or human XPV cDNA into human XP-V cells corrected UV sensitivity. Northern blot analysis revealed that the mouse XPV gene is expressed ubiquitously, but at a higher level in testis, liver, skin and thymus compared to other tissues. Although the mouse XPV gene was not induced by UV irradiation, its expression was elevated approximately 4-fold during cell proliferation. These results suggest that DNA polymerase eta plays a role in DNA replication, though the enzyme is not essential for viability.
Yamada
A
A
Institute for Molecular and Cellular Biology, Osaka University and CREST, Japan Science and Technology Corporation, Yamada-oka, Japan,
Masutani
C
C
Iwai
S
S
Hanaoka
F
F
D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division; D002460:Cell Line; D002470:Cell Survival / Q000528:radiation effects; D003001:Cloning, Molecular; D004261:DNA Replication / Q000235:genetics; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000528:radiation effects; D005816:Genetic Complementation Test; D014644:Genetic Variation / Q000235:genetics; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D011740:Pyrimidine Dimers / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011836:Radiation Tolerance / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection; D014466:Ultraviolet Rays; D014983:Xeroderma Pigmentosum / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000094769:DNA Polymerase iota; D000099270:Y-Family DNA Polymerases
D004259:DNA-Directed DNA Polymerase; D011740:Pyrimidine Dimers; D012333:RNA, Messenger; D000094769:DNA Polymerase iota; C112338:Rad30 protein; D000099270:Y-Family DNA Polymerases