Different genetic alterations underlie dual hypersensitivity of CHO mutant UV-1 to DNA methylating and cross-linking agents

Cynthia A. Hoy, Larry H. Thompson, Edmund P. Salazar, Sheri A. Stewart

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

CHO mutant UV-1, isolated on the basis of hypersensitivity to UV radiation (254 nm), was further characterized with respect to sensitivity to classes of DNA damaging agents in a differential cytotoxicity (DC) assay. Compared to its parental strain, Gly-A, UV-1 was dramatically (10-to 100-fold) hypersensitive to both DNA methylating and cross-linking agents. In addition, UV-1 was moderately (two- to fourfold) hypersensitive to several other classes of mutagens. DNA isolated from UV-1 or Gly- A after exposure to14C-labeled methylnitrosourea (MNU) contained similar amounts of label, thus ruling out differences in uptake or binding. Three phenotypic revertants of UV-1 were resistant to N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) and other methylating agents but retained hypersensitivity to cross-linking agents. Moreover, fusion of UV-1 with two different UV-sensitive CHO mutants also having hypersensitivity to cross-link and methylation damage produced hybrids resistant to mitomycin C (MMC) but not to methyl methane sulfonate (MMS). Since the methylation and cross-link sensitivities were uncoupled in both genetic tests, the complex phenotype of UV-1 is likely due to more than one genetic alteration.

Original languageEnglish (US)
Pages (from-to)523-532
Number of pages10
JournalSomatic Cell and Molecular Genetics
Volume11
Issue number6
DOIs
StatePublished - Nov 1985
Externally publishedYes

ASJC Scopus subject areas

  • Genetics
  • Cell Biology

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