Novel use of a selectable fusion gene as an 'in-out' marker for studying genetic loss in mammalian cells

D.A. Trott, A.P. Cuthbert, C.M. Todd, M. Themis, R.F. Newbold

Research output: Contribution to journalArticlepeer-review


Recent demonstrations of loss of heterozygosity in a wide variety of human cancers suggest that large multilocus genetic deletions (presumably including tumor suppressor genes) constitute a major class of genetic alteration in human carcinogenesis. Here we show that a bifunctional fusion gene (Hytk), suitable for both positive and negative selection, is an effective marker for studying genetic loss in mammalian cells with minimal interference from point-mutational changes. Studies with a transgenic V79 cell line in which a single functional copy of Hytk was stably inserted into the genome in a retroviral vector showed that loss of the marker (and presumably flanking cellular genetic material) could be induced efficiently by ionizing radiation (γ-rays and fast neutrons) but only weakly by the powerful point-mutagen benzo[a]pyrene diol epoxide. In a first application of the system, we provide evidence that radiation-induced loss can occur through an indirect mechanism after a high-frequency event. Collectively, our results suggest that the Hytk marker should be a valuable tool for studying genome position effects on the tolerance of genetic loss in cultured human cells that represent different stages in clonal evolution and tumor progression.
Original languageEnglish
Pages (from-to)213-224
Number of pages12
JournalMolecular Carcinogenesis
Issue number4
Publication statusPublished - 23 Apr 1995


  • 'In-out' selectable marker
  • Gene-deletion assay
  • Genome position effects
  • Loss of heterozygosity
  • animal cell
  • article
  • assay
  • carcinogenesis
  • V79 cell line
  • controlled study
  • gene deletion
  • heterozygosity
  • nonhuman
  • priority journal


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