LOCALIZATION OF THE XANTHINE GUANINE PHOSPHORIBOSYL TRANSFERASE GENE (GPT) OF ESCHERICHIA-COLI IN AS52 METAPHASE CELLS BY FLUORESCENCE IN-SITU HYBRIDIZATION

The purpose of this study was to localize the xanthine guanine phosphoribosyl transferase gene (gpt) to a specific chromosome to investigate its proposed autosomal location in the AS52 cell line. AS52 cells are hgprt-deficient Chinese hamster ovary (CHO) cells which carry a single functional copy of the E. coli gpt gene. Fluorescence in situ hybridization (FISH) and digoxigenin-labeled probes, as smell as 673 bp, were used in an attempt to localize the 456 bp gpt gene to a specific chromosome. Chi-square analysis of 13 metaphases showed significant labeling on autosomal chromosomes 6 or 7, which are indistinguishable without further bonding analysis. Furthermore, a majority of the signals were on the q arm, proximal to the centromere. The data collected supports incorporation of the gpt gene into an acrocentric autosome of the AS52 cell line. (C) 1994 Wiley-Liss, Inc.