Association of herpes simplex thymidine kinase gene with chromosome No. 18 in transformed human cells.

The herpes simplex virus type-2 (HSV-2)-transformed human cell line HB-2-3 was fused with thymidine kinase (TK)-deficient mouse cells [LM(TK-)], and 12 independent hybrids were isolated with the use of the HAT (hypoxanthine, amethopterin, and thymidine)-ouabain selection system. Discontinuous polyacrylamide gel electrophoresis studies demonstrated that the HSV-2-specific TK was the selected enzyme in the hybrids. Isoenzyme analysis and karyotyping were used in the analysis of the hybrids for the presence of human chromosomes. All 12 hybrids contained human chromosome No. 18 and the enzyme peptidase A, which is encoded by a gene on this chromosome. Hybrids were exposed to bromodeoxyuridine (BrdUrd) as a means of selection for cells that had lost HSV-2 TK activity. Isoenzyme and karyotyping data obtained from 33 BrdUrd-resistant sublines were consistent with the hypothesis that the HSV-2 TK gene is associated with chromosome No. 18 in the HB-2-3 cell line.