Avian sarcoma virus transformed hamster cells resistant to bromodeoxyuridine and deficient in thymidine kinase activity

Abstract

SummaryHamster cells transformed with the Schmidt-l%uppin strain of avian sarcoma virus were selected for resistance to 5-bromodeoxyuridine (BUDI%). The resistant cell lines Ha(SR)BU-25 and Ha(SR)BU-100, proliferated in the presence of 25 and 100 ~g/ml BUDR, respectively. The resistant cells were deficient in thymidine kinase activity. They did not grow in HATG medium and did not incorporate labelled thymidine into DNA.Several single-cell clones were isolated in medium containing i00 ~g/ml BUDR from Ha(St~)BU-100 cells. These isolated cell clones differed in morphology and modal number of chromosomes from each other. None of the clones incorporated thymidine into DNA.The BUDR resistant cells were tested for their tumorigenicity in young hamsters. The number of cells needed for induction of tumor growth was higher with the BUDR resistant cells than with original clone of Ha(SR) cells.All clones of thymidine kinase deficient cells were tested for the presence of the virus genome by fusion with chicken embryo ceils. All clones of Ha(SR)BU-100 cells contained the virus genom% and infectious virus could be rescued from these cells.Therefore, the genome of avian sarcoma virus can persist in virogenic hamster cells growing in the presence of 5-bromodeo~yuridine. These virogenic cells deficient in thymidine kinase activity are useful for preparation of cell hybrids.

Role of 3′‐end of viral genome in tumor heteroinduction by the avian sarcoma virus

“…Wt SR-D virus was a clone of the virus rescued from hamster cells transformed with Schmidt-Ruppin strain of RSV (Altaner et al, 1973).…”

“…Chicken embryo fibroblasts C/E were prepared from chicken helper factor free (Chf) embryos. Wt SR-D virus was a clone of the virus rescued from hamster cells transformed with Schmidt-Ruppin strain of RSV (Altaner et al, 1973).…”