Isolation and characterization of human cells resistant to retrovirus infection

Retrovirology

Table 1 Rounds of mutagenesis to generate mutations at diploid loci.

	6-thioguanine resistant (HPRT-) colonies per 10⁷ cells	Diaminopurine resistant (APRT-) colonies per 10⁷ cells
Spontaneous	0	0
Round 1 mutagenesis	NA	0
Round 2 mutagenesis	NA	0
Round 3 mutagenesis	NA	0
Round 4 mutagenesis	NA	0
Round 5 mutagenesis	NA	1
Round 6 mutagenesis	31	10
Round 7 mutagenesis	26	31

NA = not assayed
Appearance of Diaminopurine and 6-thioguanine resistant colonies examined at each round of mutagenesis with ICR-191. Mutagenized HeLa cells were selected in the presence of 6-thioguanine (6-TG) and Diaminopurine (DAP) to isolate APRT (-) and HPRT (-) colonies respectively, which serve as indicators of mutagenesis at diploid loci.

ISSN: 1742-4690