TABLE 1.

Effects of postinfection AZT treatment^a on the mutant frequency in recovered HIV-1 proviruses

AZT concn (μM)	Relative amt of virus production	No. of independent mutants/total no. of bacterial colonies	Mutant frequencyb (no. of mutations/cycle)	Relative mutation frequency
0.0	1	8/1,879	0.004	1
		12/2,207	0.005
		15/2,341	0.006
0.1	0.8	14/2,452	0.006	1.4
		24/2,978	0.008
		22/2,720	0.008
0.2	0.4	34/1,985	0.017	3.8
		44/2,341	0.019
		49/2,253	0.022
0.4	0.2	63/1,726	0.037	7.6
		75/2,068	0.036
		79/1,918	0.041

^aReferred to as posttreatment. Target cells were treated with the indicated concentration of AZT for 2 h prior to cocultivation, and AZT was continued for 24 h after cocultivation with mitomycin C-treated virus-producing cells. Proviral DNA from target cells was then purified and screened for mutations in E. coli. 

^bStandard deviations are 0.001, 0.002, 0.004, and 0.004 mutant/cycle for mutant frequencies at AZT concentrations of 0, 0.1, 0.2, and 0.4 μM, respectively.