FIG 2.
Influence of virion-incorporated mA3 on specific infectivity and virion RT activity. (A) Virion p30 was determined from immunoblots of gels of virion proteins contained culture supernatant from 3T3/CasFrKP and 3T3mA3/CasFrKP cells. Ratios of the intensities of the bands determined by ImageJ densitometry are shown below the sets of bands. Two different levels of each sample were loaded, resulting in sets of bands with nearly identical ratios of intensity. The average of the ratios was used to normalize the infectivity and RT activity determinations. (B) The infectivity of virions released from cells during an 8-h interval was determined by the FIA and normalized to the levels of p30 present in the samples. The determinations are expressed as a percentage of the mean specific infectivity exhibited by virions released from cells not expressing mA3 (3T3/CasFrKP). Error bars represent the standard errors of 3 to 6 determinations. The P value determined by Student's unpaired t test is indicated. P values of <0.05 were considered significant. (C). The RT activities of virions released from cells during an 8-h interval were determined and normalized to the levels of p30 present in the samples. RT activity was determined for virions contained in 2.5 ml of supernatant media of the samples assayed for infectivity and p30. The determinations are expressed as a percentage of the mean specific infectivity exhibited by virions released from cells not expressing mA3 (3T3/CasFrKP). Error bars represent the standard errors of 3 to 6 determinations. The P value determined by Student's unpaired t test is indicated. P values of <0.05 were considered significant.