Figure 3

Detection of the K222 provirus in the genome of human cell lines by slot blot analysis. The DNA of human cell lines that were found to have or lack the 5′ end of K111 by PCR, and presumably contain the truncated K222 provirus, were screened for K111 and K222 by slot blot analyses. (A) Generation of K111 and K222-specific biotinylated probes. Probes were generated by PCR incorporation of biotin-labeled dCTP. The K111 probe is 422 bp long and spans the CER:D22Z3 flanking sequence and the beginning of the LTR of K111. The K222 probe is 464 bp long and covers the pCER:D22Z8 flanking sequence and pro gene of K222. (B) DNA from the B-cell lines BJAB (having the 5′ end of K111) and IRA (lacking the 5′ end) as observed by PCR, were screened for K111 and K222 virus by slot blotting. DNA was cross-linked to PVDF membranes and screened for K111 and K222 using biotinylated probes. The probes were detected by chemiluminescence with HRP-conjugated streptavidin. The K111 probe, which targets the 5′ end of genomic K111, reacted with the DNA of BJAB cells but not IRA cells, confirming the lack of the 5′ end of the viral genome in IRA cells. The K222 probe reacted with the DNA of both BJAB and IRA cells, confirming that both cell lines have provirus K222, which is truncated at the 5′ end. Mouse DNA served as a negative control, and plasmids containing either K111 or K222 genomes were used as positive controls. The K111 probe did not react with the K222 plasmid and vice versa.