FIG. 1.

Detection of the linear form of HIV-1 DNA using LM-PCR. The final product of the reverse transcription reaction is a linear genome with blunt ends. To detect linear products of the reverse transcription reaction, genomic DNA was isolated from infected cells and loaded into a ligation reaction mixture containing a vast molar excess of an asymmetric blunt linker. The ligation of linker onto the end of the genome was detected by PCR with an HIV-1-specific primer and one complementary to the linker. In some experiments, a heminested PCR approach was employed. Production of an HIV-1-specific amplicon was universally T4 ligase dependent.