A, schematic representation of the HPV-16 subgenomic plasmids pT1sd and pT1sde (29) as well as the HPV-16 subgenomic plasmid containing the HIV-1 exon 5 sequence, including the GAR sequence (25, 26), pT1–5/GAR. The L1 and L1i mRNAs produced from these plasmids are indicated. Arrows indicate PCR oligonucleotides 757s and L1AM used for RT-PCR. B, the HIV-1 sequence inserted in pT1sd is shown with the GAR sequence indicated in bold. C, RT-PCR, with oligonucleotides 757s and L1AM, on RNA extracted from HeLa cells transfected with pT1sd, pT1sde, or pT1–5/GAR in the absence or presence of CMV promoter-driven plasmid expressing SRp55. Bands representing L1 or L1i mRNAs are indicated. M represents the molecular weight marker. D, RT-PCR on RNA extracted from HeLa cells transfected with pT1–5/GAR in the absence or presence of various concentrations of SRp55 plasmid. M represents the molecular weight marker.