Figure 6

The strength of the 3'ss competes with Rev responsiveness. (A) Northern blot analysis (cf. Fig. 2) from HeLa-T4⁺ cells transfected with constructs containing the HIV-1 3'ss in absence of their authentic 3' exon sequences. The particular 3'ss and the co-transfection of a rev expressing plasmid (SVcrev) are given above the lanes. The 3'ss A7^- and A7⁺ were used as reference constructs for a nonfunctional and an efficient 3'ss. All lanes were derived from the same Northern blot. (B) Northern blot analysis from cells transfected with 3'ss in presence of their authentic 3' exon sequences (ex). All lanes were derived from the same blot. (C) Mean values of the relative amounts of spliced transcripts in absence and presence of the 3' exon sequences from three independent experiments, normalized to transcription efficiency (hGH, cf. Fig. 2). The amount of spliced transcripts derived from the construct containing the improved A7⁺ was defined as 100% (not shown).