Exon composition of clones derived from DS rev and tat RNAs expressed by three subtype C isolates*.

Exons 1, 2, 3, 4c, and 4 are named as in previous studies [1], [2]. Exons 4f and 4g designate those using newly identified 3'ss A4f and A4g, respectively, and exon 2a designates that using 3'ss A1 and newly identified 5'ss D2a (see main text). All transcripts are assumed to include exon 7 through splicing from 5'ss D4 to 3'ss A7. However this splice junction was not sequenced, since the antisense PCR primer anneals upstream of D4. nef RNAs were not amplified because the antisense PCR primer recognizes a sequence upstream of 3'ss A5.