Figure 5.

(A) Sequences of selected RRE binders. In one screen, a total of 35 GFP-positive clones were identified and six different sequences were found (clones 1–6). In a second screen, 12 new sequences were found after four rounds of sorting using a slightly lower window. Many additional clones were obtained from the second screen but were not sequenced. The position corresponding to Asn-40 of Rev is indicated by arrows. (B) Activities of Tat fusion proteins on an HIV LTR RRE IIB-CAT reporter. The fusion plasmids shown (1, 5, and 25 ng) were cotransfected with the reporter (50 ng) and CAT activities were measured after 48 hr. Fold activation was calculated as the ratio of activities with and without the Tat-expression plasmids.