A) Rev mobility was measured by FRAP in HeLa cells expressing Rev-GFP. The recovery of the Rev fluorescence in the nucleolar region bleached by laser was measured for 200 sec. Three images were taken before bleaching. B) FRAP analysis shows the effect of NF90ctv and its truncated forms on Rev mobility. HeLa cells were co-transfected with pRev-GFP in the presence of pNF90ctv-mRFP, of pRCN-mRFP, of DRBD1/2-mRFP or of pRG-mRFP and subjected to photobleaching 24 h post-transfection using a 488 nm laser. The average from at least 12 cells is shown. FRAP demonstrates that the FRAP rate of Rev-GFP alone is slower than in the presence of NF90ctv or each of its truncated forms, especially in the presence of RCN. C) The same as A but Rev is in the presence of RRE. D) The same strategies were used as described in B, but in addition, the cells were also transfected with pCMVGag2RRE. The FRAP analysis shows that in the presence of RRE and NF90ctv or each of the truncated forms of NF90ctv, the mobility of Rev was slower during the first 30 sec, but that afterwards Rev its mobility was faster, especially with RCN. As control HeLa cells co-transfected with pRev-GFP and pmRFP were used, but no effect on Rev mobility was detected (results not shown).