Figure 4

Dependence of the intracellular Rev protein kinetics on the re-export scale from the nucleus to the cytoplasm. The upper panel shows the model simulations in which the interaction of the Rev protein with the 9 kb and 4 kb RNAs in cytoplasm is excluded. The presented curves were computed for various numbers of the Rev protein molecules exported from the nucleus to the cytoplasm due to the transport of the multimeric complexes <Rev_(i)_9 kb-RNA_nuc> and the <Rev_(i)_4 kb-RNA_nuc> from the nucleus to the cytoplasm, i = 1,...,6. Curve 1 corresponds to the scenario when all the Rev protein molecules in the i-meric oligomer complex are released in the nuclear pore complex so that none of the Rev protein molecules enters the cytoplasm; curves 2,3,4,5,6, and 7 represent the Rev protein kinetics characterized by the export of 1,2,3,4,5 and 6 molecules of the Rev protein to the cytoplasm with the i-meric complex, respectively. The rest of the molecules of the above complexes as well as of the complexes with a lower number of the Rev proteins are released in the nuclear pore complex to remain in the nucleus. The lower panel shows the model simulations corresponding to the scenario in which a complete nuclear export of the Rev molecules to the cytoplasm and the interaction of Rev with the 9 kb and 4 kb RNAs in the cytoplasm take place. The effect of k _dis is shown with curve 1 corresponding to k _dis = 8.4 min^-1, curve 2 to k _dis = 20 min^-1 and curve 3 to k _dis = 50 min^-1. The vertical axis specifies the number of unbound Rev protein molecules in the nucleus.