(A) Simulations predict that slowing the nuclear export rate shifts the nuclear-to-cytoplasmic noise ratio by affecting nuclear noise.
(B–C) smFISH analysis of HIV LTR–expressed mRNA in isoclonal cells treated with the nuclear-export inhibitor leptomycin B (green). Nuclear mean and noise increase whereas cytoplasmic mean or noise remain unchanged (grey).
(D) Comparison of nuclear versus cytoplasmic mRNA noise by smFISH analysis before and after leptomycin B treatment. All isoclonal populations remain in the amplification regime.
(E) Protein (d2GFP) noise of the same isoclones measured by flow cytometry before and after 5 hours of leptomycin B treatment. As predicted, no change in noise is observed. Inset: cytoplasmic mRNA noise from (C) for comparison. All data points represent means of two biological replicates, and error bars represent SEM.