Extending the length of βG-Δi mRNA promotes its nuclear export. For each of the fusion constructs in Figures 1A, 2A, and 4A, the length of insertion added upstream of the βG-Δi ORF mRNA is plotted against the percentage of cytoplasmic to total mRNA. Consistent with the idea that the 3′ terminal portion of the βG-Δi mRNA contains a nuclear retention element, constructs that contain one copy of this region are in black and generally follow one trend, while constructs that contain two copies of this region are in gray, are much more nuclear and follow a different trend. Note that the data were obtained from different experiments that were not all done in parallel but all performed in U2OS cells.
