FIG. 8.

Inhibition of U6 snRNA interactions with m⁷GpppG-capped Ad1WW pre-mRNA by the m⁷GpppG cap analogue but not the ApppG cap analogue. HeLa nuclear extract was preincubated with the m⁷GpppG or the ApppG cap analogue for 15 min prior to the addition of the pre-mRNA. The final concentrations of m⁷GpppG and ApppG were 0, 5, 10, 20, 50, and 100 μM, as marked above the gel. The cross-linked RNA was resolved on a 5% polyacrylamide gel. The bar charts aligned below the image show the relative intensities of specific products and the pre-mRNA (expressed as percentages) for each lane. The products measured are U1 cross-linked to the upstream 5′ splice site (the major site of splicing), U6 cross-linked, and the upstream (u/s) mRNA, as indicated by the y axis labels.