Figure 6.

Both frame-disrupting and frame-neutral insertions and deletions elicit pre-mRNA upregulation. (A) Schematic diagrams of construct A variants harboring either a 1-nt insertion at codon 114 (+1, construct A^I2+), a 1-nt deletion at codon 146 (−1, construct A^D1+), both the 1-nt insertion and deletions (+1/−1, construct A^I2D1) or a 3-nt insertion (+3, construct A^I3). The location of the downstream PTC generated by the +1 and −1 mutations are shown. (B) RNase protection analysis performed using probe 1 (A) and a Neo probe (Figure 1) on total cellular RNA (10 µg) harvested from HeLa cells transiently transfected with constructs shown. (C, D) Quantification of mature mRNA (C) and pre-mRNA (D) levels from cells analyzed as in (B). Values are the average of three experiments, determined as described in Figure 1. Error bars indicate standard error. (E) Splicing rate as measured by pre-mRNA-to-mRNA ratio, determined as in Figure 5E, using the values in (C) and (D).