Fig. 2. SMG7 deficiency increases the level of a PTC-containing transcript. (A) Alternative splicing of the At5g62760 gene produces a transcript containing a premature termination codon (+PTC) in the seventh exon (indicated by an asterisk) (Hori and Watanabe, 2005). (B) Detection of the At5g62760 transcripts by RT-PCR and Southern blot analysis. The quantity of the –PTC and +PTC transcripts was determined by quantitative RT-PCR analysis using primers T5-F and T5-R (see Materials and Methods; indicated in A). The relative quantity of the transcripts was determined by the signal ratio of +PTC to –PTC for each sample. The average ratios for +PTC to –PTC for wild-type and smg7-1 samples were 1.05±0.05 and 1.58±0.27, respectively.