Splicing of RPL30 and SPR28 pre-mRNA is responsive to environmental signals. We resolved RT-PCR products spanning the introns of either RPL30 or SPR28 by gel electrophoresis. We observe the same effects in multiple experiments, and in multiple strain backgrounds (data not shown). Owing to inherent biases of PCR, volume quantitations of lane plots (right) do not necessarily reflect absolute RNA levels, but do reflect changes in proportion. (A) RNA for RPL30 analysis was extracted from cells grown at either 16°C or 37°C. RT-PCR products were identified by sequencing and correspond to the RNAs diagrammed to the left. Labeled sequences correspond to 5′-splice sites, with noncanonical nucleotides underscored. (Boxes) Exons; (lines) introns; (gray lines) the portion of intron retained when the alternative 5′-splice site is used. (B) RNA for SPR28 analysis was extracted from cells grown in the presence or absence of α-factor. The four products correspond in size to the RNAs diagrammed on the left. Identities of all forms, except for the shorter partially spliced form, were confirmed by sequencing.
