The odyssey of a regulated transcript.

The transcript of the Saccharomyces cerevisiae gene, RPL30, is subject to regulated splicing and regulated translation, due to a structure that interacts with its own product, ribosomal protein L30. We have followed the fate of the regulated RPL30 transcripts in vivo. Initially, these transcripts abortively enter the splicing pathway, forming an unusually stable association with U1 snRNP. A large proportion of the unspliced molecules, however, are found in the cytoplasm. Most of these are still bound by L30, as only a small fraction are engaged in translation. Eventually, the unspliced RPL30 transcripts escape the grasp of L30, associate with ribosomes, and fall prey to nonsense mediated decay.