Spatial consequences of defective processing of specific yeast mRNAs revealed by fluorescent in situ hybridization.

This work introduces the first use of fluorescent in situ hybridization (FISH) to detect the distribution of specific transcripts in Saccharomyces cerevisiae. We have applied this technique to analysis of reporter transcripts from a single, integrated copy, or multicopy plasmids. We have evaluated the effect of splice site deletions or the presence or absence of a terminator/cleavage site and demonstrated that both splicing and polyadenylation affect the export of these transcripts from the nucleus to the cytoplasm. Moreover, we show that the exported pre-mRNAs are substrates for nonsense codon-mediated decay through the UPF1 pathway. The work presented here demonstrates that the spatial distribution of transcripts will also be an important component of yeast RNA metabolism.