Yeast is unable to excise foreign intervening sequences from hybrid gene transcripts.

To investigate whether transcripts from foreign split genes are correctly processed in yeast cells we have constructed two hybrid genes by inserting into the split yeast actin gene an intron-containing fragment from either the Acanthamoeba actin I gene or the duck alpha D-globin gene. The hybrid genes were inserted into the autonomously replicating yeast plasmid YRp7, which was then used to transform yeast cells. It was found that the yeast but not the foreign intervening sequences were excised from the chimeric transcripts. This indicates that the recognition of intervening sequences or the splicing mechanism of RNA polymerase II transcripts is not universal.