The Drosophila gene twister, an orthologue of the yeast helicase SKI2, is differentially expressed during development

We have identified and characterized a Drosophila orthologue of SK12, which, in Saccharomyces cerevisiae. is one of the key components in the cytoplasmic 3 ' -5 ' decay of mRNA. The Drosophila orthologue (twister, tst), is expressed as two transcripts which differ in the lengths of their 3 ' -UTRs, with the smaller transcript being particularly abundant in 0-2 h embryos and the larger transcript reaching its highest levels in 6-8 h embryos. TST protein is expressed in two forms which are differentially expressed in adult tissues and throughout development. Differential expression of TST may modulate activity of the mRNA turnover pathway and could have a major impact on the expression of target RNAs.