Expression strategies of the yeast retrotransposon Ty: a short sequence directs ribosomal frameshifting.
The Ty element of yeast is a member of a class of eukaryotic transposons which bear a striking resemblance to retroviral proviruses in their structure and expression strategies (1,2). A direct comparison can be drawn between the production of a fusion protein encoded by Ty, resulting from a frameshift event which fuses two out-of-phase open reading frames TYA and TYB, and the production of Pr180gag-pol in a retrovirus such as Rous Sarcoma Virus (RSV) (3,4). We present data which shows, definitively, that RNA splicing is not responsible for the frameshift in Ty. By in vitro mutation of a class I element, Ty1-15, we demonstrate that 31 nucleotides contained within the region where the TYA and TYB open reading frames overlap direct the frameshift. Within this short sequence there is a region of homology with a class II element which we show is also able to frameshift.
D001483:Base Sequence; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D004271:DNA, Fungal / Q000235:genetics; D005786:Gene Expression Regulation; D014176:Protein Biosynthesis; D012326:RNA Splicing; D012270:Ribosomes / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D004251:DNA Transposable Elements; D004271:DNA, Fungal