INCREASED LENGTH OF LONG TERMINAL REPEATS INHIBITS TY1 TRANSPOSITION AND LEADS TO THE FORMATION OF TANDEM MULTIMERS

The Ty1 retrotransposon of Saccharomyces cerevisiae is bounded by long -terminal repeats (LTRs). We have constructed a variety of Ty1 element s in which the LTR length has been increased from the normal length of 334 bp to >2 kb. Although small insertions in the LTR ha ie minimal e ffects on transposition frequency, larger insertions dramatically redu ce it. Nevertheless, elements with long LTRs are incorporated into the genome at a low frequency. Most of these rare insertion events repres ent Ty1 tandem (head to tail) multimers.