Evidence for the packaging of multiple copies of Tfl mRNA into particles and the trans priming of reverse transcription

Long terminal repeat (LTR)-containing retrotransposons and retroviruses are close relatives that possess similar mechanisms of reverse transcription. The particles of retroviruses package hco copies of viral mRNA that both fu nction as templates for the reverse transcription of the element. We studie d the LTR-retrotransposon Tf1 of Schizosaccharomyces pombe to test whether multiple copies of transposon mRNA participate In the production of cDNA. U sing the unique self-priming property of Tf1, we obtained evidence that mul tiple copies of Tf1 mRNA mere packaged into virus-like particles. By coexpr essing two distinct versions of Tf1, we found that the bulk of reverse tran scription that was initiated on one mRNA template was subsequently transfer red to others. In addition, the first 11 nucleotides of one mRNA were able to prime, in trans, the reverse transcription of another mRNA.