Tandem UAA repeats at the 3'-end of the transcript are essential for the precise initiation of reverse transcription of the I factor in Drosophila melanogaster.

摘要: Non-long terminal repeat retrotransposons, widespread among eukaryotic genomes, transpose by reverse transcription of an RNA intermediate. Some them, like L1 in the human, terminate at 3′-end with a poly(dA) stretch whereas others, I factor Drosophila melanogaster, have instead short sequence repeated tandem. This suggests different requirements for initiation transcription. Here, we used circularization/reverse transcription-PCR technique to analyze 5′- and 3′-ends full-length transcripts produced time active retrotransposition. These are capped polyadenylated similar conventional messenger RNAs. We analyzed transposed copies elements mutated 3′-ends. Transcripts devoid tandem UAA repeats, although capable building components retrotransposition machinery, inefficiently as intermediates. Such produce rare new integrated issued from inaccurate near element. The repeats required efficient precise strong specificity transcriptase its own transcript has implications impact on host genome.