In the transposon copia-related retrovirus-like particles of Drosophila, a 39-nucleotide-long fragment from the 5′-region of Drosophila initiator methionine tRNA (tRNAi Met) is used as the primer for copia minusstrand reverse transcription. This primer tRNAi Met fragment is thought to be produced by cleavage within the mature tRNAi Met sequence. We call this cleavage hyperprocessing. We have previously reported that catalytic RNA of RNase P from Escherichia coli (MlRNA) cleaves the synthetic tRNAi Met precursor in vitro at several sites within the mature tRNA sequence. Based on this result, we proposed a model for formation of the primer tRNA fragment involving RNase P. Here we show that natural tRNAi Met prepared from DrosophUa adult flies can be cleaved by MIRNA. Using mutant tRNAi Met substrates, we also show that these cleavages are dependent on the occurrence of an altered conformation of the tRNA substrate. This is evidence that a tRNA can exist in aqueous solution at least in part in an altered conformation.
|ジャーナル||Journal of Biological Chemistry|
|出版ステータス||Published - 1992 6月 15|
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