A human and a plant intron-containing tRNATyr gene are both transcribed in a HeLa cell extract but spliced along different pathways.

摘要: tRNA splicing enzymes had been identified in mammalian and plant cells long before homologous intron-containing genes were detected. The tRNATyr gene presented here is the first intron-containing, human for which transcription pre-tRNA maturation has studied a system. This disrupted by 20-bp intron encodes one of two major tRNAsTyr have purified sequenced. A recently isolated from Nicotiana also contains an codes functional, cytoplasmic tRNATyr. Both are efficiently transcribed HeLa cell nuclear extract. Each them produces independent primary transcripts because initiation termination sites, respectively. precursors proceeds along different pathways. intervening sequence pre-tRNATyr excised first, followed ligation halves flanks, as shown all order steps reversed pre-tRNATyr: processing flanking sequences precedes excision. pathway corresponds to that observed vivo biosynthesis Xenopus oocytes yeast.