Order and intracellular location of the events involved in the maturation of a spliced tRNA

Abstract

Microinjected frog oocytes were used to analyse the RNA processing steps which lead to the appearance of a mature cytoplasmic tRNA^tyr molecule. The results show that removal of the intervening sequence from within a yeast tRNA^tyr precursor, excision of extra 3′ and 5′ nucleotides, addition of a 3′-terminal CCA and modification of at least seven ribonucleotides all occur in the nucleus before the tRNA^tyr is transported to the cytoplasm. Moreover, we find that the ribonucleotide modifications occur in a strict order which precisely correlates with the size alterations of the tRNA^tyr precursor.