Cerebellar tRNA methyltransferases: A development study

Developmental patterns of homologous and heterologous tRNA methylation by cerebellar tRNA methyltransferases are described. The study revealed that: (a) homologous tRNA methylation results in the predominant formation of N²-methyl-guanine and 1-methyladenine; (b) tRNA methyltransferases of bulk-isolated Purkinje and granule cells methylateE. coli tRNA^glu₂ in vitro in a characteristic manner, and (c) the methylation of 8-day-old cerebellar, cortical and hepatic tRNA in vivo yields tRNAs containing different proportions of methylated bases. The findings suggest that the presumably cell-specific populations of cerebellar tRNA methyltransferases continue to alter their substrate recognition characteristics up to and beyond the first month of post-natal life.