TRANSFER RNA METHYLASES DURING MORPHOGENESIS IN THE CELLULAR SLIME MOLD

The enzymes that methylate tRNA were studied during the life cycle of the colonizing slime mold, Dictyostelium discoideum. Total and base specific tRNA methylase activities were determined in extracts from cells in morphogenetic synchrony. Eight hours after enforced aggregation, the total methylase capacity is reduced by about 40 per cent. The diminution appears to be due to the presence of inhibitors that do not inhibit the base specific enzymes to the same extent. There is a still greater diminution in enzyme activity in extracts of the mature fruiting bodies.