Synthesis of transfer RNA during the synchronous nuclear division cycle in Physarum polycephalum

1. The synthesis of tRNA during the synchronous nuclear division cycle in plasmodia of Physarum polycephalum has been investigated using an isotope dilution procedure and compared to the pattern of synthesis of rRNA. 2. The synthesis of both tRNA stops during mitosis. As the genes for the two types of RNA are not linked, this finding suggests that cessation of synthesis during nuclear division is a common characteristic of all types of transcription, supporting earlier work using pulse labelling and autoradiography to investigate the same problem.