Abstract
The incorporation pattern of 3H-uridine into various RNA species was examined at the lag, logarithmic and stationary phases in primary cultures of Xenopus laevis kidney cells. The relative amount of labeling of 40S ribosomal RNA precursor was strikingly high in stationary phase cells. It was suggested that in addition to the transcription rate of ribosomal RNA genes, the processing rate of the ribosomal RNA precursor may be reduced when cellular proliferation becomes inactive at the stationary phase.
