RNA metabolism in primary cultures of Xenopus laevis kidney cells

Inhibitor of ribosomal RNA synthesis in Xenopus laevis embryos. VII. Inhibition of 40S pre-rRNA synthesis in Xenopus neurula cells.

“…1A). This profile is very similar to that of primary cultured Xenopus kidney cells pulse-labeled in the logarithmic phase of growth (7). When neurula cells were treated with the blastula PCA-extract, the accumulations of 40S pre-rRNA, 28S and 18S mature rRNA were greatly reduced, the respective inhibitions being about 90, 81 and 87 % (Fig.…”

“…The RNA was electrophoresed on 0.5 % agarose-2.0 % polyacrylamide gels. Identification of the 40S rRNA precursor was made as described previously by Misumi et al (7). Tubercidin was a gift from Dr. M. Saneyoshi, Hokkaido University.…”

“…1 and 2 reveals that the effect of blastula PCA-extract differed markedly from that of tubercidin; the former inhibited the labeling of 40S pre-rRNA, whereas the latter enhanced the accumulation of 40S pre-rRNA. For Xenopus, 40S pre-rRNA is accepted to be the primary transcript (2,4,7,8,16) although there have been some reports suggesting the existence of a larger precursor (1,11). Thus, there is the implication that the PCA-extract suppresses formation of the primary transcript.…”