Changes in the patterns of RNA synthesis in early embryogenesis of Xenopus laevis

Koichiro Shiokawa, Yuko Misumi, Kosuke Tashiro, Norihiko Nakakura, K. Yamana, Mamoru Oh-uchida

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


We analyzed the accumulation of newly-synthesized heterogeneous mRNA-like RNA, 4 S RNA, 5 S RNA, snRNAs and rRNA before and after the midblastula transition (MBT) in Xenopus laevis embryogenesis. Based on the kinetics of the labeling, we concluded that the pattern of RNA synthesis in Xenopus embryogenesis changes following at least three characteristically different phases. The first phase is the pre-MBT stage, which is characterized by the synthesis of heterogeneous mRNA-like RNA, accompanied by the synthesis of small amounts of 4 S RNA, 5 S RNA and snRNAs. The second phase is the MBT stage which is characterized by a large activation (about 50-fold increase on a per cell basis) of 4 S RNA synthesis. The third phase is the post-MBT stage which is characterized by the commencement and increase in rRNA synthesis. We assume that RNA polymerases II, III and I are activated in this order in early Xenopus embryogenesis.

Original languageEnglish
Pages (from-to)17-25
Number of pages9
JournalCell Differentiation and Development
Issue number1
Publication statusPublished - Oct 1989
Externally publishedYes


  • Low-molecular-weight RNA
  • Midblastula transition
  • Preblastula RNA synthesis
  • Xenopus embryonic cell

ASJC Scopus subject areas

  • Developmental Biology


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