Occurrence of pre-MBT synthesis of caspase-8 mRNA and activation of caspase-8 prior to execution of SAMDC (S-adenosylmethionine decarboxylase)- induced, but not p53-induced, apoptosis in Xenopus late blastulae

Koichiro Shiokawa, Eiji Takayama, Takayasu Higo, Shinsaku Kuroyanagi, Chikara Kaito, Hiroshi Hara, Masayuki Kajitani, Kazuhisa Sekimizu, Takushi Tadakuma, Kin Ichiro Miura, Kazuei Igarashi, Yoshio Yaoita

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Overexpression of S-adenosylmethionine decarboxylase (SAMDC) in Xenopus fertilized eggs activates caspase-9 and executes maternal program of apoptosis shortly after midblastula transition (MBT). We find that overexpression of caspase-8 and p53, like that of SAMDC, induces apoptosis in Xenopus late blastulae. The apoptosis induced by p53 was abolished by injection of mRNA for xdm-2, a negative regulator of p53, and by injection of a peptide inhibitor or a dominant-negative type mutant of caspase-9, but not caspase-8. The apoptosis induced by SAMDC was not abolished by injection of xdm-2 mRNA, but was abolished by injection of a peptide inhibitor or a dominant-negative type mutant mRNA of both caspase-9 and caspase-8. Unlike caspase-9 mRNA, caspase-8 mRNA did not occur as a maternal mRNA rather induced to be expressed during cleavage stage (pre-MBT stage) by overexpression of SAMDC but not p53. Furthermore, while activities to process procaspase-8 and procaspase-9 appeared in SAMDC-overexpressed apoptotic embryos, the activity to process procaspase-8 did not appear in p53-overexpressed apoptotic embryos. We conclude there are at least two pathways in the execution of the maternal program of apoptosis in Xenopus embryos; one being through do novo expression of caspase-8 gene during cleavage stage, and the other without involvement of caspase-8.

Original languageEnglish
Pages (from-to)682-691
Number of pages10
JournalBiochemical and Biophysical Research Communications
Volume336
Issue number2
DOIs
Publication statusPublished - Oct 21 2005
Externally publishedYes

Keywords

  • Caspase-8
  • Caspase-9
  • Dominant-negative caspases
  • Maternal program of apoptosis
  • Overexpression of SAMDC
  • Pre-MBT transcription
  • Xdm-2
  • Xenopus laevis embryos
  • p53

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Occurrence of pre-MBT synthesis of caspase-8 mRNA and activation of caspase-8 prior to execution of SAMDC (S-adenosylmethionine decarboxylase)- induced, but not p53-induced, apoptosis in Xenopus late blastulae'. Together they form a unique fingerprint.

  • Cite this