Poly(ADP-ribosylation) protects maternally derived histones from proteolysis after fertilization

Violeta Morin, Freddy Diaz, Martin Montecino, Linda Fothergill-Gilmore, Marcia Puchi, Maria Imschenetzky

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)


Fertilization in sea urchins is followed by the replacement of sperm-specific histones by cleavage-stage histone variants recruited from maternal stores. Such remodelling of zygote chromatin involves a cysteine proteinase that degrades the sperm-specific histones in a selective manner, leaving the maternal cleavage-stage histone variants intact. The mechanism that determines the selectivity of the sperm-histone-selective proteinase (SpH-proteinase) was analysed by focusing on the post-translational modification status of both sets of histones. It has previously been reported that only native cleavage-stage histones are poly(ADP-ribosylated), whereas the sperm-specific histones are not modified. To determine whether the poly(ADP-ribose) moiety afforded protection from degradation, the ADP-ribose polymers were removed from the cleavage-stage histones in vitro; these proteins were then assayed as potential substrates of the SpH-proteinase. Strikingly, the cleavage-stage histone variants were extensively degraded after the enzymic removal of their ADP-ribose moieties. In addition, the SpH cysteine proteinase was not inhibited by isolated poly(ADP-ribose) polymers. Consequently, only poly(ADP-ribosylated) cleavage-stage histone variants are protected from proteolysis. These results demonstrate a novel role for this type of post-translational modification, namely the protection of nuclear proteins against nuclear proteinases after fertilization.

Original languageEnglish
Pages (from-to)95-98
Number of pages4
JournalBiochemical Journal
Issue number1
Publication statusPublished - 1 Oct 1999


  • Chromatin
  • Cysteine-proteinase
  • Pronucleus
  • Sea urchins
  • Zygotes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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