Temporally different poly(adenosine diphosphate-ribosylation) signals are required for DNA replication and cell division in early embryos of sea urchins.
To analyze the temporal relationship of poly(adenosine diphosphate [ADP]-ribosylation) signal with DNA replication and cell divisions, the effect of 3 aminobenzamide (3ABA), an inhibitor of the poly(ADP-ribose)synthetase, was determined in vivo during the first cleavage division of sea urchins. The incorporation of 3H-thymidine into DNA was monitored and cleavage division was examined by light microscopy. The poly(ADP-ribose) neosynthesized on CS histone variants was measured by labeling with 3H-adenosine during the two initial embryonic cell cycles and the inhibitory effect of 3ABA on this poly(ADP-ribosylation) was determined. The results obtained indicate that the CS histone variants are poly(ADP-ribosylated) de novo during the initial cell cycles of embryonic development. The synthesis of poly(ADP-ribose) is decreased but not abolished by 20 mM of 3ABA. The incubation of zygotes in 3ABA at the entrance into S1 phase decreased 3H-thymidine incorporation into DNA in phase S2, while S1 was unaltered. Alternatively, when the same treatment was applied to zygotes at the exit of S1 phase, a block of the first cleavage division and a retardation of S2 phase were observed. The inhibitory effect of 3ABA on both DNA replication and cell division was totally reversible by a release of the zygotes from this inhibition. Taking together these observations it may be concluded that the poly(ADP-ribosylation) signals related to embryonic DNA replication are not contemporaneous with S phase progression but are a requirement before its initiation.(ABSTRACT TRUNCATED AT 250 WORDS)
Imschenetzky
M
M
Department of Molecular Biology, Universidad de Concepción, Chile.
Montecino
M
M
Puchi
M
M
D000818:Animals; D001549:Benzamides / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D004261:DNA Replication / Q000187:drug effects / Q000502:physiology*; D006657:Histones / Q000378:metabolism; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011065:Poly(ADP-ribose) Polymerases / Q000096:biosynthesis / Q000502:physiology*; D016196:S Phase / Q000187:drug effects / Q000502:physiology; D012617:Sea Urchins / Q000166:cytology / Q000196:embryology; D015398:Signal Transduction / Q000502:physiology*; D013997:Time Factors
D001549:Benzamides; D006657:Histones; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; C025160:3-aminobenzamide; D011065:Poly(ADP-ribose) Polymerases