Activation at the germinal vesicle stage of starfish oocytes produces parthenogenetic development through the failure of polar body extrusion.
Starfish oocytes can be fertilized after germinal vesicle breakdown (GVBD) and artificial parthenogenesis can be induced by activating the oocytes after GVBD (post-GVBD activation). In the present study, parthenogenotes were obtained by the activation of immature oocytes with caffeine before treatment with 1-methyladenine (1-MeAde) to induce oocyte maturation. Most of the caffeine-treated eggs developed as tetraploids, as parthenogenotes produced by the post-GVBD activation. The parthengenotes were derived only from eggs that failed to extrude polar bodies, mostly from eggs failing to extrude a second polar body. Eggs derived from immature oocytes activated by A23187, treated with 1-MeAde and post-treated with cytochalasin B failed to extrude polar bodies, and eventually developed into parthenogenetic embryos. These results indicate that the present parthenogenesis mechanism shares the same characteristics as that achieved by post-GVBD activation in the suppression of polar body formation as a key means for successful starfish parthenogenesis.
Washitani-Nemoto
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Biological Laboratory, Hitotsubashi University, Tokyo, Japan.
Nemoto
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D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D003571:Cytochalasin B / Q000494:pharmacology; D005260:Female; D007476:Ionophores / Q000494:pharmacology; D009865:Oocytes / Q000187:drug effects / Q000254:growth & development*; D010312:Parthenogenesis / Q000187:drug effects / Q000235:genetics; D011123:Polyploidy; D013215:Starfish / Q000196:embryology* / Q000235:genetics / Q000502:physiology
D007476:Ionophores; D000001:Calcimycin; D003571:Cytochalasin B; D002110:Caffeine; C008407:1-methyladenine; D000225:Adenine