Injection of isolated centriolar complex to induce mitosis in starfish eggs

When centriolar complex isolated from starfish spermatozoa was injected into starfish immature oocytes (fully grown, germinal vesicle stage) followed by treating the latter with 1‐methyladenine, mitotic events such as condensation and division of chromosomes of the female pronucleus and cytokinesis following completion of meiosis were observed. No cortical reaction detected in the oocytes. Essentially the same was noted for mature oocytes (pronuclear stage) into which the centriolar complex had been injected. The oocytes that had received sperm tail fraction or buffer alone did not initiate cleavage. It would thus appear that sperm centriolar complex is significantly essential to the initiation of cleavage.