Microinjection of antibodies to a 62 kd mitotic apparatus protein arrests mitosis in dividing sea urchin embryos. Academic Article uri icon


  • Previously, we described a 62 kd protein that is a component of the isolated sea urchin mitotic apparatus. This protein is a substrate for an endogenous, calcium/calmodulin-dependent protein kinase also associated with the mitotic apparatus. Phosphorylation of the 62 kd protein directly correlates with the depolymerization of microtubules in isolated mitotic apparatuses. Here we report a test of the function of the 62 kd protein in vivo. Double labeling studies using a monoclonal antibody to tubulin and an affinity purified antibody specific for the 62 kd protein reveal that the 62 kd protein co-localizes with mitotic apparatus microtubules. When affinity purified antibodies to the 62 kd protein were microinjected into dividing sea urchin embryos, mitosis was blocked in a stage-specific manner. The results are discussed with respect to the role of the 62 kd protein in the metaphase-anaphase transition.

publication date

  • April 7, 1989

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