Microinjection of antibodies to a 62 kd mitotic apparatus protein arrests mitosis in dividing sea urchin embryos.
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.
Dinsmore
J H
JH
Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755.
Sloboda
R D
RD
D000818:Animals; D000906:Antibodies / Q000008:administration & dosage / Q000494:pharmacology*; D000918:Antibody Specificity; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D007150:Immunohistochemistry; D008845:Microinjections; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D008938:Mitosis / Q000187:drug effects*; D010766:Phosphorylation; D012617:Sea Urchins / Q000166:cytology*; D008941:Spindle Apparatus / Q000032:analysis
D000906:Antibodies; D008869:Microtubule-Associated Proteins