Centrosome duplication continues in cycloheximide-treated Xenopus blastulae in the absence of a detectable cell cycle.
Cycloheximide (500 micrograms/ml) rapidly arrests cleavage, spindle assembly, and cycles of an M-phase-specific histone kinase in early Xenopus blastulae. 2 h after cycloheximide addition, most cells contained two microtubule asters radiating from perinuclear microtubule organizing centers (MTOCs). In contrast, blastomeres treated with cycloheximide for longer periods (3-6 h) contained numerous microtubule asters and MTOCs. Immunofluorescence with an anticentrosome serum and EM demonstrated that the MTOCs in cycloheximide-treated cells were typical centrosomes, containing centrioles and pericentriolar material. We conclude that centrosome duplication continues in cycloheximide-treated Xenopus blastulae in the absence of a detectable cell cycle. In addition, these observations suggest that Xenopus embryos contain sufficient material to assemble 1,000-2,000 centrosomes in the absence of normal protein synthesis.
Department of Biology, University of Utah, Salt Lake City.
D L
DL
Gard
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S
Hafezi
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Zhang
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SJ
Doxsey
D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002502:Centrioles / Q000187:drug effects / Q000502:physiology*; D003513:Cycloheximide / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D007399:Interphase; D008870:Microtubules / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D008941:Spindle Apparatus / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014982:Xenopus laevis / Q000196:embryology*
D003513:Cycloheximide