The induction of de novo centrioles in sea urchin eggs: a possible common mechanism for centriolar activation among parthenogenetic procedures
Kallenbach, R.J.
European Journal of Cell Biology 30(2): 159-166
1983
ISSN/ISBN: 0171-9335 PMID: 11596489 Document Number: 206991
Eggs from 2 spp. of sea urchins . These treatments readily resulted in the formation of cytasters and centrioles. Centrioles are restricted to the cytasters, and the broad perinuclear zone; it appears that all cytasters contain 1 or more centrioles. The mode of centriolar origin and maturation, as revealed by these new procedures, is identical to that of centrioles induced by other procedures. Centriolar and cytastral development are retarded by the parthenogenetic treatments; also, mitosis is generally delayed. Parthenogenetic agents have opposing effects on eggs. The agents are stimulatory in that they activate latent centrioles and the cell cycle, in general. They are inhibitory in that they suppress a variety of physiochemical events. Of these events, only 1 appears to be common to all parthenogenetic agents: the inhibition of protein synthesis. Egg centrioles may be kept in a latent state by repressor proteins. If these proteins normally cycle rapidly, then an inhibition of their continuous synthesis will disrupt their normal replacement rate. As such, a delay in replacement will allow functioning repressor proteins, associated with latent centrioles, to become nonfunctional, which in turn allows latent centrioles to become derepressed. This deblocking reaction would then activate the appearance of de novo centrioles in eggs.