Effect of taxol on first and second meiotic spindle formation in oocytes of the surf clam, Spisula solidissima.

Purification and characterization of oocyte cytoplasmic tubulin and meiotic spindle tubulin of the surf clam Spisula solidissima

Assembly-competent tubulin was purified from the cytoplasm of unfertilized and parthogenetically activated oocytes, and from isolated meiotic spindles of the surf clam, Spisula solidissima. At 22 degrees C or 37 degrees C, Spisula tubulin assembled into 48-51-nm macrotubules during the first cycle of polymerization and 25-nm microtubules during the third and subsequent cycles of assembly. Macro...

Changes in the Organization of Tubulin during Meiosis in the Eggs of the Surf Clam, Spisula Solidissima

Polymerized tubulin can be stabilized in Kane's spindle isolation medium (HGL solution), isolated by differential centrifugation and then assayed by colchicine binding activity. In the eggs of the surf clam, Spisula solidissima, the level of particulate tubulin undergoes a series of specific changes during first meiotic division. In either unactivated ("interphase") eggs or metaphase eggs the a...

Rediscovery of the nucleolinus, a dynamic RNA-rich organelle associated with the nucleolus, spindle, and centrosomes.

The nucleolinus is an RNA-rich compartment, closely apposed to or embedded within the nucleolus. Discovered over 150 y ago, fewer than two dozen articles have been published on the nucleolinus, probably because complex histochemical stains are required for its visualization in the great majority of cells. The nucleolinus has been reported in invertebrate oocytes, mammalian and amphibian epithel...

Isolation of Spindles from the Surf Clam Spisula Solidissima

The small organic compound HMN-176 delays satisfaction of the spindle assembly checkpoint by inhibiting centrosome-dependent microtubule nucleation.

HMN-176 is a potential new cancer therapeutic known to retard the proliferation of tumor cell lines. Here, we show that this compound inhibits meiotic spindle assembly in surf clam oocytes and delays satisfaction of the spindle assembly checkpoint in human somatic cells by inducing the formation of short and/or multipolar spindles. HMN-176 does not affect centrosome assembly, nuclear envelope b...