Accumulation of WGA receptors in the cleavage furrow during cytokinesis of sea urchin eggs.
Sea urchin eggs stained with fluorescein-conjugated wheat germ agglutinin (F-WGA) before or after fixation showed a marked accumulation of fluorescence at the cleavage furrow in the first and the second cell divisions. WGA receptors (WGA-binding membrane glycoproteins) were redistributed to the equatorial region through several steps in compressed eggs. Accumulated WGA receptors showed a distribution similar to that of contractile-ring microfilaments throughout most of the steps. Therefore, the former is probably associated with the latter directly or indirectly. Labeling with F-WGA provides a simple method to detect contractile-ring microfilaments in living eggs. Treatment of eggs with colcemid shortly before cytokinesis dispersed the ring-like accumulation of WGA receptors together with contractile-ring microfilaments. This result suggests that microtubule structures, probably asters, are involved in the redistribution of WGA receptors. Cytochalasin B prevented furrowing when it was applied shortly before cytokinesis. While contractile-ring microfilaments showed a spotty distribution in the expected furrow region, WGA receptors were normally redistributed. Furthermore, a higher concentration of the drug allowed the appearance of accumulated WGA receptors in compressed eggs although the development into a ring-like configuration was inhibited. These observations suggest the possibility that the redistribution of WGA receptors is involved in the formation of contractile ring.
Yoshigaki
T
T
Department of Biology, College of Arts and Sciences, University of Tokyo, Japan.
D008841:Actin Cytoskeleton / Q000187:drug effects; D000818:Animals; D002451:Cell Compartmentation; D002455:Cell Division / Q000502:physiology*; D003571:Cytochalasin B / Q000494:pharmacology; D003703:Demecolcine / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D010063:Ovum; D011975:Receptors, Mitogen / Q000378:metabolism*; D012617:Sea Urchins
D008565:Membrane Proteins; D011975:Receptors, Mitogen; C027503:wheat germ agglutinin receptor; D003571:Cytochalasin B; D003703:Demecolcine