Cytokinesis proceeds asymmetrically in C. elegans with the furrow invaginating first on one side and then shifting to the other side of the cell, report Audhya et al. on page 267. This taking of turns, and the structural mechanism that enforces it, may ensure that the furrow is localized in a single plane.
The asymmetry came to light when the authors studied CAR-1, which was previously identified in an RNAi study as being required for embryonic cytokinesis. Audhya et al. show that CAR-1 helps regulate maternally supplied RNAs in the germline and early embryo.
These RNAs are apparently required to assemble and maintain functional interzonal microtubules, which form between the separating chromosomes after anaphase. To get a picture of the resulting cytokinesis defect, the team expressed a GFP construct that specifically binds to the lipids of the plasma membrane.
In wild-type worms, the furrow...
