Getting into shape: epidermal morphogenesis in Caenorhabditis elegans embryos.

The change in shape of the C. elegans embryo from an ovoid ball of cells into a worm-shaped larva is driven by three events within the cells of the hypodermis (epidermis): (1) intercalation of two rows of dorsal cells, (2) enclosure of the ventral surface by hypodermis, and (3) elongation of the embryo. While the behavior of the hypodermal cells involved in each of these processes differs dramatically, it is clear that F-actin and microtubules have essential functions in each of these processes, whereas contraction of actomyosin structures appears to be involved specifically in elongation. Molecular analysis of these processes is revealing components specific to C. elegans as well as components found in other systems. Since C. elegans hypodermal cells demonstrate dramatically different behaviors during intercalation, enclosure and elongation, the study of cytoskeletal dynamics in these processes may reveal both unique and conserved activities during distinct epithelial morphogenetic movements. BioEssays 23:12-23, 2001.