Tissue-Specific Functions of fem-2/PP2c Phosphatase and fhod-1/formin During Caenorhabditis elegans Embryonic Morphogenesis

摘要

The cytoskeleton is the basic machinery that drives many morphogenetic events. Elongation of the C. elegans embryo from a spheroid into a long, thin larva initially results from actomyosin contractility, mainly in the lateral epidermal seam cells, while the corresponding dorsal and ventral epidermal cells play a more passive role. This is followed by a later elongation phase involving muscle contraction. Early elongation is mediated by parallel genetic pathways involving /Rho kinase and /MYPT myosin phosphatase in one pathway and /PP2c phosphatase and /p21 activated kinase in another. While the / pathway appears to act primarily in the lateral epidermis, here we show that can mediate early elongation when expressed in the dorsal and ventral epidermis. We also investigated the early elongation function of , a member of the formin family of actin nucleators and bundlers. Previous work showed that acts in the / branch of the early elongation pathway as well as in muscle for sarcomere organization. Consistent with this, we found that lateral epidermal cell-specific expression of is sufficient for elongation, and effects on elongation appear to be independent of its role in muscle. Also, we found that encodes long and short isoforms that differ in the presence of a predicted coiled-coil domain. Based on tissue-specific expression constructions and an isoform-specific CRISPR allele, the two isoforms show partially specialized epidermal or muscle function. Although shows only impenetrant elongation phenotypes, we were unable to detect redundancy with other C. elegans formin genes.