Sci. STKE, 5 September 2006
DEVELOPMENT This End Up
In early embryo development, polarity is established as early as the one-cell stage, when sperm entry triggers the asymmetric distribution of proteins and generation of an anteroposterior axis. Jenkins et al. now report the identity of a sperm-donated factor that affects protein polarity and the actomyosin cytoskeleton within the early nematode embryo. At fertilization, the sperm contributes CYK-4 protein to the egg. Proteins that participate with CYK-4 for polarity initiation include RHO-1, a member of the RhoA family of guanosine triphosphatases (GTPases), and ECT-2, a guanine nucleotide exchange factor. CYK-4 is a GTPase activating protein. ECT-2 and RHO-1 proteins promote, but CYK-4 inhibits, activated myosin light chain and actomyosin contractility. Because CYK-4 is expressed in sperm of other species, it will be of interest to know whether this polarity mechanism is conserved among other species that display actomyosin contraction.
Citation: This End Up. Sci. STKE 2006, tw309 (2006).
Science Signaling. ISSN 1937-9145 (online), 1945-0877 (print). Pre-2008: Science's STKE. ISSN 1525-8882