ISOLATION OF ACTIN-ASSOCIATED PROTEINS FROM CAENORHABDITIS-ELEGANS OOCYTES AND THEIR LOCALIZATION IN THE EARLY EMBRYO

The actin cytoskeleton plays an important, but poorly understood, role in the development of multicellular organisms. To help illuminate thi s role, we used actin filament affinity chromatography to isolate acti n binding proteins from large quantities of Caenorhabditis elegans ooc ytes. To examine how these proteins might be involved in early develop ment, we prepared antibodies against some of them and determined their distribution in fixed embryos. Three of these proteins co-localize wi th different subsets of the embryonic actin cytoskeleton. One co-local izes with actin to all cell cortices. The second oscillates between th e nucleus and cortex in a cell-cycle-dependent manner. The third is as ymmetrically enriched at the anterior cortex of one-cell embryos, show ing a temporal and spatial localization suggestive of a function in ge nerating developmental asymmetry. We conclude that biochemistry is a f easible and useful approach in the study of early C. elegans developme nt, and that the embryonic actin cytoskeleton is regulated in a comple x fashion in order to carry out multiple, simultaneous functions.