Identification of Genes Required for Spatial Control and Mechanical Resilience of Cytokinesis during Caenorhabditis elegans Embryogenesis

Abstract

Cytokinesis is the final step of cell division, in which the dividing cell is physically separated into two daughter cells by the contractile ring. The contractile ring is a highly resilient molecular machine that can function properly under mechanical stress. Additionally, its function, position, and orientation are spatially modulated in developing animals to regulate morphogenesis. Although essential regulators of cytokinesis have been identified through previous genetic screens, the molecular mechanisms underlying these spatial controls and the mechanical resilience of cytokinesis remain elusive. To identify cytokinesis regulators involved in these processes, we performed a high-throughput RNAi screen using a gain-of-function mutant of actin that exhibits ectopic cortical contraction and abnormal spatial control of cytokinesis in Caenorhabditis elegans embryos. We obtained a list of early embryonic genes that suppress embryonic lethality in an act-2 mutant background. Two parallel secondary screens of candidate genes were conducted. The first secondary screen in a wild-type background identified 69 candidate genes regulating spatial cytokinesis control--asymmetric ring closure, positioning, and rotation--during early embryogenesis. The second secondary screen in the act-2(or295) background identified four genes required for cytokinesis in this background, including microtubule regulators, evl-20/ARL2, and lpin-1/Lipin1. This study will serve as a useful resource for the development of future hypotheses and provide insights into the precise regulation of cytokinesis in tissues.