Optogenetic dissection of mitotic spindle positioning in vivo.

ABSTRACT: The position of the mitotic spindle determines the plane of cell cleavage, and thereby daughter cell location, size, and content. Spindle positioning is driven by dynein-mediated pulling forces exerted on astral microtubules, which requires an evolutionarily conserved complex of G??GDP, GPR-1/2^Pins/LGN, and LIN-5^Mud/NuMA proteins. To examine individual functions of the complex components, we developed a genetic strategy for light-controlled localization of endogenous proteins in C. elegans embryos. By replacing G? and GPR-1/2 with a light-inducible membrane anchor, we demonstrate that G??GDP, G??GTP, and GPR-1/2 are not required for pulling-force generation. In the absence of G? and GPR-1/2, cortical recruitment of LIN-5, but not dynein itself, induced high pulling forces. The light-controlled localization of LIN-5 overruled normal cell-cycle and polarity regulation and provided experimental control over the spindle and cell-cleavage plane. Our results define G??GDP-GPR-1/2^Pins/LGN as a regulatable membrane anchor, and LIN-5^Mud/NuMA as a potent activator of dynein-dependent spindle-positioning forces.

SUBMITTER: Fielmich LE 

PROVIDER: S-EPMC6214656 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature