RT Journal Article SR Electronic T1 Morphogenetic forces planar polarize LGN/Pins in the embryonic head during Drosophila gastrulation JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.01.07.475359 DO 10.1101/2022.01.07.475359 A1 Jaclyn Camuglia A1 Soline Chanet A1 Adam C Martin YR 2022 UL http://biorxiv.org/content/early/2022/01/07/2022.01.07.475359.abstract AB Spindle orientation is often achieved by a complex of Pins/LGN, Mud/NuMa, Gαi, and Dynein, which interacts with astral microtubules to rotate the spindle. Cortical Pins/LGN recruitment serves as a critical step in this process. Here, we identify Pins-mediated planar cell polarized divisions in several of the mitotic domains of the early Drosophila embryo. We found that neither planar cell polarity pathways nor planar polarized myosin localization determined division orientation; instead, our findings strongly suggest that Pins planar polarity and force generated from mesoderm invagination are important. Disrupting Pins polarity via overexpression of a myristoylated version of Pins caused randomized division angles. We found that disrupting forces through chemical inhibitors, laser ablation, and depletion of an adherens junction protein disrupted Pins planar polarity and spindle orientation. Furthermore, snail depletion, which abrogates ventral furrow forces, disrupted Pins polarization and spindle orientation, suggesting that morphogenetic movements and resulting forces transmitted through the tissue can polarize Pins and orient division. Thus, morphogenetic forces associated with mesoderm invagination result in planar polarized Pins to mediate division orientation at a distant region of the embryo during morphogenesis. To our knowledge, this is the first in vivo example where mechanical force has been shown to polarize Pins to mediate division orientation.Competing Interest StatementThe authors have declared no competing interest.