PT  - JOURNAL ARTICLE
AU  - Camuglia, Jaclyn
AU  - Chanet, Soline
AU  - Martin, Adam C
TI  - Morphogenetic forces planar polarize LGN/Pins in the embryonic head during <em>Drosophila</em> gastrulation
AID  - 10.1101/2022.01.07.475359
DP  - 2022 Jan 01
TA  - bioRxiv
PG  - 2022.01.07.475359
4099  - http://biorxiv.org/content/early/2022/05/11/2022.01.07.475359.short
4100  - http://biorxiv.org/content/early/2022/05/11/2022.01.07.475359.full
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, depletion of an adherens junction protein or blocking mesoderm invagination disrupted Pins planar polarity and spindle orientation. Furthermore, directional ablations that separated mesoderm from mitotic domains disrupted spindle orientation, suggesting that forces transmitted from mesoderm to mitotic domains can polarize Pins and orient division during gastrulation. 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.