PT - JOURNAL ARTICLE AU - Kenji Sugioka AU - Bruce Bowerman TI - Cell-nonautonomously tunable actomyosin flows orient distinct cell division axes AID - 10.1101/164186 DP - 2017 Jan 01 TA - bioRxiv PG - 164186 4099 - http://biorxiv.org/content/early/2017/07/17/164186.short 4100 - http://biorxiv.org/content/early/2017/07/17/164186.full AB - Cell division axes during animal development are arranged in diverse orientations, but the molecular mechanisms underlying this diversity remain unclear. By focusing on oriented divisions that are independent of known microtubule/dynein pathways, we show here that the non-muscle myosin II motor is an extrinsically tunable force generator that orients cell division axes through cortical actomyosin flows. We identified three extracellular cues that generate different actomyosin flows. A single contact site locally inhibited myosin activity in a mechanosensitive manner to generate local flow asymmetry, while size asymmetry of two contact sites and Wnt signaling both polarized myosin activity and actomyosin flow, with the latter overriding mechanosensitive effects. These intracellular actomyosin flow anisotropies specify distinct division axes to establish the geometries of not only Caenorhabditis elegans 4-, 6-, and 7-cell stage but also mouse 4-cell stage embryos. Tunable actomyosin flows together with microtubule/dynein pathways may specify diverse division axes across species.Highlights Mechanosensitive actomyosin flow orients cell division independent of microtubules.Extrinsic Wnt signal abrogates mechanosensitive effects on cortical flow.Patterns of cell contact establish mouse and C. elegans embryonic geometries.