A microtubule-organizing center directing intracellular transport in the early mouse embryo

How microtubules organize in embryos Cell functions ranging from cell division to morphogenesis rely on microtubules, with microtubule-organizing centers serving as anchoring sites for their outgrowth. Although the centrosome organizes the microtubule cytoskeleton in most animal cells, this organelle is absent in early development. Using live-cell imaging, Zenker et al. found that the cells of the early mouse embryo are connected by stable microtubule bridges to direct the growth of microtubules within them. Microtubules emanating from the bridges help to guide transport of key proteins, including E-cadherin, to the cell membrane to control cell polarization during early development. Science , this issue p. 925