In zebrafish eggs, most rapidly growing cell inhibits neighbors through mechanical signals
"The winner takes it all, the loser standing small"—that's not just true in the famous ABBA song, but also in animal development. Frequently, a group of cells starts out all being the same. But then one cell puts the brake on its neighbors, sending inhibitory signals that stop their differentiation. The "winning" cell, in the end, is different from its neighbors. So far, the only signalling mechanism known to be responsible for such a lateral inhibition was the Notch-Delta signalling pathway. Postdoc Peng Xia and Professor Carl-Philipp Heisenberg at the Institute of Science and Technology Austria (IST Austria), have now described a new mechanism for lateral inhibition in a publication in today's edition of Cell. In zebrafish ovarian follicles, granulosa cells in the envelope that surround the oocyte do not use the Notch-Delta signaling pathway for lateral inhibition, but compete mechanically—the winning cell grows more rapidly and inhibits the growth...