Gamete self‐discrimination in ascidians: A role for the follicle cells

Publisher Website
Google Scholar
Abstract
Gamete self‐incompatibility in the hermaphrodite tunicate Ciona intestinalis is a useful system with which to study self‐nonself recognition. We have used in vitro fertilization of oocytes isolated from the gonad of Ciona intestinalis to identify the cellular source of self‐sterility elements present on the egg envelopes. Here we show for the first time that self‐discrimination, which occurs on the egg vitelline coat, is established there in late oogenesis and is contributed or controlled by products of the overlying follicle cells. The acquisition of self‐sterility by the oocyte is prevented by the ionophore monensin, which suggests that the follicle cell self‐sterility controlling factor is a glycoprotein.