PATTERNS OF INTERCELLULAR CONNECTIVITY IN THE MAMMALIAN CUMULUS-OOCYTE COMPLEX

Electron and fluorescence microscopic techniques have been used in a c omplementary fashion to study the patterns of follicle cell-oocyte int eractions within cumulus-oocyte-complexes of various mammals. The prin cipal findings are: (1) two distinct types of transzonal processes exi st that are distinguishable on the basis of cytoskeletal composition; (2) in some of the species examined (pig, goat, primate), corkscrew-sh aped processes rich in tubulin, traverse the zona pellucida and are in vaginated into the oocyte cortex; (3) actin-rich processes either rami fy as a network at the outer surface of the zona pellucida or penetrat e the zona and make contact with the oolemma in a species specific man ner. These results are discussed with respect both to the need to empl oy complementary optical methods in assessing connectivity patterns wi thin COC and to the possible role that extracellular matrix-cell inter actions play in the homeostatic control of oocyte growth and maturatio n.