The origin and fate of secretion in the follicle cells of tunicates

Summary The vacuolization of the outer follicle cells which accompanies maturation of the oocytes of the tunicates Ciona intestinalis and Molgula manhattensis is associated with the dissolution of heterogeneous secretion granules in these cells. The secretion granules, in turn, have a dual origin with one component derived from the endoplasmic reticulum while the other component arises in association with the Golgi complexes. Stages in the morphogenesis of secretion are described.This study was supported by a research grant (GM-09229) and a Career Development Award from the National Institute of General Medical Science, United States Public Health Service.