Gap junctions between the follicle cells and the oocyte during oogenesis in an insect,Tribolium destructor/Coleoptera

Summary Oocyte-follicle cell gap junctions inTribolium occur in all oogenetic stages studied. During early previtellogenesis the junctions are found exclusively between lateral membranes of oocyte microvilli and the membrane of prefollicle cells. In late previtellogenesis and vitellogenesis the junctions are located between the tips of oocyte microvilli and the flat membranes of the follicle cells. During previtellogenesis gap junctions are infrequent, whereas in the phase of yolk accumulation their number increases considerably, exceeding 17 junctions/m² of the follicle cell membrane. It could be shown by microinjection of a fluorescent dye that gap junctions are in a functional state during vitellogenesis. Possible roles of heterologous gap junctions in oogenesis are discussed.