Figure 3

Increased development of hemiadherens junctions (HAJs) and apical extracellular matrix (AECM) in upper oviduct after mating. (A and E) Drawing of upper oviduct in cross section (traced from electron micrographs). Lumen (L) is barely visible in unmated (A) as compared to mated (E) oviduct. However, note the infolding of the basolateral membrane (outlined in yellow) in both unmated and mated. EP (epithelium); M (muscle). Electron micrographs of region outlined by box shown in B and F. (B and F) Basolateral infolding gives rise to an intercellular space with short branches (yellow). Apical surface is covered by an electron dense layer of matrix (black *) and thin layer of cuticle (arrow). The ruffled appearance of the cuticle (arrows in F) suggests an increase in surface area after mating. Note the presence of a granule (white*) in the cytoplasm. N (nuclei). Area outlined by box shown in C and G. Bar is 2 μm. (C and G) HAJs appear as electron dense patches underneath the plasma membrane. Note the absence of HAJs along the basolateral membrane (arrow) in unmated (C), and the abundance of HAJs (arrowheads), as well as mitochondria (mt) in mated (G). Bar is 200 nm. (D and H) Tracing of basolateral infolding highlights the appearance of HAJs after mating. Note also the increased width of the intercellular space in the mated oviduct (97.8 ± 12.4 μm versus 54.4 ± 11.7 μm). Schematic of the female reproductive tract showing the region of origin of the cross sections (dashed line, LO = lateral oviducts).