FIG. 1.

A 3-dimensional projection of a whole mount of a healthy mouse pancreas and visualization of the peri-islet capsule by immunofluorescence staining and electron microscopy are shown. A: Insulin⁺ and glucagon⁺ pancreatic islets are encased in the peri-islet BM. B: An optical section of a 3-dimensional projection of a whole-mount pancreatic islet shows in a simultaneous view of XY, XZ, and YZ planes, illustrating the peri-islet BM and endothelial BMs. Differential localization of laminin (LM) α4 and α5 chains in the pancreatic islet is shown by immunofluorescence staining of thin sections (C) and whole-mount staining (D). C: Meca32 staining marks the endothelial layer of blood vessels (insets show images at higher magnification). E: Collagen type III staining visualizes the IM of the peri-islet capsule that underlies the peri-capsular BM, marked by pan-laminin (PLM) staining. F: Electron micrography illustrates two BMs: the peri-islet BM (arrow) that envelops the β-cells and the endothelial BM of blood vessels (arrowhead; inset 1). Subjacent to peri-islet BM (arrow), fibrillar collagens are evident (*; inset 2). Scale bars are 100 μm for A–E,50 μm for insets in C, and 1 μm in F. (A high-quality digital representation of this figure is available in the online issue.)