Fig 1.

Similarities of gene expression and mitotic status in pancreatic β cells and insulin-producing cells comprising stage 5NL IPCCs. (A–C) Dithizone staining of isolated pancreatic islets (A), stage 5NL IPCCs (B), and stage 5NB IPCCs (C). Magnification in A–C is equal. Images in D–R were obtained by confocal microscopy and are representative of at least 12 samples for each immunohistochemical probe. Samples were processed identically and in parallel for each immunohistochemical probe. Shown is simultaneous immunofluorescent detection of insulin and glucagon (D–F), α-fetoprotein (α-FP) (G–I), MAP2 (J–L), or β tubIII (M–O). In mature islets, there is localized expression of insulin and glucagon (D) but no detectable expression of α-FP (G) or the neuronal markers MAP2 (J) and β tubIII (M). Stage 5NL IPCCs cellular homogeneity (B, E, H, K, and N) contrasts with cellular heterogeneity of stage 5NB IPCCs (F, I, L, and O). (P–R) Immunofluorescent detection of Ki67, a nuclear marker of proliferating cells. Stage 5NL IPCCs (Q) are predominantly nonproliferating, similar to mature pancreatic islets (P), whereas stage 5NB culture conditions result in significant numbers of proliferating cells (R). Magnification in D–R is equal.