Figure 3.

ngn3 is required for the differentiation of the four pancreatic endocrine cell lineages. Islets of Langerhans (arrows in a) and cells expressing insulin (b and f), glucagon (c, g, arrowheads in h), somatostatin (d), PP (e), and Isl1 (arrowheads in i) are observed in wild-type pancreas (a–h) but are completely missing in ngn3 mutant pancreas at birth (compare a–e with a′–e′) and also missing at early stages of differentiation: E15.5 (f, f′, g, and g′), E10.5 (i and i′), and E9.5 (h and h′). (a and a′) Hematoxylin-eosin (HE) staining.