jagged1b expression pattern. In situ hybridization of embryos at different developmental stages performed with the jagged1b probe. A: At the 10-somite stage (10s), jagged1b is expressed in the notochord and the pronephros primordia. B-D: At the 20-somite stage, jagged1b-expressing cells are detected mainly in the lens, otic vesicles, and two bilateral groups of cells situated anteriorly and posteriorly to the latter (B), in the caudal part of the notochord (C), and in the rostral part of the pronephric ducts (D). C: At the 20-somite stage, jagged1b transcripts are detected in a group of cells located ventrally and posteriorly to the anus. E: At 24 hours postfertilization (hpf), jagged1b and pax2a are coexpressed in cells of the rostral end of the pronephric duct and lateral part of the nephron primordia, but only jagged1b is expressed in the medial cells of the nephron primordia. F: At the same stage, jagged1b transcripts are also expressed in the region extending from the otic vesicle to the eye. G,H: At 28 hpf, the jagged1b (arrow) expression domain does not overlap with that of glucagon in the pancreatic islet (G), but is in part overlapped with the pdx1 expression domain (H). Views are dorsal (A,B,F), lateral (C,H), or ventral (D,E,G). Anterior is to the left in all pictures. a, anus; ep, endocrine pancreas; l, lens; n, notochord; np, nephron primordia; ov, otic vesicle; pd, pronephric duct; pdp, pronephric duct primordium; r3, rhombomere 3; r5, rhombomere 5.