Fig. 5

Expression of cxcr4b during late zebrafish development. To confirm the identity of cxcr4b-positive cells in various areas of the CNS, we performed double staining using whole-mount in situ hybridization with the cxcr4b probe in combination with other neuronal markers as indicated on the figure. cxcr4b is expressed in the nucleus of the posterior commissure and locus coeruleus (A), as well as brachiomotor neurons of the hindbrain (B,C). The small box inserted in (B) shows an enlarged view of brachiomotor neurons. A cross-section level through r4 is shown in (G). Note the co-expression of cxcr4b and Islet-1 in the posterior part of the epiphysis (D). The lack of expression of cxcr4b in the anterior epiphysis (arrow), where only Islet-1 is expressed, implies that cells in the epiphysis undergo differentiation according to the same antero-posterior (A–P) time course as the rest of the CNS. (E,F) cxcr4b co-localizes with Islet-1 in trigeminal ganglion (tg) and Rohon–Beard cells (rb). In the eye (H–J), expression starts in the ventral patch and later continues in retinal ganglial cells. (K,L) The expression of cxcr4b is detected in the anterior (aht) and posterior hypothalamus (pht). (M) In the telencephalon (tc), the most intense expression was detected in the olfactory placode (op). In the dorsal diencephalon, expression occurs in the epiphysis (ep) and nuclei of posterior commissure (npc). bmn, brachiomotor neurons; ep, epiphysis; lc, locus coeroleus; ma, Mauthner neuron; op, olfactory placode; mhb, midbrain–hindbrain boundary; nmlf, nucleus of medial longitudinal fascicle; npc, nuclei of posterior commissure; pllo, primordium lateral line organ; r, rhombomeres; rgc, retinal ganglial cells; tc, telencephalon; vp, ventral patch; PTU, embryos treated with 1-phenyl-2-thiourea. Bar, 50 μm.