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Fig. 4. Species comparison of Noelin-1/2 expression. (A) Dorsal view of a stage 22 frog embryo (approximately 10-somite stage) stained with Noelin-1/2
reveals transcripts in the developing trigeminal ganglia and spinal cord, but not in the neural crest (anterior is to the right). (B) A transverse section through the
rostral trunk reveals staining in developing neuron populations (arrowheads; section is counterstained with Light Green). (C) Dorso-lateral view of a stage 20
frog embryo stained with the neural crest marker XSlug reveals the location of neural crest cells at this stage (neural crest masses: m, mandibular; h, hyoid; b,
branchial). (D) A stage 28 frog embryo stained with Noelin-1/2. Staining is found in cranial ganglia, the pineal gland and in the spinal cord. Cranial neural crest
streams do not express Noelin-1/2 (locations of streams are noted in (D) and (E) m, mandibular; h, hyoid; ba, anterior branchial, bp, posterior branchial). (E)
The neural crest marker XTwist reveals neural crest cells migrating into the branchial arches. (F) A 10-somite chick embryo with Noelin expression in the
migrating neural crest in the midbrain region and in the neural tube from the hindbrain through the open neural plate. (G) A stage 18 chick embryo stained with
Noelin. Note the Noelin expression in the anterior region of the chick limb bud, as opposed to the mouse in (H) which has Noelin staining in the posterior limb
bud. Chick photos are courtesy of M. Barembaum. (H) A mouse E10 embryo stained with Noelin-1/2 for comparison to the frog and chick patterns. The tail is
curved toward the viewer, causing the anterior/posterior axis of the limb to appear backwards. cg, cement gland; e, eye; fl, forelimb; hl, hindlimb; IN,
interneurons; mb, midbrain; MN, motor neurons; np, neural plate; o, olfactory placode; V, trigeminal ganglion; VII, geniculate ganglion; sc, spinal cord;
asterisks denote otic vesicles. |
