Figure 3.

The initial segregation of sensory and motor cells of origin into ophthalmic, maxillary and mandibular projecting populations is not substantially disrupted by 22q11.2 gene deletion during the initial differentiation of CN V. (A) Broad field image of injections of 3 distinct fluorophore-conjugated biocytins into the target territories of the op (blue), mx (red) and md (green) branches of CN V in a WT E11.5 embryo. The region of CNgV is indicated by a dotted circle, and the adjacent hindbrain (HB), the site of md-projecting CN V motor neurons, is outlined by dotted lines. (B, C) Two examples of WT CNgV showing segregation of op (blue), mx (red) and md (green) projecting CN V sensory neurons. (D–F) Digitally enlarged images of individual retrogradely labeled CN V sensory neurons that project to op, mx and md territories. (G) Localized labeling of CN V motor neurons projecting via the md branch, in the WT hindbrain. (H, I) Retrogradely labeled op (blue), mx (red) and md (green) CN V sensory neurons are segregated in LgDel^+/− E11.5 embryos, similar to that in WT, following biocytin injection into respective target territories. (J–L) Digitally enlarged images of individual retrogradely labeled op (blue), mx (red) and md (green) LgDel^+/− CN V sensory neurons. (M) Similar location and segregation of md-projecting CN V motor neurons in the hindbrain adjacent to CNgV in LgDel^+/− embryos. (N–P) Combined retrograde labeling of CN V sensory neurons following Ba1B (md) injection (green, left) with immunohistochemical labeling for markers associated with differentiating sensory neurons that extend axons (Brn3A, red, middle, N); cranial placode derived CN V sensory neurons (Six1, red, middle, O) or rhombomere 2/3 neural crest derived sensory neurons/precursors (Sox10, red, middle, P). The retrogradely labeled CN V neurons express Brn3A and Six1 (yellow label, right, N, O), but not Sox10 (almost no registration between red and green label, right, P).