Figure 2
From: ISL1-based LIM complexes control Slit2 transcription in developing cranial motor neurons
Axon defects of cranial MNs in Isl1hypo/KO mice.
(A–D) Wholemount GFP immunostaining of E10.5 and E11.5 ISLMN: GFP-F reporter embryos. Oculomotor axons of Isl1hypo/KO mice are defasciculated at E10.5 (arrowhead, B). (E–L) Magnified views of images in (A–D). The trigeminal mandibular (V) nerves of Isl1hypo/KO mice are defasciculated (arrowhead in E,G vs arrowhead in F,H) and develop ectopic branches (open arrowheads, F,H). The facial nerve (VII) are fewer (arrows in E,G vs arrows in F,H) and the hypoglossal nerve (XII) is absent (arrow in I,K, arrow in J,L) (E10.5: n ≥ 3; E11.5: n ≥ 7; number of embryos). (M–P) Quantification of nerve length and thickness of axons. Error bars represent s.e.m. *p < 0.05, ***p < 0.001, unpaired Student’s t-test. (Q–T) Open-book flat-mount preparation of E11.5 hindbrains. IEE projections are short and disorganized in Isl1hypo/KO mice (arrowhead, T) (control: n = 5; Isl1hypo/KO mice: n = 3; number of embryos). (U,V) Flat-mounted preparation of E11.5 hindbrains. Migration of FBM neurons is arrested in r5 and their exit points are disrupted (arrowhead in U vs arrowheads in V) (control: n = 4; Isl1hypo/KO mice: n = 3; number of embryos). (W,X) Whole-mount views of E11.5 Hb9::GFP mice. Axons of hypoglossal (XII) neurons and spinal cord MNs in Isl1hypo/KO mice are severely reduced or missing (arrowheads) (control: n = 4; Isl1hypo/KO mice: n = 3; number of embryos). (Y-BB) Flat-mount views of E11.5 Hb9::GFP hindbrains. The abducens neurons in r5 and SM somata are reduced and the interneuron-like longitudinal projections were found in the Isl1hypo/KO mice (arrows, BB) (control: n = 5; Isl1hypo/KO mice: n = 2; number of embryos). III, oculomotor; (V) trigeminal mandibular; VII, facial nerve; IX, glossopharyngeal; X, vagal; XI, spinal accessory; XII, hypoglossal nerve; FBMf, facial branchio motor neuron fibers; IEEf, inner ear efferent fibers. Scale bars: in (D), 500 μm for (A–D) in (L), 250 μm for (E–L) in (T), 500 μm for (Q–T) in (V), 200 μm for (U,V) in (X), 250 μm for (W,X) in (BB), 200 μm for (Y-BB).
