Fig. 6.

Expression of an Nrp1 variant unable to bind Sema3A, or constitutive deletion of Sema3a, partially recapitulates the early Nrp1 deletion phenotype of M72-expressing fibers. (A-D) Dorsal and medial whole-mount views of X-Gal-stained Nrp1^+/sema;M72^+/lacZ (P33, A,B) and Sema3a^+/del;M72^lacZ/lacZ (P31, C,D) OBs. A, anterior; L, lateral; P, posterior; M, medial; D, dorsal; V, ventral. Scale bars: 1 mm in A for all dorsal OB views; 1 mm in B for all medial OB views. (E-H) Dorsal and medial whole-mount views of X-Gal-stained Nrp1^sema/sema;M72^lacZ/lacZ (P30, E,F) or Sema3a^del/del;M72^+/lacZ (P38, G,H) OBs showing a dorsalization of the glomeruli and an additional anterior glomerulus. (I,K) Comparison of the frequency of the specific phenotypes affecting M72 glomeruli assigned to the independent or linked/fused categories. The frequencies are compared between Nrp1^sema/sema, Sema3a^del/del and their respective controls (*P<0.001 for both, χ² test). In addition, the presence or absence of an anterior glomerulus in each OB (Nrp1^sema/sema, Sema3a^del/del and their respective controls) is indicated and their respective frequencies are compared (*P<0.001 for both, χ² test). (J,L) Mapping of M72 glomeruli (Nrp1^sema/sema, Sema3a^del/del and their respective control populations) on a medial representation of the OB. Glomeruli (from single OBs) linked to each other are connected by colored lines. A dot circled in black represents the mean position of glomeruli from each population. Ellipses represent the dispersion of each glomerular population. Data corresponding to control animals (Nrp1^+/sema, n=14 and Sema3a^+/del, n=14) are depicted in orange, and data from Nrp1^sema/sema (n=18) and Sema3a^del/del (n=8) mice are in magenta. Insets show close-ups from the glomerular targeting sites.