Figure 5. Klhl14 and Crim1 expression molecularly distinguishes and parcellates CSN_BC-lat versus CSN_TL during early development.

(A and B) In situ hybridization on serial coronal sections of a P4 brain showing Klhl14 (A) and Crim1 (B) expression.

(C) Overlay of inverted and pseudo-colored images from A and B. Klhl14 and Crim1 exhibit complementary expression.

(D–G’) There is no Klhl14 (D, E, and E’) or Crim1 (F, G, and G’) expression in the Fezf2 null cortex (E and E’), which lacks CSN, confirming that Klhl14+ and Crim1+ neurons are CSN. (D’, E’, F’, and G’) Magnified views of regions boxed in (D), (E), (F), and (G) respectively.

(H–J, L, and N) CSN_TL were retrogradely labeled (red in I, L, and N). (H) In situ hybridization showing that Klhl14 is excluded from CSN_TL (merged in J). (H’–J’) Caudal view of the same brain in (H)–(J) showing that Klhl14 is excluded from from CSN_TL even in caudal sensorimotor cortex.

(K–L’’) Crim1 (cyan in K) is expressed by almost all CSN_TL (magnified merged view in L, white; individual channels in L’ and L’’).

(M–N’’) Cry-mu (cyan in M), another CSN_medial-specific gene, is not expressed by all CSN_TL (magnified merged view in N, white; individual channels in N’ and N’’; arrowheads indicate labeled CSN_TL that do not express Cry-mu).

Scale bars, 500 μm.