Fig. 4. Loss of Ngn2 results in a decrease in number of Nurr1⁺ cells at E11.5. (A-D) No change in BrdU incorporation (A,B) or in Sox2⁺/Ki67⁺ double labeled cells (C,D) was found in Ngn2^–/– mice compared with wild types at E11.5. (E-G) A simultaneous decrease in number of Nurr1⁺ cells was detected in the intermediate and marginal zones (E, n=5; ^**P<0.01, Student's t-test with Welch's correction). (H,I) GFP⁺/Nurr1⁺ cells were also missing directly under the ventral midline in Ngn2^Gfp/Gfp embryos. (J-M) The expression of Hes5 (J,K) and Dll1 (L,M), two markers of proneural activity, was also reduced in the ventricular zone. Scale bar: 100 µm.