Spatial and temporal expression of Neurog2 in the developing mouse olfactory bulb. (A-C) Overview of the distribution of Ngn2GFP expression at E13.5 and E17.5 and postnatal day 0 in the cortex, SVZ and OB. Rostral is to the right of the image. (D-G) Co-localization of Neurog2 with Pax6, Tbr2, Tbr1 and Dlx2 at E13.5. Note the high co-localization between Neurog2, Pax6 and Tbr2, and the minor co-localization between Neurog2 and Tbr1. Note that Neurog2 and Dlx2 were observed in different compartments of the developing OB, with Dlx2-positive cells located more ventrally and caudally than Neurog2-positive cells. In the region of overlap, although rare Neurog2+ cells expressed low levels of Dlx2, no significant co-localization could be observed. (H-K) Co-localization of Neurog2+/GFP with Pax6, Tbr2, Tbr1 and Neurog2 at E13.5. Little co-localization is seen between Neurog2+/GFP and Pax6; however, high co-expression of Neurog2+/GFP and Tbr2 and Tbr1 reveals that these markers are expressed in the same population of cells. Inserts show a higher magnification of the region surrounded by a dotted box. All photomicrographs in (D-K) show the same orientation as (A), with the VZ visible on the left and the OB parenchyma present on the right. Scale bar: 50 μm. CTX, cortex; Hipp, hippocampus; OB, olfactory bulb; VZ, ventricular zone.