Wnt5a and PCP/Neurogenesis Figure 1. Temporal and spatial expression of Wnt5a in the mouse. (A) In situ hybridization for Wnt5a on coronal midbrain sections of E9.5– E13.5 CD1 mice shows a dynamic regulation of Wnt5a expression domains throughout development in both rostrocaudal distribution and developmental stages. Schemes with sagittal sections of the brain and dashed lines show the levels at which rostral (r) or caudal (c) expression analysis was performed. The expression of Wnt5a occupies the entire neuroepithelium of the ventral midbrain at E9.5 and 10.5, and becomes progressively restricted to the floor plate and basal plate ventricular zone from E11.5–E13.5, extending to the marginal zone at caudal levels (Scale bars at E9.5 = 100 mm, at E10.5 and E11.5 = 200 mm, at E12.5 and E13.5 = 175 mm). (B) At E12.5, the expression of Wnt5a comprises the FP extending from the ventricular zone through the intermediate zone and into the marginal zone, overlapping with NR4A2+ and TH+ cells. This extension into the marginal zone is most pronounced in the caudal midbrain. (C) The expression of Wnt5a is down-regulated by E18.5, where it still overlaps with TH+ cells, but 8 weeks after birth, at P56, this overlap is lost as seen in sagittal and coronal sections. (Scale bars in brightfield E18.5, coronal P56 and darkfield sagital p56 = 500 mm, scale bar in brightfield sagital P56 = 2.5 mm). Abbreviations: r = rostral, c = caudal, F = forebrain, D = diencephalon, M = midbrain, H = hindbrain. doi:10.1371/journal.pone.0003517.g001 PLoS ONE | www.plosone.org 3 October 2008 | Volume 3 | Issue 10 | e3517