Extended Data Fig. 9: RARB and RXRB are expressed in a moderate anterior-to-posterior gradient in the developing neocortex.

a, Quantitative PCR analysis of Rara, b, g and Rxra, b, g transcripts in the anterior and posterior half of mouse cortex at PD 0. Two-tailed Student’s t-test: ***P = 4e-4, 1e-4; N = 3 per condition; Errors bars: S.E.M. b, Quantitative PCR analysis of Rarb and Rxrg transcripts in four sections dissected out of the cortical plate in anterior-posterior direction. Both genes showed an anterior-posterior gradient in expression level. Two-tailed Student’s t-test; N = 3 per condition; Errors bars: S.E.M. c, Expression of Rarb and Rxrg in mouse (PD 0), macaque (PCD 140) and human (PCW 21) brains by in situ hybridization. Higher magnification images of the regions of anterior cortex. Rarb and Rxrg transcripts are upregulated in the anterior part of the cortex in all three. Scale bars, 200 μm (mouse); 2 mm (human); 500 μm (human, higher magnification). N = 2 for human and macaque, N = 3 for mouse. d, Strategies for the generation of Rarb and Rxrg KO mice using CRISPR-Cas9 technique⁴¹.