Distinct photoreceptor outcomes in Nrlb2/b2 and Nrl−/− mice. A, Western blot analysis of cone opsins and rhodopsin in retina from 6-week-old mice of the indicated Nrl genotypes. Thrb2−/− lane, Sample from TRβ2-deficient mice as a negative control for M opsin. B, Western blot analysis of cone opsins and TRβ2 in retina from P14 mice of the indicated Nrl genotypes. The initial induction of M opsin is pronounced in Nrlb2/b2 mice at this juvenile age. C, Quantitative PCR analysis of M opsin, S opsin, and TRβ2 mRNA levels in retina of mice of the indicated Nrl genotypes at P17.