Figure 4. ESRRa regulates expression of genes essential for cartilage development.

(A–N) Embryos at 1-cell stage were injected with either MOctrl or MOesrra, raised and analysed at the indicated stages for expression of sox9a, sox9b,sox5, sox6 and col2a1 by in situ hybridization. At 2- and 3 dpf, expression of sox9 (A–H) and col2a1 (M and N) is specifically decreased in the branchial arches in MOesrra-injected embryos, although it remains comparable in other expression domains as compared to that in control. Expression of sox5 and sox6 at 2 dpf is also substantially decreased in MOesrra-injected embryos as compared to that in control (I–L). White arrows or bars indicate branchial arches and insets shown are magnified views of the branchial regions.