Fig. 2. MLC2v and MLC2a are expressed in a normal manner and mark the developing outflow tract in both wild-type and Rxra^–/– embryos. Adjacent transverse sections of E13.5 wild-type (A-C) and Rxra^–/– (D-F) embryonic hearts. Both MLC2v (B,E) and MLC2a (C,F) are expressed in their respective chambers in both wild-type and mutant embryos. Note that MLC2a is also expressed in a subset of OFT myocardium (C,F, arrowheads) and that this expression pattern is identical in both wild-type and mutant embryos.