Molecular markers support a role for Cx43.4 in KV function. In situ hybridizations are used to probe for expression of genes in the L–R signaling cascade. (A–D) Twelve-somite Cx43.4 morphant embryos probed for spaw expression (arrowheads, throughout) show left, right, bilateral, and absent expression, respectively. spaw expression data are quantified (E) at 12 somites and (F) at 20 somites. Twenty-somite embryos probed with lefty1 show (G) normal expression in wild-type and (H) reversed expression in a DFC-targeted Cx43.4 knockdown embryo. (I) lefty1 data are summarized. (J) Twenty-somite embryos probed with lefty2 show a (K) reversal in the developing heart field of the Cx43.4 morphant. (L) Quantification of lefty2 expression was compiled from three independent experiments. Graphs in (E, F, I, L) represent means ± SEM from three independent experiments.
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