Antagonistic signaling by Caronte, a novel Cerberus-related gene, establishes left-right asymmetric gene expression

Left-right asymmetry is initiated during chick embryogenesis in small domai ns near Hensen's node. Subsequently, broad asymmetric gene expression domai ns are established in the lateral plate mesoderm, ultimately determining th e directionality of morphogenetic events. The transfer of asymmetric inform ation from the node to the lateral plate is mediated by Caronte (Car), a na vel member of the Cerberus/Dan gene family, which induces targets by antago nizing symmetrically expressed BMP signals. In addition, BMP antagonism by Car induces asymmetric expression of Lefty in the midline, preventing sprea d of left-sided signals to the contralateral side.