Arkadia (ARK)

The mouse counterpart of this gene (Rnf111/arkadia) has been shown to genetically interact with the transforming growth factor (TGF) beta-like factor Nodal, and act as a modulator of the nodal signaling cascade, which is essential for the induction of mesoderm during embryonic development.The human Arkadia amino acid sequence is 90%, 83%, and 73% identical to that of mouse, chick, and Xenopus, respectively. The Arkadia protein possesses a RING-H2 finger motif at its carboxy-terminal end. It also has 2 putative nuclear localization signals and low-complexity amino acid repeats. Arkadia is essential for HNF3B expression in the anterior primitive streak. Analysis with chimeras, however, shows that Arkadia functions within extraembryonic tissues, revealing that these are required to induce the node.