Cripto, FRL1, Cryptic Family 1 (CFC1)

Like other EGF-CFC family members, the deduced 224-amino acid human CRYPTIC protein, which is 22 residues longer than the mouse sequence, contains an N-terminal signal sequence, a variant EGF-like motif, a novel cysteine-rich domain called the CFC motif, and a C-terminal hydrophobic region. The EGF-like motif possesses the characteristic 6 cys residues, but the first 2 are adjacent, thus eliminating the A loop. Whole-mount in situ hybridization analysis of mouse embryos had shown an initial symmetry-breaking event in or around the node followed by propagation to the left lateral plate mesoderm where Nodal , Lefty2, and Pitx2 are expressed and regulate subsequent asymmetric morphogenesis . Cryptic mutant mice have defects in nearly all L-R asymmetric morphogenesis.