The Cys-His-Gly triplet within the WNT motif is essential for Wnt16 function in vivo.

WNTs are critical to many developmental and disease processes. They are post-translationally acylated at a serine within a highly conserved sequence termed the "WNT motif". Changes in individual amino acids in the WNT motif reduce but do not eliminate WNT function. However, the role of a highly conserved triplet of residues (Cys-His-Gly) upstream of the serine has yet to be examined. We show that an in-frame deletion of the Cys-His-Gly triplet in zebrafish Wnt16 likely functions as a null mutation. These findings highlight the utility of using small in-frame indels that target conserved amino acid regions to modulate protein function.