Mussel adhesive plaque protein gene is a novel member of epidermal growth factor-like gene family.

A mussel (Mytilus galloprovincialis) cDNA encoding Mgfp2, a major component of the adhesive plaque that anchors mussels tightly to underwater surfaces was isolated. It encoded a protein mainly consisted of epidermal growth factor-like repeats, containing tyrosine residues that will be converted to 3,4-dihydroxyphenylalanine near C and N termini. Amino acid residues important for cell-cell interaction in other epidermal growth factor-like proteins were, however, not conserved in the structure of Mgfp2. RNA blot analysis on adult tissues showed foot-specific expression of this gene, while the analysis on developing larvae showed that the expression starts with formation of the foot. These results suggest that the function of Mgfp2 has been specialized to form the adhesive plaque.