Patent ID: 7063961

Claim:
A nucleic acid molecule encoding a heregulin variant having an amino acid sequence not found in nature and the ability to bind an ErbB receptor, wherein said variant comprises a methionine residue in place of amino acid residues corresponding to residue numbers 228 to 231 of native human heregulin-β1 (SEQ ID NO: 93) numbered from the N-terminus and said heregulin variant comprises a portion that is at least 70% identical to the portion from about residue 175 to about residue 230 of native human heregulin-β1 (SEQ ID NO: 93), said heregulin variant having a greater specificity for the ErbB-4 receptor, relative to the ErbB-3 receptor, than a heregulin that differs from the heregulin variant only in that the heregulin comprises said amino acid residues corresponding to residue numbers 228 to 231 in place of said methiomne.