This construct was used to introduce the corresponding human FOP mutation R206H and
the constitutive active variant of the receptor Q207D by Site - Directed Mutagenesis (QuikChange, Stratagene) using the following primer pairs (with lower - case letters indicating the nucleotides changed relative to wild - type Acvr1 sequence): R206H - chAcvr1 - fwd, 5 ′ - GCAAAGAACAGTGGCTCaCCAGATCACGCTTGTGG - 3 ′ and R206H - chAcvr1 - rev, 5 ′ - CCACAAGCGTGATCTGGtGAGCCACTGTTCTTTGC - 3 ′; chAcvr1 - ca - Q207D - fwd, 5 ′ - GCAAAGAACAGTGGCTCGCgAcATCACGCTTGTGGAGTG - 3 ′ and chAcvr1 - ca - Q207D - rev, 5 ′ - CACTCCACAAGCGTGATgTcGCGAGCCACTGTTCTTTGC - 3 ′).