"Embryonic" collagen (type I trimer) alpha 1-chains are genetically distinct from type I collagens alpha 1-chains

Our laboratory has previously demonstrated that cell lines derived from early embryonic mouse sources produce procollagen and collagen and suggested that this material represents a new genetic type of collagen. Evidence was presented using carboxymethyl cellulose chromatography, analytical isoelectric focusing, cyanogen bromide peptide analysis, amino acid analysis, and carbohydrate analysis which demonstrated that this "embryonic" collagen consisted of three identical alpha-chains, distinctly different from types I, II and III and IV collagen and thus probably represented a new type of collagen. Further evidence is presented using Staphylococcus aureus V-8 protease generated peptide maps and immunological studies using antisera prepared against "embryonic" collagen and procollagen. These data clearly demonstrated that "embryonic" collagen is clearly distinct from type I alpha-chains and represents a unique genetic species of collagen.