Isolation and characterization of collagen messenger RNA*

Chick embryo collagen-synthesizing polysomes were isolated by differential centrifugation. RNA extracted from these particles was chromatographed in oligo(dT)-cellulose solumns and the mRNA thus obtained characterized as collagen mRNA by its electrophoetical mobility in acrylamide gels (equivalent to 1.05 x 10-6 daltons) and its effect upon a cell-free system derived from Krebs ascites tumor cells. The incorporation of 3H-proline was markedly dependent upon rabbit reticulocyte initiation factors and inhibited by initiation inhibitors such as aurintricaboxilate and pyrocatechol violet. The incorporation product was characterized as collagen by its lack of tryptophan, digestibility by purified bacterial collagenase, and by its co-chromatography with unlabled chick collagen in Sephadex G-200 and CM-cellulose columns.