RNA biosynthesis in the chick embryo during development and its relation to collagen synthesis

A study of RNA synthesis in the legs and wings of chick embryos suggests synthesis of specific RNA's as a function of development. An increase in RNA at day 10 was followed by an increase in collagen synthesis. That RNA had a sedimentation coefficient of 23S and several of the characteristics of mRNA. Thus it appeared to contain a poly A sequence since it was retained on poly U coated-filters, it was not methylated, and its synthesis was not inhibited by low doses of actinomycin D. That RNA was found able to direct protein synthesis in a cell-free system derived from wheat germ. In the presence of that RNA, a small amount of protein was synthesized that migrated in acrylamide gel electrophoresis with the alpha chains of collagen and was partially digested by bacterial collagenase.