title: Translation of embryonic-chick tendon procollagen messenger ribonucleic acid in two cell-free protein-synthesizing systems.
abstract: Embryonic-chick tendon poly(A)-containing RNA was translated in the wheat-germ and mRNA-dependent rabbit reticulocyte-lysate systems. The ability of each system to synthesize polypeptides similar to pro-alpha chains of collagen was tested on the bases of electrophoretic mobility and susceptibility to highly purified bacterial collagenase. Very small amounts of polypeptides in the size range of pro-alpha chains were synthesized in the wheat-germ system, whereas efficient synthesis of two polypeptides similar to pro-alpha1 and pro-alpha2 chains was achieved in the reticulocyte lysate. The collagenous nature of the major high-molecular-weight products synthesized was demonstrated by their susceptibility to collagenase and ability to act as a substrate for purified collagen proline hydroxylase. Determinations of the relative amounts of these translation products suggest that the 2:1 ratio of pro-alpha1 and pro-alpha2 chains found in type I procollagen is reflected in proportional amounts of translatable mRNA for pro-alpha1 and pro-alpha2 chains. Comparisons of the electrophoretic mobilities of hydroxylated and unhydroxylated reticulocyte-lysate translation products were made with appropriate standards of hydroxylated and unhydroxylated procollagen polypeptides. The results suggest that, in common with a number of secreted proteins, procollagen is synthesized as pre-pro molecules consistent with the ;Signal Hypothesis'.
mesh_terms: D000818:Animals; D002474:Cell-Free System; D002642:Chick Embryo; D066298:In Vitro Techniques; D010779:Photofluorography; D011347:Procollagen / Q000096:biosynthesis*; D011393:Procollagen-Proline Dioxygenase / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism; D012639:Seeds / Q000378:metabolism; D013710:Tendons / Q000196:embryology / Q000378:metabolism; D014908:Triticum / Q000378:metabolism
chemical_list: D011347:Procollagen; D012333:RNA, Messenger; D011393:Procollagen-Proline Dioxygenase