IDENTIFICATION OF COLLAGEN MESSENGER-RNA

RNA isolated from calvaria of 16- to 18-day-old chick embryos, assayed in rabbit reticulocyte lysates, programs the synthesis of a collagenase-sensitive protein with the molecular weight of collagen pro-.alpha.-chains. When RNA labeled with [3H]uridine for 2 h and chased for 1 or 2 h was electrophoresed on aqueous polyacrylamide gels, most of the radioactivity not in 28S or 18S rRNA migrated with an apparent MW of about 1,800,000. After oligo(dT)-cellulose chromotography and analysis in 99% formamide gels, this nonribosomal, rapidly labeled calvaria RNA species migrates at 28S-30S and thus has a MW of at least 1,600,000. Both the ability to program the synthesis of collagenase-sensitive protein in reticulocyte lysates and the presence of a single prominent rapidly labeled 30S peak in acrylamide gels strongly support the deduction that there is only 1 major mRNA species in calvaria and that this species is collagen messenger RNA.