Identification, molecular cloning, and developmental gene expression of a 34 KD protein produced by bovine extraembryonic during early pregnancy

Collagen is by far the most prevalent vertebrate protein as it constitutes approximately 30% of all proteins present in mammals. In fibrous or solid forms, the various collagens junction primarily as the principal supporting elements in a wide variety of connective tissues. Nevertheless, more recent researches strongly suggesting that collagen may play active roles in developmental processes, cell attachment, differentiation, growth and migration. In this dissertation, a major placental protein, designated 2B₉, was identified as carboxyl-terminal propeptide of bovine collagen III during early embryonic development. cDNA clone of this protein was obtained and characterized. Developmental gene expression of this protein was studied in both bovine and ovine extraembryonic tissues. Results indicated that cDNA clone of 2B₉ protein contained the entire 245 amino acid coding region for the carboxyl-terminal propeptide of bovine collagen III as well as the carboxyl telopeptide region and 3' untranslated region extension. On set of expression of bovine procollagen III mRNA was paralleled by the protein production, suggesting procollagen III regulation might be under transcriptional control. Coincidental expression of the procollagen III gene with development of bovine chorioallantois suggested an important role for collagen III in the early embryonic development. Bovine procollagen III gene contained multiple polyadenylation signals, differential usage of these signals might be a characteristic of collagen genes during development.