DESCRIPTION (provided by applicant): We have a long-standing interest in how eukaryotic mRNA 3' ends are formed. Regulation of gene expression can be accomplished by regulating polyadenylation. We have combined this interest in polyadenylation with an interest in human collagen types I and II. Collagen plays a key role in normal cartilage development and skeletal morphogenesis. We have recently discovered and published that human COL1A2 polyadenylation is regulated by cis-acting elements present in the 3' untranslated region (3' UTR) of the COL1A2 mRNA, and that these elements influence the 3' end processing efficiency. Human COL1A1 and COL2A1 we have now discovered also contain these cis-acting elements. Based upon these findings, this project proposes to investigate the mechanism of regulation of polyadenylation of all these type I and II collagen pre-mRNAs. These investigations will expand our goal of better understanding the expression of collagens, and how mutations and abnormal gene expression regulation can initiate a disease state. Our specific aims for this project are: 1) To identify all the cis-acting elements involved in 3' polyadenylation site usage in the human collagen genes COL1A1, COL1A2, and COL2A1 and 2) To determine what trans-acting factor(s) bind to these cis-acting elements. First, we will identify cis-acting elements by deletion and site-directed mutagenesis, and examine their ability to affect polyadenylation efficiency both in vitro and in vivo. Second, protein factors that bind to these cis-acting signals will be explored and characterized. Determination of these protein factors will provide us with clues as to the functional significance of cis-acting auxiliary elements. Gaining an understanding of the RNA signals and protein factors involved in regulation of 3' end formation of these human collagen genes will help us to comprehend collagen gene expression regulation, which will in turn lead to novel insights into skeletal defects and other collagen-based diseases.