Towards the Structure and Function of Xiphophorus LARP6 RRM

Fibrosis is the formation of scar tissue in an organ or tissue that can lead to detrimental effects on the body. A key hallmark of fibrosis is the excess deposition of collagen at a wound site. Type I collagen is the most abundant protein found at wound sites and controlling the biosynthesis of type I collagen could provide a new therapy for treating fibrosis. The LARP6 protein is known to bind type I collagen mRNA, utilizing the LAM and RRM domains. After transcription, LARP6 shuttles type I collagen mRNA from the nucleus to the rough ER where it is translated and folded into a triple helix. Shutting down this transport by LARP6 and impeding the synthesis of collagen could provide a novel treatment of fibrosis. Understanding the structural details of how LARP6 binds type I collagen mRNA is the main objective. We used E. coli recombinant expression of the LARP6 RRM domain to produce isotopically enriched protein for Nuclear Magnetic Resonance (NMR) structural studies. Expression was optimized in order to produce soluble protein at high yield. NMR will be used to understand the structure, RNA binding mode, and how LARP6 binds to type I collagen mRNA