The function and biosynthesis of low molecular weight protein (8,700 daltons) (LMW protein) that has been isolated from bovine lingual epithelium will be studied in detail. This protein has been purified and characterized previously and has been shown to occur in stratified squamous epithelium and no other kind of epithelia by peroxidase coupled immunohistochemical techniques. The function of LMW protein will be studied by examining its interaction with keratin filaments in in vitro experiments. These experiments will employ techniques such as turbidometry, sedimentation analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and light and electron microscopic immunochemical technqiues. Furthermore, biosynthesis of LMW protein will be studied in cells cultured from oral epithelium or in explants of oral epithelium. Efforts will be directed at determining whether LMW protein is synthesized as a higher molecular weight precursor that is processed intracellularly. I also plan to ascertain whether LMW protein synthesis occurs on free or cytoskeletal or membrane-bound polyribosomes. These experiments will employ the use of radioisotopically labeled amino acid precursors, cell fractionation, SDS-PAGE, fluorography, and immunoblotting. The long range goal is to gain an understanding of the normal process of cellular differentiation and maturation in oral mucosa. The epithelia of the oral mucosa exhibits a wide range of variation and specialization, the basic details of which are essentially unknown. Clinical conditions such as gingival hyperplasia may be understood in basic terms of the cell biology of the keratinizing cell as a result of the knowledge gained in this proposal.
