The proposed plan of study is designed to gain insights into the structure, function and regulation of tissue-specific class I molecules. We will investigate a new class I molecule that is found in F1 (Qa-2 a(+) Qa-2b(-)F1 animals but not found in either parent. This study will provide insights into nature of the Qa-2b(-) null allele and may allow an understanding of the underlying mechanisms involved in the regulation of Qa-2 expression in normal cells and its inappropriate expression in transformed cells. Studies on the biosynthesis/turnover of Qa-2 will be initiated. This basic information will allow us to identify the thymus cell subpopulations which synthesize Qa-2 and may allow us to define conditions which induce Qa-2 synthesis in Qa-2(-) thymus cells as a consequence of functional maturation. In addition the development of a Qa-2 expression/induction system will allow for future studies aim at understanding at the nucleic acid, and protein levels mechanism regulating Qa-2 expression. A bone marrow-specific class I species has been described. Studies will be confined to genetically mapping the product to a specific H-2, Qa or TL locus. Since this molecule may serve to distinguish a specific bone marrow cell functional subpopulation attempts will be made to identify the cells expressing this molecule.
