RUI: Assembly and Expression MHC Class II Chains in the Channel Catfish

East Carolina University, Greenville NC

Investigators

Abstract

The long-term goal of this research project is to characterize and define the specific processing events necessary for cell surface expression of MHC class II molecules in a teleost species. The immediate goal of this project is to determine the molecular events necessary for proper folding, assembly, and cell surface expression of class II heterodimers. In particular, the work seeks to determine the assembly of major histocompatibility complex (MHC) class II heterodimers in teleosts proceeds with assistance from the endoplasmic reticulum chaperone calnexin and the invariant chain. Preferential pairing of class II alpha and beta chains will be tested with transfection of the previously characterized encoding genes into catfish class II negative fibroblast cell lines. RNA and cell surface expression of class II genes and proteins will be examined. In other experiments, immunoprecipitations, immunoblots, flow cytometry, and immunofluorescence microscopy will be used to test the role of calnexin, calreticulin, and invariant chain in the processing and trafficking of class II molecules. The availability of catfish lymphoid, macrophage, and fibroblast cell lines, along with the previous characterization of two expressed MHC class II A and class II B loci, make the channel catfish a unique system among teleosts for the study of MHC class II assembly and cell surface expression.