The structure, assembly, and regulation of expression of the T cell antigen receptor are the goals of this group. The T cell antigen receptor is a seven chain multicomponent receptor complex responsible for the initiation and specificity of the immune response. The most recently described chains of the T cell receptor are the two zeta chains which exist as a homodimer. The genes for the both murine and human zeta have been cloned, sequenced, and expressed. This has allowed us to complete the picture of the primary structure of all the components of this receptor complex. The gene has been isolated, characterized in terms of its 5' flanking region, its transcription initiation sites, and intron exon structure. The human gene has been localized to chromosome 1. The isolation of variants and mutants of T cells that lack a variety of the chains of the T cell receptor have allowed us to model the allowable subunit interactions when only some of the chains of the receptor are available. This has enabled us to come up with a nearest-neighbor model for the receptor. We have demonstrated that the zeta chain is most likely under the control of negative transacting regulatory elements. Studies on the assembly of the seven chain receptor complex has led to our proposal of the idea of architectural editing of newly synthesized membrane proteins. According to this model, quaternary structure of membrane complexes are recognized by the cell as either being correct or incorrect. Once this recognition occurs, the fate of those complexes within the cell is then determined. In this way only "correct" complexes are expressed on cell surface. In determining possible fates of incorrectly assembled membrane proteins, we have discovered a new pathway within the cell which we have termed the ER degradative pathway.