Repertoire of the human T cell gamma genes: high frequency of nonfunctional transcripts in thymus and mature T cells

Abstract

To further understand the structural diversity and function of the human T cell‐specific γ gene, 20 human γ gene cDNA from both thymocyte and peripheral blood T lymphocyte libraries were sequenced and analyzed. Evidence of greater germ‐line multiplicity and more extensive use of junctional flexibility, N‐region diversity and perhaps Dγ gene segment incorporation was observed. In spite of the larger γ gene repertoire found in humans compared to mice, the potential of the human γ gene message to encode a functional product appears to be severely limited. In addition to the extremely low levels of γ gene expression observed, each of the 20 γ gene cDNA exhibit some form of deleterious mutation defect. This is in sharp contrast to the finding that human and mouse T cell antigen receptor α and β messages isolated from various sources have functional coding potential in most cases. Thus, the role of the human T cell γ gene becomes even more uncertain than before. Copyright © 1987 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim