Changes in the methylation pattern of the TCR zeta-chain gene correlate with its expression in T cells and developing thymocytes.

The tight regulation of T-cell gene expression during thymic ontogeny is essential to the development of a normal immune system. One set of developmentally regulated genes encodes the multicomponent T-cell antigen receptor (TCR). The zeta chain, a component of the TCR, has been shown to play important roles in signal transduction from antigen binding to T-cell activation and in transport of the TCR complex to the cell surface. In this study, we examine the regulation of zeta gene expression in murine T-cell hybridomas. In these cells, zeta expression is correlated with complex, but predictable, changes in the pattern of cytosine methylation of its gene. Some of these structural changes are identical to those observed in murine fetal thymocytes and correlate with the rapid alteration of zeta message seen in the thymus between days 15 and 18 of gestation.