T-cell receptor gamma delta and gamma transgenic mice suggest a role of a gamma gene silencer in the generation of alpha beta T cells.

Abstract
A T lymphocyte expresses on its surface one of two types of antigen receptor, T-cell receptor .alpha..beta. or T-cell receptor .gamma..delta., encoded by a pair of somatically rearranged .alpha. and .beta. or .gamma. and .delta. genes. It has been suggested that .alpha..beta. T cells are generated only from precursor T cells that failed to rearrange .gamma. and .delta. genes in a functional form. However, we found that transgenic mice constructed with functionally rearranged .gamma. and .delta. genes produce a normal number of .alpha..beta. T cells. The transgene .gamma. present in these .alpha..beta. T cells is repressed apparently through an associated cis DNA element (silencer). We propose that some T-cell precursors are committed to generate .alpha..beta. T cells independent of the rearrangement status of their .gamma. gene and that this commitment involves activation of a factor(s) that interacts with the .gamma. gene-associated silencer.