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Expression of T-cell receptor alpha-chain genes in transgenic mice.

To examine the influences responsible for shaping the T-cell repertoire in vivo, we have introduced T-cell receptors of defined specificity into mice. In this report, we analyze transgenic mice carrying a T-cell receptor alpha-chain gene from a pigeon cytochrome c-reactive T-cell line. A variant of this construct, which has the immunoglobulin heavy-chain enhancer inserted into the JC intron, was also introduced into mice. Addition of the enhancer increased the steady-state level of transgene-encoded mRNA three- to fivefold in cultured T cells, leading to a two- to threefold increase in surface expression. In vivo, the difference between these two constructs was even more significant, increasing the number of transgene-positive cells from approximately 5 to 70% and the T-cell receptor surface density two- to threefold. Surprisingly, while surface expression of either type of transgene was limited to T cells, we found little tissue specificity with respect to transcription. In T cells expressing the alpha chain from the enhancer-containing construct, immunoprecipitation with a 2B4 alpha-specific monoclonal antibody revealed the expected disulfide-linked dimer. Costaining of these T cells with the 2B4 alpha-specific monoclonal antibody versus anti-CD3 indicated that expression of the transgene-encoded alpha chain precludes expression of endogenous alpha chains on the majority of cells; in contrast, 2B4 alpha-chain expression from the construct lacking the enhancer is inefficient at suppressing endogenous alpha-chain expression. In mice of the enhancer lineage, Southern blot analysis indicated suppression of endogenous alpha-chain rearrangements in T-cell populations, consistent with the observed allelic exclusion at the cellular level. Interestingly, newborn, but not adult, mice of this lineage also showed an increase in retention of unrearranged delta-chain loci in thymocyte DNA, presumably resulting from the suppression of alpha-chain rearrangements. This observation indicates that at least a fraction of alpha:beta-positive T cells have never attempted to produce functional delta rearrangements, thus suggesting that alpha:beta and gamma:delta T cells may be derived from different T-cell compartments (at least during the early phases of T-cell differentiation).

Pubmed ID: 3266655

Authors

  • Berg LJ
  • Fazekas de St Groth B
  • Ivars F
  • Goodnow CC
  • Gilfillan S
  • Garchon HJ
  • Davis MM

Journal

Molecular and cellular biology

Publication Data

December 26, 1988

Associated Grants

  • Agency: NCI NIH HHS, Id: 5T32 CA09302

Mesh Terms

  • Alleles
  • Animals
  • Blotting, Southern
  • Flow Cytometry
  • Genes
  • Macromolecular Substances
  • Mice
  • Mice, Inbred Strains
  • Mice, Transgenic
  • Pseudogenes
  • Receptors, Antigen, T-Cell
  • T-Lymphocytes
  • Transcription, Genetic
  • Transfection