TCR-BETA AND TCR-ALPHA GENE ENHANCERS CONFER TISSUE-SPECIFICITY AND STAGE-SPECIFICITY ON V(D)J RECOMBINATION EVENTS

We describe transgenic mice carrying germline variable gene segments a ssociated with either the T cell receptor (TCR) beta or alpha gene enh ancers (Ebeta or Ealpha). Transgenic constructs underwent high rates o f site-specific rearrangements predominantly in T cells from independe nt mice. Rearrangements of the Ebeta-containing transgenes began at di fferent stages of T cell differentiation in embryonic and adult thymus than did the Ealpha-containing ones, with a pattern superimposable up on the patterns of TCRbeta or TCRalpha gene expression, respectively. We demonstrate that sequences within the TCRbeta and TCRalpha gene enh ancers confer tissue- and stage-specificity upon the V(D)J recombinati on events affecting adjacent gene segments. The patterns of transgene expression also gave information on developmental events and lineage r elationships (gammadelta versus alphabeta) during T cell development.