Rearranged TCR alpha and beta genes containing endogenous promoter and enhancer sequences were coinjected into the micronucleus of 1 cell embryos. Both constructs are specific for the carboxyterminal fragment of pigeon cytochrome c and the Ek molecule. The alpha-chain of this transgenic TCR differs by one amino acid (an alanine instead of a threonine at position 99) to the alpha chain of the transgenic TCR expressed in Tg(TcraTcrbAD10)1Hed transgenic mice. (J:85777)