A mouse Cd4 minigene consisting of a SacI-SpeI fragment from intron 1, the upstream enhancer, promoter (0.5 kb), 5' UTR-containing exon 1, start and end of intron 1 (internal deletion of PstI-HindIII fragment) and the 5' UTR part of the start codon-containing exon 2, was linked to the human CD2 cDNA sequence, followed by SV40 poly(A) signal sequence. (J:18902)