The D^d-ζ construct. (A) A chimeric protein containing the extracellular (EC) and transmembrane (TM) portions of the mouse H-2 D^d molecule associated with the intracellular (IC) portion of the mouse ζ chain. (B) A schematic illustrating the cloning of the D^d-ζ construct into the human CD2 promoter/enhancer cassette p29Δ2(Sal–). The D^d-ζ chimera was partially digested with BamH1, such that only the poly A tail was removed. An EcoR1-SalI fragment was removed from p29Δ2(Sal–) and replaced with the D^d-ζ chimera by blunt-end ligation.