This transgene was generated by coinjection of two transgene constructs, one expressing a constitutively active mutant mouse aryl hydrocarbon receptor and the other expressing green fluorescent protein, both under control of the T-cell lineage-specific human CD2 promoter. It was estimated by Southern blot analysis that Line A has two copies of the cointegrated transgenes. Transgene expression was detected by RT-PCR in thymus, spleen and lung and to a very minor extent in kidney. Flow cytometry analysis of GFP expression revealed a broader peak of fluorescence for thymocytes than for splenocytes; splenic Cd4+ and CD8+ T cells express GFP, while splenic B cells do not. (J:97720)