A mouse BAC clone Containing Rag1 and Rag2 was obtained from Research Genetics. An EGFP cDNA was inserted in this clone at the start codon of Rag2 by homologous recombination. A termination codon is present at the end of the EGFP sequence. 3 lines were generated and found to have identical GFP expression. This is a representative transgene for all 3 lines. (J:56779)