Conditional deletion of the “floxed” GIMAP1 allele with the use of the hCD2-iCre transgene. (A) Gene targeting strategy. The targeting vector introduced LoxP sites (black arrowheads) to flank GIMAP1 exon 3. A neomycin resistance cassette flanked by FRT sites (gray arrowheads) was located downstream of the LoxP sites. Southern probes used to determine correct targeting of ES cells after SpeI and BamHI DNA digests are indicated. (B) PCR analysis to detect the floxed and wild-type alleles of GIMAP1 in genomic lung (L) and thymus (T) DNA. (C) Western blot analysis of GIMAP1 and GIMAP5 expression in thymocytes and lymph node cells.