Generation and characterization of mouse strains. A, A schematic depicting the establishment of EndoJAM-AKD and HematoJAM-AKO mice used in infection experiments. Exon 1 of junctional adhesion molecule-A (JAM-A) is flanked by loxP sites in JAM-A f/f mice. Cre recombinase expression in tissue-specific Cre tg mice is driven by Tek (endothelial) or Vav1 promoter and enhancer sequences from an inserted transgene. Crosses between JAM-A f/f and tissue-specific Cre mice generate mice in which exon 1 of JAM-A is excised in tissues where Cre is expressed. Arrows indicate primer-binding sites for JAM-A primers (J1, J2), JAM-A f/f primers (F1, F2), Tek-Cre primers (TC1, TC2), and Vav-Cre primers (VC1, VC2). B, Mice that express JAM-A only within the hematopoietic cell compartment (HematoJAM-A mice) were obtained by establishing tg mice expressing a transgene in which JAM-A expression is driven by Vav1 promoter and enhancer sequences. JAM-A expression in other tissues was abolished by breeding the tg mice with JAM-AKO mice. Arrows indicate primer-binding sites for Vav-JAM primers (VJ1, VJ2). C and D, JAM-A expression was assessed in 6- to 8-week-old mice by genomic DNA polymerase chain reaction (PCR) and flow cytometry. C, Agarose gels displaying bands corresponding to regions of genomic DNA amplified in genotyping PCR reactions. Bands from the following reactions are shown for each mouse strain: JAM-A f/f, Tek-Cre, Vav-Cre, Vav-JAM, and JAM-AKO. D, Hematopoietic cells were collected from blood and spleens, and endothelial cells were cultured from lungs. JAM-A expression was quantified using flow cytometry. Flow cytometric profiles of endothelial and hematopoietic cells (peripheral blood granulocytes and macrophages) from each mouse strain. Abbreviations: CRE, Cre recombinase; E, enhancer; EKD, EndoJAM-AKD; HJ, HematoJAM-A; HKO, HematoJAM-AKO; JAM, JAM-A coding sequence; KO, JAM-AKO; PRO, promoter; US, unstained; Vav, Vav promoter; WT, wild-type (JAM-A f/f).