Figure 1.

Creation of X4T transgenic mice. (A) Schematic representation of the pTRIP-X4 lentiviral vector. Restriction sites: E, EcoNI; A, AvaII. Filled circle, central DNA flap; filled box, X4 Orf. UbiC, human Ubiquitin C promoter. (B) Schematic representation of pTRIP-X4 provirus integrated in the genome of the X4T transgenic mouse line selected for this study. *, the positions of these sites are specific to the integration site. (C) Southern blot analysis of tail DNA shows a single integration of the transgene in the genome of X4T mice. EcoNI–AvaII–digested DNA from X4T-positive and control littermate X4T-negative mice was hybridized with the 5′ flanking probe A, the internal probe B, and the 3′ flanking probe C as indicated in A. Refer to B for expected sizes of bands. (D) Analysis of X4T expression in transgenic mice. Western blot analysis of X4T (top) and endogenous X4 (bottom) expression in purified splenic mature B cells and thymocytes of X4T mice and control X4T-negative mice (all on a wild-type background) revealed by anti-X4 antibody.