Generation of ADAMTS13-deficient mice. (A) Schematic diagrams of the wild-type and targeted Adamts13 alleles and the targeting vector. Exons are indicated as numbered boxes. The locations of PCR primers used in B are indicated by lower-case letters and arrows. The locations of selected restriction sites are indicated by upper-case letters (E, EcoRI; H, HindIII; and S, SpeI). (B) Genomic PCR demonstrating correct targeting of the Adamts13 gene. Lanes 1, 4, and 7: primers a + b; lanes 2, 5, and 8: primers c + d + e; and lanes 3, 6, and 9: primers f + g. A 240-bp band specific for the Neo insertion is seen only in Adamts13^+/– and Adamts13^–/– mice (lanes 4 and 7); a 280-bp band specific for the targeting vector is seen only in Adamts13^+/– and Adamts13^–/– mice (lanes 5 and 8); a 370-bp specific for the wild-type allele is seen only in Adamts13^+/+ and Adamts13^+/– mice (lanes 2 and 5); and a 400-bp band specific for deleted exon 6 is seen only in Adamts13^+/+ and Adamts13^+/– mice (lanes 3 and 6) and is not seen in Adamts13^–/– mice (lane 9). (C) RT-PCR of liver mRNA prepared from Adamts13^B/129+/+, Adamts13^B/129+/–, and Adamts13^B/129–/– mice. Primers specific for exons 1–6 of Adamts13 (upper panel) or vWF (lower panel) were used. Adamts13 exons 1–6 were readily detected in mRNA from Adamts13^B/129+/+ and Adamts13^B/129+/– mice but were absent in mRNA from Adamts13^B/129–/– mice.