Targeted disruption of the Hjv gene. (A) Schematic representation of the mouse wild-type Hjv genomic sequence (+), LoxP-flanked allele with FRT-flanked Neo sequence (fl), and conditional knock out (cko) alleles. Positions of sequences coding for features of the protein are indicated as follows: (*) indicates the Tmprss6 cleavage site²⁸  and (#) the Furin cleavage site.^24,25  (B) Hjv mRNA relative expression in liver (L), heart (H), and skeletal muscle (SK) by quantitative RT-PCR. fl/fl indicates mice with the homozygous fl allele (n = 4); sk/sk, mice with the homozygous cko allele in skeletal muscle (n = 4). Quantitative PCR primers of Hjv were qF, the forward primer in exon 3, and qR, the reverse primer in exon 4. Rpl19 was used as an internal control. The Hjv expression level in liver from Hjv fl/fl mice was assigned as 1. Error bars represent SD.