In vivo expression of ΔCD98hc-β geo fusion protein. A. ΔCD98hc-β geo fusion protein is expressed in CD98hcΔ/+ mouse. Protein was extracted from CD98hcΔ/+ ES cells (PST080) or various tissue samples harvested from wild type (CD98hc+/+) and heterozygous mutant (CD98hcΔ/+) mice for Western blotting. Anti-β-galactosidase (β gal) antibody yields ~220 kD bands specific to CD98hcΔ/+ samples, while anti-CD98hc antibody yields ~80 kD bands in all samples. Note that the different mobility of the proteins from different tissues is likely due to different posttranslational modifications. The expression of integrin β1, which can interact with CB98hc, was detected in ES cells, intestine, and testis samples, but not in brain or kidney sample. The β actin was analyzed as a loading control. *, nonspecific bands. B. The expression pattern of ΔCD98hc-β geo fusion protein mimics that of CD98hc protein in CD98hcΔ/+ mouse. Kidney sections from CD98hc+/+ and CD98hcΔ/+ mice were immunostained with anti-CD98hc antibody or stained with X-gal to localize β-galactosidase activity that represents ΔCD98hc-β geo fusion protein. Note that distribution of immunoreactive CD98hc is the same as that of β-galactosidase activity in CD98hcΔ/+ kidneys. Lower right panel shows the magnified image of boxed area indicated in lower middle panel.