The beta3A subunit is present at normal levels in other mouse HPS mutants. Platelet extracts (40 μg protein) were Western blotted and probed with antibody to beta3A. The C57BL/6J strain is the control strain for congenic mutants pearl (pe/pe), ruby eye (ru/ru), gunmetal (gm/gm), and light ear (le/le). The muted (mu/mu) and sandy (sdy/sdy) mutants are maintained on other inbred backgrounds and therefore the appropriate genetic control strains are mu/+ andsdy/+, respectively. Blots were reprobed with an antibody to mouse actin (below) as a loading control.