Modulation of soluble HJV production in differentiated murine myoblasts. (A) Morphologic differentiation of murine myoblasts (top panel) to myotubes (bottom panel) after incubation in differentiation medium for 72 hours. Phase-contrast microscopy was performed with a Leica DM IRB microscope, 20×/0.30 NA objective, and images were acquired with a Leica DC 300 FX camera and Leica IM50 software (Leica Microsystems, Wetzlar, Germany). (B) After incubation in serum-free media, media and total lysates from undifferentiated (U) and differentiated (D) cells were loaded onto a 10% SDS-PAGE, blotted, and analyzed by anti-HJV, anti-furin, anti–HIF-1α, and anti–myosin heavy chain (MyHC). α-Tubulin was used to verify equal loading.