Fusion induces human myosin heavy chain expression. RT-PCR of the cultured cells shows elevated expressions of human skeletal myosin heavy chain IIa (MyH-2a) in cocultures of stromal cells and C2C12 cells. Lane 1 is from human skeletal muscle cells and serves as a positive control; lane 2, C2C12 cells alone; lane 3, human MSCs alone; lane 4, coculture of MSCs and C2C12; lane 5, human LTCs alone; and lane 6, coculture of human LTCs and C2C12. Actin was used as a loading control.