CARDIAC MUSCLE CELL DIFFERENTIATION IN VITRO FROM A CHARACTERISTIC CELL LINE ISOLATED FROM MOUSE TERATOCARCINOMA

A characteristic in vitro cell line, SEBIII, was isolated from the mouse teratocarcinoma OTT6050. The SEBIII line, which maintains the structure of the embryoid body, grows rapidly in suspension culture. The chromosome number is near diploid. SEBIII cells, which were transferred to the peritoneal cavity of 129/Sv strain mice and left for one week, differentiated into several tissues in the subsequent in vitro culture. Of the tissues differentiated, the most dominant was the spontaneously pulsating muscle cells. Electron microscopic observations of these muscle cells revealed the presence of myofilaments with Z bands and intercalated disks. The nature of the factor(s) which induce the differentiation of SEBIII EB into cardiac muscle cells is discussed.