Multipotency of a bone marrow stromal cell line, TBR31-2, established fromts-SV40 T antigen gene transgenic mice

Bone marrow is believed to contain multipotential stromal stem cells which can differentiate into osteoblasts, chondrocytes, adipocytes, and myoblasts (Prockop, D. J. Science 276, 71-74, 1997). Therefore, characterization and identification of the stem-like cell within the stromal cells are importan t to understand bone marrow function in relation to the hematopoietic micro environment, and repair/regeneration of tissue defects. TBR31-2 cell, a bon e marrow stromal cell line established from bone marrow of transgenic mice harboring temperature-sensitive (ts) simian virus (SV) 40T-antigen gene for immortality, is induced toward both adipocytic and osteogenic cells under conditions of the inactivation of T-antigen (Okuyama, R., Yanai, N., Obinat a, M. Exp. Cell Res. 218, 424-429, 1995). In this work, using a semiquantit ative reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, mR NA expressions of tissue-specific differentiation markers for adipocyte (li poprotein lipase), osteoblast (fype I collagen and osteocalcin), chondrocyt e (type II and X collagen), and muscle cell (desmin) were examined during a long-term culture of the cell. In addition, histochemical studies showed t he appearance of adipocytic, osteoblastic, chondrocytic, and muscle cells d uring this long-term culture. Thus, TBR31-2, which has characteristics of a n undifferentiated cell, has the potential to express the multipotential ce ll lineages. These results indicated that a multipotential progenitor cell including potential to differentiate into a muscle cell and which is situat ed in the mesenchymal cell lineage was first obtained. (C) 2000 Academic Pr ess.