Discordant proliferation and differentiation in pituitary tumor-transforming gene-null bone marrow stem cells

The mammalian securin, pituitary tumor-transforming gene (Pttg), regulates sister chromatid separation during mitosis. Mice deficient in Pttg expression exhibit organ-specific hypoplasia of the testis, spleen, pituitary, and postmaturity pancreatic β-cells, pointing to a possible adult stem cell defect. Bone marrow stem cells (BMSCs) contribute to bone, cartilage, and fat tissue repair and regeneration, and multipotent adult progenitor cells (MAPCs) have broader differentiation ability. Bone marrow cells derived under MAPC conditions are involved in a spectrum of tissue repair. We therefore tested whether Pttg deletion affects stem cell proliferation and differentiation. BMSCs were isolated under MAPC conditions, although unlike MAPCs, wild-type (WT) and Pttg−/− BMSCs do not express octamer-binding transcription factor 4 and are stem cell antigen-I positive. WT and Pttg−/− cells did not differ in their ability to differentiate into adipogenic, osteogenic, or hepatocyte-like cells or in phenotypic markers....