Pooh cells

POU5F1 (more commonly known as Oct-4/3) is one of the stem cell markers and affects direction of differentiation in embryonic stem cells. To investigate whether cells of mesenchymal origin acquire embryonic phenotype, we generated a human cell line of mesodermal origin with overexpression of the chimeric POU5F1 gene with physiological co-activator EWS, which is driven by the potent EWS promoter by translocation. The cell line termed Pooh (POU5F1/Oct-4/3 overexpressing human) cells expressed embryonic stem cell genes such as Nanog and also non-translocated POU5F1, lost mesenchymal phenotypes, and exhibited embryonal stem cell-like alveolar structure when implanted into the subcutaneous tissue of immunodeficient mice. Hierarchical analysis by microchip analysis and cell surface analysis revealed that Pooh cells are subcategorized into the group of human embryonic stem cells and embryonal carcinoma cells. These results imply that cells of mesenchymal origin can partially be traced back to cells to embryonic phenotype by the POU5F1 gene in collaboration with the potent cis-regulatory element and the fused co-activator.

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Makino H, Toyoda M, Matsumoto K, Saito H, Nishino K, Fukawatase Y, Machida M, Akutsu H, Uyama T, Miyagawa Y, Okita H, Kiyokawa N, Fujino T, Ishikawa Y, Nakamura T, Umezawa A