Establishment of a pluripotent cell line derived from a medaka (Oryzias latipes) blastula embryo.

A pluripotent cell line, OLES1, was established from a blastula embryo of a small freshwater fish, medaka (Oryzias latipes). Cells of this cell line were small and round, and they grew actively and stably in culture as dense clusters. They exhibited a positive alkaline phosphatase activity upon histochemical staining. When the cells were treated with retinoic acid, differentiation into various types of cells, including melanocytes, dopa-positive precursors of melanocytes, and cells with a molecular marker of skeletal muscles, troponin T, was induced in vitro. The present study opens a way to establishing embryonic stem cell lines in fish.