Identification of embryonic stem cell activities in an embryonic cell line derived from marine medaka (Oryzias dancena).

This study was conducted to identify embryonic stem cell (ESC) activities of a long-term cultured embryonic cell line previously derived from blastula-stage Oryzias dancena embryos. Five sub-cell lines were established from the embryonic cell line via clonal expansion of single cells. ESC activities, including clonogenicity, alkaline phosphatase (AP) activity, and differentiation capacity, were examined in the five sub-cell lines. We observed both clonogenicity and AP activity in all five sub-cell lines, but the proportion of cells that exhibited both properties was significantly different among them. Even though we detected different formation rates and sizes of embryoid body (EB) among these cells, all lines were stably able to form EBs and further induction for differentiation showed their capability to differentiate into other cell types in a spontaneous manner. From this study, we determined that the embryonic cell lines examined possessed heterogeneous ESC activities and can be utilized as a marine model system for fish ESC-based research.