Characterisation of the finch embryo supports evolutionary conservation of the naïve stage of development in amniotes
Abstract
Innate pluripotency of mouse embryos transits from naïve to primed state as the inner cell mass (ICM) differentiates into epiblast. In vitro, their counterparts are embryonic (ESCs) and epiblast stem cells (EpiSCs) respectively. Activation of the FGF signalling cascade results in mouse ESCs differentiating into mEpiSCs, indicative of its requirement in the shift between these states. However, only mouse ESCs correspond to the naïve state; ESCs from other mammals and from chick show primed state characteristics. Thus, the significance of the naïve state is unclear. Here, we use zebra finch as a model for comparative ESC studies. The finch blastoderm has mESC-like properties, while chick blastoderm exhibits EpiSC features. In the absence of FGF signalling, finch cells retained expression of pluripotent markers, which were lost in cells from chick or aged finch epiblasts. Our data suggest that the naïve state of pluripotency is evolutionarily conserved among amniotes.
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© 2015, Mak et al.
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