Acquisition of pluripotency in the chick embryo occurs during intrauterine embryonic development via a unique transcriptional network.

BACKGROUND

Acquisition of pluripotency by transcriptional regulatory factors is an initial developmental event that is required for regulation of cell fate and lineage specification during early embryonic development. The evolutionarily conserved core transcriptional factors regulating the pluripotency network in fishes, amphibians, and mammals have been elucidated. There are also species-specific maternally inherited transcriptional factors and their intricate transcriptional networks important in the acquisition of pluripotency. In avian species, however, the core transcriptional network that governs the acquisition of pluripotency during early embryonic development is not well understood.

RESULTS

We found that chicken () was expressed in the stages between the pre-ovulatory follicle and oocyte and was continuously detected in Eyal-Giladi and Kochav stage I (EGK.I) to X. However, was not expressed during folliculogenesis, but began to be detectable between EGK.V and VI. Unexpectedly, could not be detected during folliculogenesis and intrauterine embryonic development. Instead of , was maternally inherited and continuously expressed during chicken intrauterine development. In addition, we found that the pluripotency-related genes such as , , , , , and began to be dramatically upregulated between EGK.VI and VIII.

CONCLUSION

These results suggest that chickens have a unique pluripotent circuitry since maternally inherited c and may play an important role in the initial acquisition of pluripotency. Moreover, the acquisition of pluripotency in chicken embryos occurs at around EGK.VI to VIII.