Survey on the role of maternal Activin-like factors in expression pattern of the pluripotency factors during early zebrafish development

The role of Activin-like factors in pluripotency maintenance is unknown during the zebrafish development. In this study, the embryos were treated with Activin A after dechorionation. Nanog and Oct4 expression patterns were evaluated during 256-cell, 1K, oblong, dome and shield stages (three replicates per stage). Due to the activation of cell signaling pathways before ZGA (zygotic genome activation), Activin treatment led to higher phosphorylation of Smad2/3 and progressively higher rate of Nanog expression in comparison to the control group at 1K-cell stage. At the oblong stage Nanog mRNA levels significantly decreased, therefore, Nanog mRNA levels should be reached to its peak in earlier time. Activin-like factors enhancement decreased Oct4 mRNA levels in contrast with Nanog. Due to the conservation of Activin-like factors pathway, the results can be generalized to other vertebrates and also provide a background for further studies, because of the stem cell importance.