The Role of Maternal pou5f3.3/oct60 Gene in the Regulation of Initial Stages of Tissue Differentiation during Xenopus laevis Embryogenesis

The role of maternal Pou5f3.3/Oct60 factor of Xenopus laevis , a homolog of the pluripotency regulator of mammalian stem cells, the Oct4 protein, in early embryonic development was studied. It was shown that the maximum concentration of the Pou5f3.3/Oct60 protein is observed at the blastula stage, and then its degradation, stimulated by posttranslational modifications after the genome activation of the embryo, occurs. Using an approach based on Pou5f3.3/Oct60 overexpression in embryos, it was found that this protein activates expression of early pluripotency marker genes, pou5f3.2 , vent2.2 / 2.1 , klf 4 / 5 , but inhibits expression of cytoskeletal and cell adhesion genes: actin , claudin , zyxin , ldb3 . In addition, Pou5f3.3/Oct60 inhibits expression of ag1 / 2 and agr2 genes involved in the regulation of regenerative blastema differentiation in amputated limbs, as well as in the regulation of early brain development. Given the conservatism of early stages of development in vertebrates, the data obtained in the embryos of Xenopus laevis can be used to better understand the early development in mammals, including humans.