GATA4 Is a Transcriptional Regulator of SOX2 in Japanese Flounder (Paralichthys olivaceus)

GATA4, as a member of the GATA transcription factor family, plays a significant role in lineage specification and trans-differentiation of cells by regulating target gene expression. In this study, the potential transcription factor binding sites in the promoter of Paralichthys olivaceus sox2 gene were analyzed, and a GATA4-binding motif was identified. A cleaved amplified polymorphic sequence-based binding assay experiment was performed, and the results showed a significant binding process between the Homo sapiens GATA4 recombinant protein and the DNA fragment of P. olivaceus sox2 promoter. Luciferase reporter assay revealed that GATA4 could improve the activity of the P. olivaceus sox2 promoter. Overexpression of P. olivaceus GATA4 could also increase the sox2 mRNA expression level in flounder brain cells. Overall, our results indicate that sox2 is a target gene of GATA4 in P. olivaceus. Sox2 is implicated in the maintenance of stem cell pluripotency and can reprogram differentiated cells to iPS cells. In addition, sox2 is involved in the development of the central nervous system (CNS). Therefore, this study may provide a reference for exploring the function of P. olivaceus GATA4 in the regulation of pluripotent stem cells and the development of the CNS.