Molecular Evolution and Functional Characterization of Lethenteron reissneri STAT3

Abstract

STAT3, as a member of the STAT family, is involved in biological processes such as cell proliferation, apoptosis, differentiation, and immune regulation. In this study, a homologue of STAT3 was cloned from Lethenteron reissneri, that is, L. reissneri STAT3. The molecular evolution of L. reissneri STAT3 gene was systematically analyzed, including motif, exon, and collinear analyses. The motif analysis revealed that L. reissneri STAT3 gene was conserved with respect to some motif compositions, except motifs 14–18. A slight difference was observed in the STAT3 exon numbers among different species, which indicates that L. reissneri STAT3 gene was relatively conserved during the evolutionary process. However, the collinear analysis showed that the adjacent genes of STAT3 in different species varied, implying that the chromosome where the L. reissneri STAT3 gene is located might have undergone chromosomal rearrangement. L. reissneri STAT3 gene was expressed in various tissues, and it was highly expressed in kidney and gills. L. reissneri STAT3was expressed differentially after lamprey was stimulated with lipopolysaccharide, which suggests that L. reissneri STAT3 was involved in lamprey immune regulation. The cell activity of STAT3 transient expression group in MCF-7 cells was higher than that in the control group. Flow cytometry analysis showed that overexpression of L. reissneri STAT3 in MCF-7 cells inhibited the apoptosis of MCF-7 cells. However, the function of STAT3 in lamprey remains to be explored. The molecular evolution, expression, and function analysis of L. reissneri STAT3 could provide a theoretical basis for further exploration of STAT3-mediated adaptive immune regulation in lamprey.