AUTHOR=Chi Heng , Meng Xianghu , Dalmo Roy Ambli 

TITLE=GATA-3 in Atlantic salmon (Salmo salar): Tissue distribution and its regulation of IL-4/13a promoter

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.1063600

DOI=10.3389/fcimb.2022.1063600

ISSN=2235-2988

ABSTRACT=<p>GATA3 is a transcription factor that plays an important role in T cell lineage differentiation and T-helper 2 (Th2) type immune responses. In this study, we developed two rat antibodies against Atlantic salmon GATA-3 (anti-r<italic>Ss</italic>GATA-3a and anti-r<italic>Ss</italic>GATA-3b, respectively). The western blotting and immunofluorescence results showed that anti-r<italic>Ss</italic>GATA-3b antibodies recognized endogenous <italic>Ss</italic>GATA-3 proteins, while the anti-r<italic>Ss</italic>GATA-3a antibodies did not bind <italic>Ss</italic>GATA-3. Immunohistochemical analysis revealed that <italic>Ss</italic>GATA-3 positive cells were detected in all tissues tested, with relatively high number of immune reactive cells in the gills and spleen. Furthermore, the immunohistochemical study revealed that <italic>Ss</italic>GATA-3 was expressed in pillar cells, epithelial cells, chondrocytes, perichondrium cells, and some undifferentiated basal cells. In addition, we determined 577 bp of the upstream promoter sequence of <italic>Ss</italic>IL-4/13a and found four motifs that matched <italic>Ss</italic>GATA-3 binding sites. The promoter regions of <italic>Ss</italic>IL-4/13a were assessed by transfecting four deletion reporter constructs and <italic>Ss</italic>GATA-3 overexpression plasmids. The result showed that <italic>Ss</italic>GATA-3 enhanced the activity of <italic>Ss</italic>IL-4/13a promoters within the region ranging from -317 to -302 bp upstream of the transcriptional start site. Antibodies against Th2 markers such as GATA-3 are valuable in addressing the diversity of T cell responses in fish.</p>