AUTHOR=Zhi Fei , Jiang Dong-Neng , Mustapha Umar Farouk , Li Shao-Xiang , Shi Hong-Juan , Li Guang-Li , Zhu Chun-Hua 

TITLE=Expression and regulation of 42Sp50 in spotted scat (Scatophagus argus)

JOURNAL=Frontiers in Genetics

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2022.964150

DOI=10.3389/fgene.2022.964150

ISSN=1664-8021

ABSTRACT=<p><italic>42Sp50</italic> is an isoform of the eukaryotic translation elongation factor 1 A (eEF1A) and is vital for fish ovarian development. Spotted scat (<italic>Scatophagus argus</italic>) is a popular marine cultured fish species in Southern Asia and China, and its artificial reproduction is complicated, with a relatively low success ratio in practice. In this study, the <italic>42Sp50</italic> gene was cloned from spotted scat. Tissue distribution analysis showed that <italic>42Sp50</italic> was mainly expressed in the ovary. qRT-PCR showed that <italic>42Sp50</italic> expression levels gradually decreased insignificantly in the ovaries from phase II to IV. Western blot analysis showed that <italic>42Sp50</italic> was highly expressed in the ovary, while it was almost undetectable in the testis. Immunohistochemistry analysis stained <italic>42Sp50</italic> mainly in the cytoplasm of the previtellogenic oocytes in ovaries of normal XX-female and sex-reversed XY-female. Aside from fish and amphibians, <italic>42Sp50</italic> was also identified in some reptile species using genomic database searching. Analyses of the transcriptome data from four different fish species (Hainan medaka (<italic>Oryzias curvinotus</italic>), silver sillago (<italic>Sillago sihama</italic>), Nile tilapia (<italic>Oreochromis niloticus</italic>), and Hong Kong catfish (<italic>Clarias fuscus</italic>)) revealed ovaries biased expression of <italic>42Sp50</italic> in all, similar to spotted scat. While the neighbor genes of <italic>42Sp50</italic> did not show ovary biased expression in the fish species analyzed. Bisulfite Sequencing PCR (BSP) results showed that the DNA methylation level of <italic>42Sp50</italic> promoter was low in ovaries, testes, and muscles. The luciferase reporter assay demonstrated that <italic>Dmrt4</italic> activated <italic>42Sp50</italic> expression in the presence of <italic>Sf1</italic> or <italic>Foxh1</italic>. These results suggest that <italic>42Sp50</italic> may be involved in regulating the early phase oocytes development of spotted scat.</p>