Sequence and expression of three members of the Sox gene in Amur sturgeon (Acipenser schrenckii)

Abstract

A cDNA encoding Sox4 was cloned from the ovary of the Amur sturgeon, Acipenser schrenckii. The cDNA encodes a protein of 372 amino acids (aa) with an HMG box and has a 69% amino acid sequence identity with the human Sox4. Moreover, two other Sox gene members (Sox2 and Sox9) were partially cloned. Among the various tissues tested, Sox4 mRNA was prominent in the heart, liver, kidney, eye and gonads (testis and ovary) at different development stages. The Sox2 expression pattern of gonads appears to be differently sex-specific sequenced, whereby the testis is highly expressed while the ovary is lowly expressed. Sox2 mRNA are also highly expressed in the eyes, kidney and liver tissue. Sox9 mRNA are ubiquitously expressed in the heart, kidney, liver, and eye, and Sox9 is also expressed during gonad development, but the level in the testis is slightly higher than in the ovary.

A review on sox genes in fish

“…The expression of sox9 is detected in gonads, muscles, brains, livers, fins, gills, kidneys, eyes and spleens of Siberian sturgeons ( A. baerii ), A. schrenckii and stellate sturgeons ( A. stellatus ) (Chen et al . 2010; Berbejillo et al . 2013; Burcea et al .…”

“…Sox24 is highly expressed in the ovary and detected in oocytes of Rainbow trout (Oncorhynchus mykiss), suggesting that sox24 plays a role as a transcriptional regulator during oogenesis (Kanda et al 1998). Sox4 was also expressed in the gonad of large yellow croaker (Larimichthys crocea), Amur sturgeon (Acipenser schrenckii), Chinese loach (Paramisgurnus dabryanus) and Mudloach (Misgurnus anguillicaudatus) (Chen et al 2010;Jiang et al 2016;Xia et al 2017b;Xia et al 2018b). Therefore, soxC (sox4, sox11 and sox24) is also thought to play an important role in sex differentiation of fish.…”

“…The signal of sox2 transcript in the retina and lens is detected in the embryos incubated with the antisense riboprobe in Crucian carp (Carassius auratus), suggesting that sox2 genes may have an important role in lens development (Marandel et al 2013). Sox2 is expressed in the different stages of eyes and gonads in A. schrenckii, while sox4 is expressed in multiple tissues, suggesting that sox2 plays an important role in the development of the sturgeon eyes and gonads at different stages, while sox4 plays an conserved role in the development of the heart, brain, spleen, kidney and reproductive systems (Chen et al 2010). Sox4 is highly expressed in heart and formation of eye lens of L. crocea, suggesting that sox4 plays an important role in the development of the visual system and heart (Jiang et al 2016).…”

“…Several studies have revealed that Sox9 is expressed in different tissues of both sexes of mammals, including outside of the gonads, suggesting that Sox9 is involved in defining progenitor cells in a variety of tissues in mammals (Stolt et al 2003;Zhou et al 2006). The expression of sox9 is detected in gonads, muscles, brains, livers, fins, gills, kidneys, eyes and spleens of Siberian sturgeons (A. baerii), A. schrenckii and stellate sturgeons (A. stellatus) (Chen et al 2010;Berbejillo et al 2013;Burcea et al 2018), similarly suggesting that sox9 is involved in defining progenitor cells in a variety of tissues in fish. These studies suggested that some sox genes play an important role in pigmentation, physiological and development processes in fish.…”

Multiple molecular approaches yield no evidence for sex-determining genes in lake sturgeon (Acipenser fulvescens)

“…For example, amur sturgeon ( Acipenser schrenckii ) express Sox genes differently in males and females. These genes code for transcription factors related to the mammalian Sry testis‐determining gene (Chen et al., 2006). While sexual differentiation may involve a suite of such genes, it may be difficult to determine a priori when and where these genes are expressed because the time of season, the age of the fish, the portion of gonadal tract sampled, and even nutritional considerations can all affect gene expression.…”