Expression of dmrt1 and vtg genes during gonad formation, differentiation and early maturation in cultured Russian sturgeon Acipenser gueldenstaedtii

Abstract

Expression of the dmrt1 and vtg genes was described using the real-time PCR (rt-PCR) method from 25 to 1600 days post-hatch (dph) in cultured Russian sturgeon Acipenser gueldenstaedtii. The level of dmrt1 transcription in gonads in subsequent studied periods increased exponentially while vtg expression increased in gonads and livers of A. gueldenstaedtii examined, but in later stages of development. Both dmrt1 and vtg genes showed elevated expression in intersex individuals probably caused by dietary exposure to phyto-oestrogens.

Expression Characterization of Six Genes Possibly Involved in Gonad Development for Stellate Sturgeon Individuals (Acipenser stellatus, Pallas 1771)

“…It could be feasible that the dmrt1 gene is expressed at higher levels in sturgeon males, independent of the number of copies that are present in the genome due to double dosage which appears for ZZ/ZW species. This has been observed in our study and in other research involving sturgeon species, such as A. fulvescens 13-14-year-old individuals (adolescent female and mature male) [ 31 ], A. baerii 3-year-old individuals with immature gonads [ 36 , 39 ], A. baerii 16–18-month-old juveniles [ 35 , 39 ], A. gueldenstaedtii 550-day-old and 1600-day-old individuals [ 40 ], and A. sinensis 3- and 4-year-old individuals. This could be due to specific targeting of dmrt1 gene by an unknown factor that determines a higher expression in males.…”

“…For the system of sex determination, the lack of dmrt1 expression in females is consistent with an XY system which appears not to be the case in sturgeons [ 40 ], where both females and males present the expression of this gene, which is in pattern with the ZW system of sex determination, where in birds, dmrt1 plays the role of master sex-determining gene [ 9 ]. It could be feasible that the dmrt1 gene is expressed at higher levels in sturgeon males, independent of the number of copies that are present in the genome due to double dosage which appears for ZZ/ZW species.…”

Early gonadal maturation and vitellogenin mRNA expression in Siberian sturgeon Acipenser baerii cultured in a semi-closed water recirculating system in Korea

“…From the vitellogenin gene expression assay, the expression was modulated toward upregulation during early gonadal maturity. It is similar with the elevated vitellogenin expression in accordance with either gonadal development or reproductive cycle, which has been observed not only in this chondrostean fish group but in other teleost species (Amberg et al, 2010;Zhang et al, 2011a;Hara et al, 2016;Fajkowska et al, 2016). In early works, vitellogenin has been originally thought as a mature female-specific protein since it is the main proteinogenic component of fish yolk, however, a number of subsequent studies have indicated that the transcription of vitellogenin gene is active also in both males and sexually immature fishes (Arukwe and Goksøyr, 2003;Zhang et al, 2005;Reading et al, 2018).…”

Dietary isoflavone intake and tissue concentration in cultured sturgeons

“…This bioaccumulation of phytoestrogens may therefore cause severe and chronic oestrogenic effect on hepatocytes by activating oestrogen receptor signalling pathways. The oestrogenic effect of commercial diets on sturgeons, measured by the induction of vitellogenin synthesis in the liver, or the increase of vitellogenin in blood plasma was previously reported by Pelissero, Le Menn, et al () and Fajkowska, Rzepkowska, Adamek, Ostaszewska, and Szczepkowski (). Also, in vitro analysis performed on sturgeon hepatocytes showed that all analysed isoflavones (genistein, daidzein, equol, biochanin A and formononetin) induced vitellogenin synthesis (Pelissero et al, ).…”