hsd17b1 is a key gene for ovarian differentiation of the Siberian sturgeon.

This is the first work using gonads from undifferentiated, genetically-sexed Siberian sturgeon describing expression changes in genes related to steroid synthesis and female and male sex differentiation. One factor identified as relevant for ovarian differentiation was the gene coding for the enzyme Hsd17b1, which converts estrone into estradiol-17β. hsd17b1 was highly activated in female gonads at 2.

Siberian sturgeon multi-tissue reference transcriptome database.

Motivation: Siberian sturgeon is a long lived and late maturing fish farmed for caviar production in 50 countries. Functional genomics enable to find genes of interest for fish farming. In the absence of a reference genome, a reference transcriptome is very useful for sequencing based functional studies.

Multi-tissue Siberian sturgeon RNA sequencing data.

Siberian sturgeon, Acipenser baerii, is a commercially valuable fish for flesh and caviar production and a threatened species. We produced transcriptomic data for ten tissues with relevance to puberty, reproduction, early development, growth and food intake. The data includes RNA-Seq read sets of brain, pituitary, anterior-kidney, kidney, stomach, liver, heart, embryonic, pre-larval, and immature gonad sequences.

RNA-Seq transcriptome data of undifferentiated and differentiated gonads of Siberian sturgeon.

RNA-Seq transcriptome data from twenty Siberian sturgeon gonads at different developmental stages is described: ten undifferentiated gonads, six gonads of immature males and four gonads from immature females. Siberian sturgeon, , is long-lived, late-maturing fish farmed in 50 countries but its production remains on a craftsman scale when compared to industrial species. Sturgeon genetic and physiological studies are less developed than for industrial fish.

De novo transcriptome analysis to search for sex-differentiation genes in the Siberian sturgeon.

The sturgeon family includes many species that are lucrative for commercial caviar production, some of which face critical conservation problems. The purpose of this study was to identify genes involved in gonadal sex differentiation in sturgeons, contributing to our understanding of the biological cycle of this valuable species. A high-quality de novo Siberian sturgeon gonadal transcriptome was built for this study using gonadal samples from undifferentiated fish at 3, 5, and 6 months of age; recently sex-differentiated fish at 9 months of age; and immature males and females at 14-17 months of age.

Sex hormone-binding globulin b expression in the rainbow trout ovary prior to sex differentiation.

Salmonids have two sex hormone-binding globulin (Shbg) paralogs. Shbga is mainly expressed in the liver, while Shbgb is secreted by the granulosa cells of the rainbow trout ovary. Coexpression of shbgb and the gonadal aromatase cyp19a1a mRNAs been observed in granulosa cells, suggesting a physiological coordination between Shbgb expression and estrogen synthesis.

Identification of the molecular sex-differentiation period in the Siberian sturgeon.

Sexual development prior to gonadal sex differentiation is regulated by various molecular mechanisms. In fish, a "molecular sex-differentiation period" has been identified in species for which sex can be ascertained prior to gonadal sex differentiation. The present study was designed to identify such a period in a species for which no genetic sex markers or monosex populations are available.

Expression of dmrt1 and sox9 during gonadal development in the Siberian sturgeon (Acipenser baerii).

The sex differentiation period of the Siberian sturgeon was investigated through expression profiling of two testicular markers (dmrt1 and sox9). At the molecular level, a clear sexual dimorphism of dmrt1 and sox9 was observed in 3-year-old fish with immature gonads, in which males showed higher expression of these genes. Among 16-month-old sturgeons cultured in Uruguay, gonad morphology analyses showed one group of fish with undifferentiated gonads and a second group which had started their histological differentiation into ovaries or testes.

Expression and phylogeny of candidate genes for sex differentiation in a primitive fish species, the Siberian sturgeon, Acipenser baerii.

The molecular mechanisms underlying testis differentiation in basal actinopterygian fish remains poorly understood. The sex differentiation period was investigated in the Siberian sturgeon, Acipenser baerii, by expression profiling of Sertoli cell transcription factors (dmrt1, sox9) that control testis differentiation in vertebrates; Leydig cell factors (cyp17a1, star) affecting androgen production; the androgen receptor (ar); a growth factor controlling testis development (igf1); and a gene coding for a gonadotropin hormone (lh). Two genes were characterised for the first time in the Siberian sturgeon (dmrt1, cyp17a1), while the others came from public databases.

Presence of 11-ketotestosterone in pre-differentiated male gonads of Odontesthes bonariensis.

The involvement of androgens during sex differentiation period was investigated in the pejerrey Odontesthes bonariensis, by classic biochemical studies and gonadal histology. We studied in particular whether the enzyme activities involved in 11-oxygenated androgen production were active in a gonadal/peritoneum complex (GPC) of very small larvae exposed to masculinizing temperatures previous to morphological sex differentiation (5 weeks post-hatching). The GPC was incubated with 17-hydroxyprogesterone ((3)H-17P), and the presence of 11-KT as major metabolite in early gonads undergoing masculine pathway after temperature treatment exposure is reported.

Sexual dimorphism in the brain aromatase expression and activity, and in the central expression of other steroidogenic enzymes during the period of sex differentiation in monosex rainbow trout populations.

Using genetic monosex male and female rainbow trout populations, the potential sex differences in the central expression of estrogen receptors (esr1, esr2a, esr2b), brain aromatase (cyp19a1b) and some other steroidogenic enzymes was studied over the period of sex differentiation (from 35 to 63 dpf: days post-fertilization) using quantitative polymerase chain reaction (q-PCR). In addition, aromatase activity was evaluated during this period. The results indicated that brain aromatase (cyp19a1b) expression and activity showed a clear and significant sexually dimorphic pattern with higher levels in male brain between 35 and 53 dpf before the time of gonad morphological differentiation.

Molecular characterization of cyp11a1 and cyp11b1 and their gene expression profile in pejerrey (Odontesthes bonariensis) during early gonadal development.

Sex steroids are known to be involved in gonadal differentiation in fish, but whether androgens are early mediators of testis differentiation remains unclear. We studied the sex-related developmental variations in the gene expression of two key enzymes involved in steroids and androgen synthesis (cyp11a1 and cyp11b1) in trunks and isolated gonads of pejerrey (Odontesthes bonariensis) larvae during and after the sex determination period. Also, and in order to have a better characterization of this process we studied the expression of Sertoli (dmrt1, amh, sox9) and Leydig (nr5a1 or sf-1) cell markers as well as a gene with higher expression in females (cyp19a1a).

Estrogen treatment up-regulates female genes but does not suppress all early testicular markers during rainbow trout male-to-female gonadal transdifferentiation.

In non-mammalian vertebrates, estrogens are key players in ovarian differentiation, but the mechanisms by which they act remain poorly understood. The present study on rainbow trout was designed to investigate whether estrogens trigger the female pathway by activating a group of early female genes (i.e.