title: Expression and phylogeny of candidate genes for sex differentiation in a primitive fish species, the Siberian sturgeon, Acipenser baerii.
abstract: 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. Sturgeon gonad development is very slow, with a late sexual differentiation time during their juvenile stage, and are still immature at 3 years of age. Immature fish showed a sex-dimorphic pattern; all the genes studied displayed a higher expression level in male gonads. We took advantage of the presence of juvenile fish with pre- and post-differentiated gonads (16 and 18 months old) to characterise them at the molecular level. The post-differentiated fish displayed a sex dimorphism of gene expression in their gonads for all genes studied, with the exception of sox9. The trends in undifferentiated fish lead us to propose that sturgeons undergoing male differentiation express high levels of Sertoli cell factors (dmrt1, sox9) and of genes involved in the production and receptivity of androgens (cyp17a1, star and ar) together with lh. Expression profiles and phylogenetic studies suggest that these genes are potential regulators of testis development in the Siberian sturgeon.
authors.affiliation: Laboratorio de Fisiología de la Reproducción y Ecología de Peces, Instituto de Biología, Facultad de Ciencias, Universidad de la República Oriental del Uruguay, Montevideo, Uruguay.
authors.forename: Julio
authors.initials: J
authors.lastname: Berbejillo
authors.forename: Anabel
authors.initials: A
authors.lastname: Martinez-Bengochea
authors.forename: Gabriela
authors.initials: G
authors.lastname: Bedo
authors.forename: Frédéric
authors.initials: F
authors.lastname: Brunet
authors.forename: Jean-Nicolas
authors.initials: JN
authors.lastname: Volff
authors.forename: Denise
authors.initials: D
authors.lastname: Vizziano-Cantonnet
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D029941:Fish Proteins / Q000096:biosynthesis*; D005399:Fishes; D005786:Gene Expression Regulation / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis; D008297:Male; D010750:Phosphoproteins / Q000096:biosynthesis; D010802:Phylogeny; D012733:Sex Differentiation / Q000502:physiology*; D013254:Steroid 17-alpha-Hydroxylase / Q000096:biosynthesis; D013737:Testis / Q000166:cytology / Q000254:growth & development*; D014157:Transcription Factors / Q000096:biosynthesis; D059467:Transcriptome; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: C110547:DMRT1 protein; D029941:Fish Proteins; D010750:Phosphoproteins; D014157:Transcription Factors; D000098682:Steroidogenic Acute Regulatory Protein; D007334:Insulin-Like Growth Factor I; D013254:Steroid 17-alpha-Hydroxylase