title: The duplicated rainbow trout (Oncorhynchus mykiss) T-box transcription factors 1, tbx1a and tbx1b, are up-regulated during testicular development.
abstract: Tbx1 is a member of the T-box transcription factor gene family involved in embryogenesis and organogenesis. Recently, within a pan-genomic screen using rainbow trout (Oncorhynchus mykiss) cDNA microarrays, we identified a tbx1 homolog with testicular over-expression during sex differentiation. Here, we characterized two very similar rainbow trout tbx1 paralogs, tbx1a and tbx1b. In adult tissues, tbx1a expression is restricted to the gonads, with high expression in the testis, while tbx1b is more widely expressed in gonads, gills, brains, muscle, and skin. During gonadal differentiation, both genes are differentially expressed in favor of testis formation shortly after hatching. These genes are expressed in somatic cells surrounding germ cells of the differentiating testis, while no or only weak expression was observed in the differentiating ovary. tbx1a and tbx1b were also both down-regulated in the differentiating testis during feminization with estrogens and up-regulated in the differentiating ovary during masculinization with an aromatase inhibitor. These results suggest that tbx1a and tbx1b are probably involved in the regulation of testicular differentiation in rainbow trout. Since Tbx1 is known to interact with the retinoic acid (RA) signaling pathway, we also examined the effect of RA on the rainbow trout tbx1 expression pattern. Expression of tbx1a and tbx1b was down-regulated in RA-treated male gonads, suggesting that tbx1 interacts with the RA signaling pathway and thus could be involved in the control of rainbow trout gonadal differentiation.
authors.affiliation: INRA, UR1037 SCRIBE, IFR140, Ouest-Genopole, Rennes, France.
authors.forename: Ayaka
authors.initials: A
authors.lastname: Yano
authors.forename: Barbara
authors.initials: B
authors.lastname: Nicol
authors.forename: Adele
authors.initials: A
authors.lastname: Guerin
authors.forename: Yann
authors.initials: Y
authors.lastname: Guiguen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D047072:Aromatase Inhibitors / Q000494:pharmacology; D019295:Computational Biology; D017931:DNA Primers / Q000235:genetics; D004967:Estrogens / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D020131:Genes, Duplicate / Q000235:genetics; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000254:growth & development*; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D016415:Sequence Alignment; D020825:T-Box Domain Proteins / Q000235:genetics / Q000378:metabolism*; D013737:Testis / Q000254:growth & development* / Q000378:metabolism; D014212:Tretinoin / Q000494:pharmacology
chemical_list: D047072:Aromatase Inhibitors; D017931:DNA Primers; D004967:Estrogens; D020825:T-Box Domain Proteins; D014212:Tretinoin