title: Identification of TGF-β, inhibin βA and follistatin paralogs in the rainbow trout genome.
abstract: Since their initial discovery, TGF-β superfamily members have been considered multifunctional growth and differentiation factors in many cell types. Various studies have clearly demonstrated the key roles of specific TGF-β members in muscle growth, including myostatin and inhibin as well as genes, such as follistatin. By binding to TGF-β members, follistatin prevents TGF-β from binding to its receptors and thus neutralizes its activity. Here, we report the identification of the gene sequences of four TGF-β isoforms and three paralogs of TGF-β1, which we called TGF-β1a, TGF-β1b and TGF-β1c, four sequences of inhibin βA paralogs; and two sequences of follistatin paralogs from rainbow trout. A phylogenetic analysis clearly indicated the existence of four monophyletic clades, corresponding to TGF-β1, -β2, -β3 and -β6. Based on their sequence identity TGF-β1a and -β1c are grouped together, whereas TGF-β1b appears more divergent even though it is grouped within the TGF-β1 clade. Alignments and phylogenetic analyses showed that the protein sequences of TGF-β, inhibin βA and follistatin are extremely well conserved (>90%) relative to each other; however, their regulation and expression patterns are different. TGF-β2 and -β3 showed the most abundant expression in muscle and were the main TGF-β members expressed in this tissue. Follistatin and inhibin βA paralogs were expressed in all tissues examined but with different patterns. Our identification of multiple copies of TGF-β, inhibin βA and follistatin with different expression patterns suggests non-redundant functions for these paralogs in rainbow trout.
authors.affiliation: Federal University of Rio Grande do Sul, Faculty of Agricultural Sciences, Research Group AQUAM, Aquaculture Sector, Department of Animal Science, Avenue Bento Gonçalves 7712, Agronomia, Porto Alegre 91540-000, RS, Brazil.
authors.forename: Fernanda
authors.initials: F
authors.lastname: de Mello
authors.affiliation: Federal University of Rio Grande do Sul, Faculty of Agricultural Sciences, Research Group AQUAM, Aquaculture Sector, Department of Animal Science, Avenue Bento Gonçalves 7712, Agronomia, Porto Alegre 91540-000, RS, Brazil.
authors.forename: Danilo Pedro
authors.initials: DP
authors.lastname: Streit
authors.affiliation: INRA, UR1037, Laboratory of Fish Physiology and Genomics, Growth and Flesh Quality Group, Campus de Beaulieu, 35000 Rennes, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Sabin
authors.affiliation: INRA, UR1037, Laboratory of Fish Physiology and Genomics, Growth and Flesh Quality Group, Campus de Beaulieu, 35000 Rennes, France. Electronic address: Jean-Charles.Gabillard@rennes.inra.fr.
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Gabillard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D038681:Follistatin / Q000235:genetics / Q000378:metabolism*; D016678:Genome; D028322:Inhibin-beta Subunits / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics* / Q000378:metabolism; D009928:Organ Specificity; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism; D059467:Transcriptome; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*
chemical_list: D038681:Follistatin; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; C103008:inhibin beta A subunit; D028322:Inhibin-beta Subunits
keywords: Fish; GDF11; Myostatin; Phylogenetic; Tissue expression