Molecular characterisation of sea bream (Sparus aurata) transforming growth factor β1

A transforming growth factor β1 (TGF β1) full length cDNA was characterised and sequenced from the head kidney of sea bream (Sparus aurata) previously challenged with a nodavirus. The cloned cDNA of 1778 bp contains a predicted open reading frame of 379 amino acids, which includes the mature peptide region of 112 amino acids. The regulating region of the peptide possesses four potential N-linked glycosylation sites (N-X-T/S), as well as an RGD integrin binding site, an RKKR tetrabasic cut site and nine conserved cysteines all characteristic of the TGF β superfamily. Compared to other teleost TGF β1 genes, the sea bream TGF β1 is most closely related to hybrid striped bass (Moronesaxatilis ×M. chrysops) TGF β1 (80% amino acid identity). nomic organisation of TGF β1 was determined through the generation of contiguous PCR clones. The sea bream TGF β1 gene is approximately 3·6 kb in length and consists of five coding regions. Two introns are absent in comparison to the genomic organisation of rainbow trout Oncorhynchus mykiss TGF β1, whilst an additional intron not present in other sequenced TGF β genes, but present in the trout TGF β1 gene, is conserved in sea bream. rse transcription polymerase chain reaction (RT-PCR) assay was developed to study TGF β expression in different sea bream tissues. Constitutive TGF β1 expression was detected in the liver, brain, muscle, kidney, heart, gills and spleen of sea bream, as well as in head kidney macrophages and blood leucocytes.