Transforming growth factor β (CiTGF-β) gene expression is induced in the inflammatory reaction of Ciona intestinalis

• A gene of the transforming grow factor are transcribed in Ciona intestinalis.
• The phylogenetic tree revealed that the CiTGF-β is related to mammalian TGF.
• Sequence analysis and structure showed that CiTGF-β share a common ancestor in the chordate lineages.
• The CiTGF-β mRNA were expressed in the vessels hemocytes of the pharynx.
• Real time -PCR analyses revealed that CiTGF-β mRNA expression was upregulated by LPS challenge.

Transforming growth factor (TGF-β) is a well-known component of a regulatory cytokines superfamily that has pleiotropic functions in a broad range of cell types and is involved, in vertebrates, in numerous physiological and pathological processes. In the current study, we report on Ciona intestinalis molecular characterisation and expression of a transforming growth factor β homologue (CiTGF-β). The gene organisation, phylogenetic tree and modelling supported the close relationship with the mammalian TGF suggesting that the C. intestinalis TGF-β gene shares a common ancestor in the chordate lineages. Functionally, real-time PCR analysis showed that CiTGF-β was transcriptionally upregulated in the inflammatory process induced by LPS inoculation, suggesting that is involved in the first phase and significant in the secondary phase of the inflammatory response in which cell differentiation occurs. In situ hybridisation assays revealed that the genes transcription was upregulated in the pharynx, the main organ of the ascidian immune system, and expressed by cluster of hemocytes inside the pharynx vessels. These data supported the view that CiTGF-β is a potential molecule in immune defence systems against bacterial infection.