A novel immune-related gene, microtubule aggregate protein homologue, is up-regulated during IFN-γ-related immune responses in Japanese flounder, Paralichthys olivaceus.

Delayed-type hypersensitivity (DTH) response mediated by antigen-specific Th1 cells is used as a test to detect exposure to tuberculosis in humans. Japanese flounder (Paralichthys olivaceus) microtubule aggregate protein homologue (PoMTAP) was identified as a gene strongly induced during fish DTH response. In this study, PoMTAP gene was cloned and its expression profile was analyzed. The PoMTAP gene has a transcriptional regulatory region that includes two interferon-stimulated response elements and two IFN-γ activated sites. Expressions of PoMTAP and IFN-γ genes were up-regulated at the same time points during the DTH response, Edwardsiella tarda infection and VHSV infection. Furthermore, PoMTAP gene expressing cells also expressed CD3ε, confirming that PoMTAP is expressed by T lymphocytes. These results suggest that PoMTAP is a novel immune-related gene expressed by T lymphocytes that is preferentially induced by IFN-γ and has a role in Th1-mediated immune responses in Japanese flounder.