Characterization and gene expression of transcription factors, PU.1 and C/EBPα driving transcription from the tumor necrosis factor α promoter in Japanese flounder, <i>Paralichthys olivaceus</i>

Abstract

Both PU.1 and C/EBP alpha transcription factors play important roles in myeloid development and inflammatory response. These transcripts were cloned from the Japanese flounder (Paralichthys olivaceus) and were highly conserved with those of other vertebrates. PU.1 mRNA was mainly expressed in lymphoid tissues while C/EBP alpha mRNA was widely expressed in all tissues examined. Higher levels of PU.1 mRNA were expressed in the IgM(+) cells of both PBL and KL, while C/EBP alpha expression was higher only in the IgM(-) cells of KL The expression of C/EBP alpha mRNA was induced only in KL stimulated with LPS. Interestingly, PU.1 mRNA expression was induced by Edwardsiella tarda, whereas the expression of C/EBP alpha mRNA was induced by Streptococcus iniae infection. Both PU.1 and C/EBP alpha drove transcription from the LPS-responsive region of the Japanese flounder TNF alpha gene, suggesting that both PU.1 and C/EBP alpha induced by bacterial infection are involved in inflammation mediated through TNF alpha expression. (C) 2010 Elsevier Ltd. All rights reserved.