Identification of CPE and GAIT elements in 3’UTR of macrophage migration inhibitory factor (MIF) involved in inflammatory response induced by LPS in Ciona robusta

Abstract Innate immune responses face infectious microorganisms by inducing inflammatory responses. Multiple genes within distinct functional categories are coordinately and temporally regulated by transcriptional ‘on’ and ‘off’ switches that account for the specificity of gene expression in response to external stimuli. Mechanisms that control transcriptional and post-transcriptional regulation are important in coordinating the initiation and resolution of inflammation. Macrophage migration inhibitory factor (MIF) is an important cytokine that, in Ciona robusta , is related to inflammatory response. It is well known that in C. robusta, formerly known as Ciona intestinalis, the pharynx is involved in the inflammatory reaction induced by lipopolysaccharide (LPS) injection in the body wall. Using this biological system, we describe the identification of two C. robusta MIFs ( Cr MIF1 and Cr MIF2). The phylogenetic tree and modeling support a close relationship with vertebrate MIF family members. Cr MIF1 and Cr MIF2 possess two evolutionally conserved catalytic sites: a tautomerase and an oxidoreductase site with a conserved CXXC motif. Real-time PCR analysis shows a prompt expression induced by LPS inoculation in Cr MIF1 and a late upregulation of Cr MIF2 and in silico analyses of 3’UTR show a cis-acting GAIT element and a CPE element in 3’-UTR, which are not present in the 3’-UTR of Cr MIF1, suggesting that different transcriptional and post-transcriptional control mechanisms are involved in the regulation of gene expression of MIF during inflammatory response in C. robusta .