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

Innate immune responses face infectious microorganisms by inducing inflammatory responses. Multiple geneswithin 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 thatcontrol transcriptional and post-transcriptional regulation are important in coordinating the initiation and resolutionof inflammation. Macrophage migration inhibitory factor (MIF) is an important cytokine that, in Cionarobusta, 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 inthe body wall. Using this biological system, we describe the identification of two C. robusta MIFs (CrMIF1 andCrMIF2). The phylogenetic tree and modeling support a close relationship with vertebrate MIF family members.CrMIF1 and CrMIF2 possess two evolutionally conserved catalytic sites: a tautomerase and an oxidoreductasesite with a conserved CXXC motif. Real-time PCR analysis shows a prompt expression induced by LPS inoculationin CrMIF1 and a late upregulation of CrMIF2 and in silico analyses of 3’UTR show a cis-acting GAIT element and aCPE element in 3’-UTR, which are not present in the 3’-UTR of CrMIF1, suggesting that different transcriptionaland post-transcriptional control mechanisms are involved in the regulation of gene expression of MIF duringinflammatory response in C. robusta.