title: Macrophage migration inhibitory factor (MIF) family in arthropods: Cloning and expression analysis of two MIF and one D-dopachrome tautomerase (DDT) homologues in mud crabs, Scylla paramamosain.
abstract: The macrophage migration inhibitory factor (MIF) family, consisting of MIF and D-dopachrome tautomerase (DDT) in vertebrates, is evolutionarily ancient and has been found across Kingdoms including vertebrates, invertebrates, plants and bacteria. The mammalian MIF family are chemokines at the top of the inflammatory cascade in combating infections. They also possess enzymatic activities, e.g. DDT catalysis results in the production of 5,6-dihydroxyindole (DHI), a precursor of eumelanin. MIF-like genes are widely distributed, but DDT-like genes have only been described in vertebrates and a nematode. In this report, we cloned a DDT-like gene, for the first time in arthropods, and a second MIF in mud crab. The mud crab MIF family have a three exon/two intron structure as seen in vertebrates. The identification of a DDT-like gene in mud crab and other arthropods suggests that the separation of MIF and DDT preceded the divergence of protostomes and deuterostomes. The MIF family is differentially expressed in tissues of adults and during embryonic development and early life. The high level expression of the MIF family in immune tissues, such as intestine and hepatopancreas, suggests an important role in mud crab innate immunity. Mud crab DDT is highly expressed in early embryos, in megalops and crablets and this coincides with the requirement for melanisation in egg chorion tanning and cuticular hardening in arthropods, suggesting a potential novel role of DDT in melanogenesis via its tautomerase activity to produce DHI in mud crab. The clarification of the presence of both MIF and DDT in this report paves the way for further investigation of their functional roles in immunity and in melanogenesis in mud crab and other arthropods.
authors.affiliation: Fishery College, Jimei University, Xiamen 361021, China; Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education PRC, Xiamen 361021, China. Electronic address: wshuang@jmu.edu.cn.
authors.forename: Wen-Shu
authors.initials: WS
authors.lastname: Huang
authors.affiliation: Fishery College, Jimei University, Xiamen 361021, China; Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education PRC, Xiamen 361021, China.
authors.forename: Li-Peng
authors.initials: LP
authors.lastname: Duan
authors.affiliation: Fishery College, Jimei University, Xiamen 361021, China; Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education PRC, Xiamen 361021, China.
authors.forename: Bei
authors.initials: B
authors.lastname: Huang
authors.affiliation: Fujian Collaborative Innovation Center for Development and Utilization of Marine Biological Resources, Xiamen 361005, China.
authors.forename: Ke-Jian
authors.initials: KJ
authors.lastname: Wang
authors.affiliation: Fishery College, Jimei University, Xiamen 361021, China; Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education PRC, Xiamen 361021, China.
authors.forename: Cai-Liang
authors.initials: CL
authors.lastname: Zhang
authors.affiliation: Fishery College, Jimei University, Xiamen 361021, China; Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education PRC, Xiamen 361021, China.
authors.forename: Qin-Qin
authors.initials: QQ
authors.lastname: Jia
authors.affiliation: Fishery College, Jimei University, Xiamen 361021, China.
authors.forename: Pin
authors.initials: P
authors.lastname: Nie
authors.affiliation: Scottish Fish Immunology Research Centre, Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen AB24 2TZ, UK. Electronic address: t.h.wang@abdn.ac.uk.
authors.forename: Tiehui
authors.initials: T
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D060829:Arthropod Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D003386:Brachyura / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D019746:Intramolecular Oxidoreductases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008263:Macrophage Migration-Inhibitory Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D009928:Organ Specificity; D010802:Phylogeny; D012313:RNA / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D060829:Arthropod Proteins; D018076:DNA, Complementary; D008263:Macrophage Migration-Inhibitory Factors; D012313:RNA; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase
keywords: Cloning; D-dopachrome tautomerase (DDT); Expression analysis; Gene organisation; Macrophage migration inhibitory factor (MIF); Mud crab Scylla paramamosain