Molecular evidence for the existence of two distinct IL-8 lineages of teleost CXC-chemokines

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• 作者：Nevien K. Abdelkhalek ; Asuka Komiya ; Yoko Kato-Unoki ; Tomonori Somamoto ; Miki Nakao
• 关键词：CXC-chemokine ; IL-8 ; C. carpio ; Teleost ; Evolution ; Phylogeny ; Cloning
• 刊名：Fish & Shellfish Immunology
• 出版年：2009
• 出版时间：December 2009
• 年：2009
• 卷：27
• 期：6
• 页码：763-767
• 全文大小：1268 K

文摘

Interleukin-8 (IL-8) is a CXC-type chemokine with a chemotactic activity mainly on neutrophils and plays a key role in promoting inflammation. In teleosts, several CXC-chemokines have been cloned and characterized as being IL-8-like. Phylogenetic data however indicate that the reported teleost IL-8-like chemokines are substantially remote from mammalian IL-8, forming a fish-specific clade of IL-8-like chemokines distinct from that of tetrapod IL-8. In the present study, a novel IL-8-like chemokine, designated CaIL-8, has been found in the expressed sequence tags of carp gills and identified as an orthologue of mammalian IL-8. The CaIL-8 transcript encodes 99 amino acids containing a typical CXC motif but lacks an ELR motif, as in most teleost IL-8-like chemokines. Phylogenetic tree constructed by the maximum likelihood method suggests a closer relationship of CaIL-8 with mammalian IL-8 than with other teleost CXC-chemokines reported to be IL-8-like. In a normal unstimulated carp, CaIL-8 mRNA was detected by RT-PCR only in gills, kidney, spleen, heart and peripheral blood leukocytes, in contrast to a previously reported carp IL-8-like chemokine CXCa, which shows ubiquitous basal expression. The results, taken together, are strongly indicative of the presence of two major IL-8-like lineages of CXC-chemokines in teleost.