title: N-Terminal region is responsible for chemotaxis-inducing activity of flounder IL-8.
abstract: The objective of this study was to locate the functional region responsible for the chemotaxis-inducing activity of flounder interleukin 8 (IL-8), which lacks the glutamic acid-leucine-arginine (ELR) motif essential for the induction of neutrophil migration by mammalian IL-8. Using a human cell line, we produced a secretory recombinant protein of flounder IL-8, and analyzed its chemotaxis-inducing activity on leukocytes collected from the flounder kidney. The recombinant IL-8 induced significant migration in neutrophils, which were morphologically and functionally characterized. Using the Edman degradation method, the N-terminal amino acid sequence of rIL-8 was identified as VSLRSLGV. To examine the significance of the N-terminal region for the bioactivity of flounder IL-8, we prepared several recombinant proteins that containing mutations at the N-terminus. Modification of three residues (residues 9-11: serine-leucine-histidine) corresponding in position to the ELR motif in mammalian IL-8 did not reduce its chemotaxis-inducing activity. However, deletion of the first six or more residues significantly reduced its chemotaxis-inducing activity. We propose that residue 6 (leucine) at the N-terminus is important for the chemotaxis-inducing activity of flounder IL-8.
authors.affiliation: Laboratory of Aquatic Medicine, Department of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo 180-8602, Japan. Electronic address: kurata@nvlu.ac.jp.
authors.forename: Osamu
authors.initials: O
authors.lastname: Kurata
authors.affiliation: Laboratory of Aquatic Medicine, Department of Veterinary Science, Nippon Veterinary and Life Science University, 1-7-1 Kyonan-cho, Musashino, Tokyo 180-8602, Japan. Electronic address: swada@nvlu.ac.jp.
authors.forename: Shinpei
authors.initials: S
authors.lastname: Wada
authors.affiliation: National Research Institute of Aquaculture, Fisheries Research Agency, Minami-Ise, Mie 516-0193, Japan. Electronic address: matsuym@fra.affrc.go.jp.
authors.forename: Tomomasa
authors.initials: T
authors.lastname: Matsuyama
authors.affiliation: National Research Institute of Aquaculture, Fisheries Research Agency, Minami-Ise, Mie 516-0193, Japan. Electronic address: tasakai@affrc.go.jp.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Sakai
authors.affiliation: National Research Institute of Aquaculture, Fisheries Research Agency, Minami-Ise, Mie 516-0193, Japan. Electronic address: takanoto@affrc.go.jp.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Takano
mesh_terms: D000818:Animals; D002633:Chemotaxis; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D005412:Flatfishes / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D016209:Interleukin-8 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D029941:Fish Proteins; D016209:Interleukin-8; D011994:Recombinant Proteins
keywords: Chemokine; Neutrophil; Paralichthys olivaceus; Signaling domain; Teleost