Cloning and sequence analysis of the interleukin-8 gene from flounder (Paralichthys olivaceous)

A cDNA library of mRNA from flounder leukocytes stimulated with bacterial l ipopolysaccharide (LPS) and hemagglutinin was constructed to clone cytokine genes of this fish. Initial screening of this library with human cytokine gene probes was not productive and clones with inserts of over 400 nucleoti des (nt) were randomly sequenced, and a homologue of the vertebrate interle ukin-8 (IL-8) gene was isolated. The flounder IL-8 cDNA encompassed 884 nt, including a coding region of 330 nt. Four cysteines characteristic of CXC chemokines were identified at conserved locations in the putative protein. The deduced amino acid sequence showed 36 and 35% sequence identity with co unterpart genes in monkey and human, respectively, and 52% sequence similar ity with these genes. However, the putative flounder IL-8 amino acid sequen ce showed 25% identity and 52% similarity to that of lamprey, the only othe r piscine IL-8 gene that has been cloned. Flounder IL-8 transcripts were de tected in the head-kidney and spleen of LPS-injected flounder and leukocyte s stimulated with LPS. It was not detected in the muscle or Ever of LPS-inj ected flounder, tissues taken from non-stimulated flounder and non-stimulat ed leukocytes. (C) 2001 Elsevier Science B.V. All rights reserved.