香鱼精氨酸酶Ⅱ基因的cDNA克隆及其表达与鳗弧菌感染的相关性

rginase II (Arg-II) is one kind of arginases. It can not only participate in the urea cycle, and but also have close relationship with pathological process. Here, we determined the ayu (Plecoglossus altivelis) Arg-II gene by de-novo transcriptome sequencing of ayu monocytes/macrophages. The cDNA sequence of ayu Arg-II is 4707 nucleotides, containing a large open reading frame that encodes a protein of 348 amino acids with a deduced molecular mass of 38.09 kD and a theoretical isoelectric point (pI) of 6.15. Multiple sequence alignment of complete amino acid sequences showed that ayu Arg-II had the typical characters of Arg-II in animals. Sequence comparsion showed that ayu Arg-II shared the highest amino acid sequence identity (85.3%) with that of rainbow trout (Oncorhynchus mykiss). Phylogenetic tree analysis also confirmed that ayu Arg-II falled into the fish Arg-II cluster and was most closely related to that of rainbow trout. Quantitative real-time PCR (qRT-PCR) analysis showed that ayu Arg-II mRNA had the highest expressional level in liver, brain and monocytes/macrophages derived from head kidney. Upon Vibrio anguillarum infection, ayu Arg-II transcripts significantly upregulated in the liver, brain, head kidney and monocytes/macrophages. In summary, our present study revealed a tight relationship between the ayu Arg-II expression and V. anguillarum infection, suggesting that ayu Arg-II plays an important role in fish immune response against bacteria infection. The present study provides a theoretical basis for studying the functions of fish Arg-II, and its molecular mechanism in regulating fish immune response to pathogens.