黄颡鱼PGRP-L基因克隆及其对爱德华氏菌的反应(英文)

MOLECULAR CHARACTERIZATION OF A LONG TYPE PEPTIDOGLYCAN RECOGNITION PROTEIN IN YELLOW CATFISH AND ITS RESPONSE TO EDWARDSIELLA ICTALURI

为了研究肽聚糖识别蛋白家族(Peptidoglycan recognition proteins,PGRPs)在黄颡鱼(Pelteobagrus fulvidraco)先天免疫应答中发挥的作用,根据NCBI中斑马鱼(Danio rerio)和虹鳟(Oncorhynchus mykiss)PGRP-L的基因信息,采用简并引物和RACE方法从黄颡鱼肝脏中克隆得到了一个长型PGRP(Pf PGRP-L)基因.Pf PGRP-L基因的全长c DNA序列大小为1617 bp,其中5′和3′非翻译区的长度分别为135和72 bp,开放阅读框为1410 bp,编码469个氨基酸.同源性和系统进化分析表明,黄颡鱼PGRP-L与虹鳟的同源性为60%,与脊椎动物的PGLYRP2或PGRP-L聚在一起.半定量RT-PCR分析发现Pf PGRP-L基因在黄颡鱼鳃、胸腺、肝脏、脾脏、肠道、肾脏、头肾、心脏、血液和肌肉组织中均有分布,但在肠道和脾脏中的表达量较为丰富,而在肌肉和血液中表达则很少.用爱德华氏菌刺激后,Pf PGRP-L在肝脏、脾脏、肠道及头肾中的表达明显上调.结果表明,Pf PGRP-L在黄颡鱼抵抗病原菌中具有重要作用.

Peptidoglycan recognition proteins （PGRPs） are a family of pattern recognition receptors （PRRs） of the immune system, exerting the direct antibacterial activity. A long-type PGRP （designated as PJPGRP-L） was identified from yellow catfish, Pelteobagrusfulvidraco. The entire PJPGRP-L cDNA is 1617 bp, including a 135 bp 5＇-UTR, a 72 bp 3＇-UTR and a 1401 bp open reading frame （ORF）. The deduced amino acid sequence of PJPGRP-L with 469 residues showed 60% identity with rainbow trout, Oncorhynchus mykiss PGRP-L. Conserved PGRP domain at the C-terminus was found in PJPGRP-L. Phylogenetic analysis demon- strated that PfPGRP-L was clustered in a same clade with Oncorhynchus mykiss, and formed a long-type PGRP subfamily together with vertebrate PGLYRP2 or PGRP-L members. RT-PCR analysis demonstrated that the mRNA of PJPGRP-L had similar expression patterns, being constitutively expressed in healthy yellow catfish, with the higher expression in intestine and spleen. By real-time PCR analysis, the transcription levels of PJPGRP-L in the liver, spleen, intestine and head kidney were significantly up-regulated after stimulated with Edwardsiella ictaluri. These results suggest that PJPGRP-L is involved in the defensive immune response against bacterial infection.