CAJ | 학술논문

　　鱼类多聚免疫球蛋白受体(polymeric immunoglobulin receptor, pIgR)是黏膜免疫系统的关键因子,能够介导多聚免疫球蛋白向黏液中的转运和分泌。本研究利用同源克隆和 cDNA 末端快速扩增技术(rapid amplification of cDNA ends, RACE),首次得到了大菱鲆(Scophthalmus maximus) pIgR完整的cDNA序列,全长1584 bp,该序列包含一个1005 bp的开放阅读框及5’和3’UTR,编码334个氨基酸。同源性比较发现,大菱鲆pIgR氨基酸序列与牙鲆(Paralichthys olivaceus)、斜带石斑鱼(Epinephelus coioides)、红鳍东方(Takifugu rubripes)的序列相似性分别是鲀74%、74%和59%,表现出较高的保守性。多序列比对显示,硬骨鱼pIgR包含两个ILD (Ig-like domain),分别对应哺乳类的ILD1和ILD5区域。系统进化树分析表明,大菱鲆pIgR和牙鲆的聚为一支。半定量RT-PCR显示, pIgR在健康大菱鲆各组织中均有表达,但表达水平不同,其中在黏膜相关淋巴组织中表达最强。经灭活的鳗弧菌菌液浸泡处理后,实时荧光定量PCR结果显示,大菱鲆各组织中pIgR的相对表达量在72 h内均呈现先增加后减少的趋势,在48 h内均有一个最高值出现,且黏膜相关淋巴组织中峰值出现较早,说明pIgR在硬骨鱼类黏膜免疫中发挥了重要作用。
　　어류다취면역구단백수체(polymeric immunoglobulin receptor, pIgR)시점막면역계통적관건인자,능구개도다취면역구단백향점액중적전운화분비。본연구이용동원극륭화 cDNA 말단쾌속확증기술(rapid amplification of cDNA ends, RACE),수차득도료대릉평(Scophthalmus maximus) pIgR완정적cDNA서렬,전장1584 bp,해서렬포함일개1005 bp적개방열독광급5’화3’UTR,편마334개안기산。동원성비교발현,대릉평pIgR안기산서렬여아평(Paralichthys olivaceus)、사대석반어(Epinephelus coioides)、홍기동방(Takifugu rubripes)적서렬상사성분별시돈74%、74%화59%,표현출교고적보수성。다서렬비대현시,경골어pIgR포함량개ILD (Ig-like domain),분별대응포유류적ILD1화ILD5구역。계통진화수분석표명,대릉평pIgR화아평적취위일지。반정량RT-PCR현시, pIgR재건강대릉평각조직중균유표체,단표체수평불동,기중재점막상관림파조직중표체최강。경멸활적만호균균액침포처리후,실시형광정량PCR결과현시,대릉평각조직중pIgR적상대표체량재72 h내균정현선증가후감소적추세,재48 h내균유일개최고치출현,차점막상관림파조직중봉치출현교조,설명pIgR재경골어류점막면역중발휘료중요작용。
Polymeric immunoglobulin receptor (pIgR) is a key immune factor, medicating the transport of poly-meric immunoglobulins (pIg) through the epithelial cells into the mucosal secretions to protect the organisms from pathogens. In this study, the pIgR of Scophthalmus maximus was first cloned and sequenced by rapid amplification of cDNA ends approaches (RACE). The pIgR contained 1 584 nucleotides, 3’UTR, 5’UTR, and an open reading frame (ORF) of 1 005 nucleotides that encoded for a polypeptide of 334 amino acid. Gene homology comparisons showed that S. maximus shared 74% amino acid identity with Paralichthys olivaceus and Epinephelus coioides, and 59%with Takifugu rubripes, indicating a high conservation of pIgR gene. Multiple sequence alignment dem-onstrated the pIgR of teleosts was composed of two Ig-like domains (ILDs), corresponding to the ILD1 and ILD5 of Mammal’s pIgR. The phylogenetic tree was constructed from the amino acid sequences of pIgR of 18 verte-brates and indicated that pIgR amino acids in S. maximus were clustered together with P. olivaceus. Expression analysis revealed that pIgR gene was expressed in almost all tissues of healthy S. maximuss, with higher levels in the mucosa-associated lymphoid tissues. The dynamics changes of pIgR expression in S. maximu were evaluated following bath immunization with inactivated Vibrio anguillarum by real-time PCR, and the results showed that the relative expression amount increased firstly and then decreased within 72 h in all the tested tissues, and reached its maximum expression within 48 h and the peak appeared earlier in mucosa-associated lymphoid tissues. These results suggested pIgR played a critical role in the mucosal immunity of teleost.