Su Jianguo, Ni Duojiao, Song Linsheng, Zhao Jianmin, Qiu Limei
Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, PR China.
Fish Shellfish Immunol. 2007 Sep;23(3):646-56. doi: 10.1016/j.fsi.2007.01.023. Epub 2007 Feb 20.
Peptidoglycan recognition protein (PGRP) specifically binds to peptidoglycan and plays a crucial role in the innate immune responses as a pattern recognition receptor (PRR). The cDNA of a short type PGRP was cloned from scallop Chlamys farreri (named CfPGRP-S1) by homology cloning with degenerate primers, and confirmed by virtual Northern blots. The full length of CfPGRP-S1 cDNA was 1073 bp in length, including a 5' untranslated region (UTR) of 59 bp, a 3' UTR of 255 bp, and an open reading frame (ORF) of 759 bp encoding a polypeptide of 252 amino acids with an estimated molecular mass of 27.88 kDa and a predicted isoelectric point of 8.69. BLAST analysis revealed that CfPGRP-S1 shared high identities with other known PGRPs. A conserved PGRP domain and three zinc-binding sites were present at its C-terminus. The temporal expression of CfPGRP-S1 gene in healthy, Vibrio anguillarum-challenged and Micrococcus lysodeikticus-challenged scallops was measured by RT-PCR analysis. The expression of CfPGRP-S1 was upregulated initially in the first 12 h or 24 h either by M. lysodeikticus or V. anguillarum challenge and reached the maximum level at 24 h or 36 h, then dropped progressively, and recovered to the original level as the stimulation decreased at 72 h. There was no significant difference between V. anguillarum and M. lysodeikticus challenge. The results indicated that the CfPGRP-S1 was a constitutive and inducible acute-phase protein which was involved in the immune response against bacterial infection.
肽聚糖识别蛋白（PGRP）特异性结合肽聚糖，并作为模式识别受体（PRR）在先天免疫反应中发挥关键作用。通过简并引物同源克隆，从栉孔扇贝（Chlamys farreri）中克隆出一种短型PGRP的cDNA（命名为CfPGRP-S1），并通过虚拟Northern印迹法进行了确认。CfPGRP-S1 cDNA全长1073 bp，包括59 bp的5'非翻译区（UTR）、255 bp的3'UTR和759 bp的开放阅读框（ORF），编码一个由252个氨基酸组成的多肽，估计分子量为27.88 kDa，预测的等电点为8.69。BLAST分析表明，CfPGRP-S1与其他已知的PGRP具有高度同源性。其C末端存在一个保守的PGRP结构域和三个锌结合位点。通过RT-PCR分析测定了CfPGRP-S1基因在健康、鳗弧菌（Vibrio anguillarum）攻击和溶壁微球菌（Micrococcus lysodeikticus）攻击的扇贝中的时空表达。CfPGRP-S1的表达在溶壁微球菌或鳗弧菌攻击后的最初12小时或24小时内最初上调，并在24小时或36小时达到最高水平，然后逐渐下降，并随着刺激在72小时时减弱而恢复到原始水平。鳗弧菌和溶壁微球菌攻击之间没有显著差异。结果表明，CfPGRP-S1是一种组成型和诱导型急性期蛋白，参与了针对细菌感染的免疫反应。
