School of Environmental Science and Engineering , Huazhong University of Science and Technology , Wuhan , China . ; Department of Environmental Protection of Henan Province , Zhengzhou , China .
School of Environmental Science and Engineering , Huazhong University of Science and Technology , Wuhan , China . ; School of Environment and Municipal Engineering , North China University of Water Resources and Electric Power , Zhengzhou , China .
Genet Mol Biol. 2014 Sep;37(3):508-17. doi: 10.1590/s1415-47572014000400006.
Peptidoglycan recognition proteins (PGRPs) are innate immune molecules that have been structurally conserved throughout evolution in invertebrates and vertebrates. In this study, peptidoglycan recognition protein HcPGRP1 and its isoform HcPGRP1a were identified in the freshwater mussel Hyriopsis cumingii. The full-length cDNAs of HcPGRP1 (973 bp) and HcPGRP1a (537 bp) encoded polypeptides with 218 and 151 amino acids, respectively. Sequence analysis showed that HcPGRP1 had one C-terminal PGRP domain that was conserved throughout evolution. Phylogenetic analysis showed that HcPGRP1 clustered closely with EsPGRP4 of Euprymna scolopes. Real-time PCR showed that the mRNA transcripts of HcPGRP1 and HcPGRP1a were constitutively expressed in various tissues, with the highest level in hepatopancreas. Stimulation with lipopolysaccharide (LPS) and peptidoglycan (PGN) significantly up-regulated HcPGRP1 mRNA expression in hepatopancreas and foot, but not in gill, whereas HcPGRP1a expression was significantly up-regulated in all three tissues. Our results indicate that HcPGRP1 is both a constitutive and inducible protein that may be involved in immune responses (recognition and defense) against invaders.
肽聚糖识别蛋白（PGRPs）是先天免疫分子，在无脊椎动物和脊椎动物中，其结构在进化过程中得到了保守。在本研究中，从淡水贻贝（Hyriopsis cumingii）中鉴定出了肽聚糖识别蛋白 HcPGRP1 及其同工型 HcPGRP1a。HcPGRP1（973 bp）和 HcPGRP1a（537 bp）的全长 cDNA 分别编码 218 个和 151 个氨基酸的多肽。序列分析表明，HcPGRP1 具有一个 C 端 PGRP 结构域，该结构域在进化过程中是保守的。系统进化分析表明，HcPGRP1 与 Euprymna scolopes 的 EsPGRP4 聚类密切。实时 PCR 显示，HcPGRP1 和 HcPGRP1a 的 mRNA 转录本在各种组织中均持续表达，在肝胰腺中表达水平最高。脂多糖（LPS）和肽聚糖（PGN）刺激显著上调了肝胰腺和足部的 HcPGRP1 mRNA 表达，但在鳃中没有上调，而 HcPGRP1a 在所有三个组织中的表达均显著上调。我们的结果表明，HcPGRP1 既是组成型蛋白又是诱导型蛋白，可能参与针对入侵物的免疫反应（识别和防御）。
