title: Molecular cloning and mRNA expression of the peptidoglycan recognition protein gene HcPGRP1 and its isoform HcPGRP1a from the freshwater mussel Hyriopsis cumingi.
abstract: 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.
authors.affiliation: School of Environmental Science and Engineering , Huazhong University of Science and Technology , Wuhan , China . ; Department of Environmental Protection of Henan Province , Zhengzhou , China .
authors.forename: Ye
authors.initials: Y
authors.lastname: Tao
authors.affiliation: 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 .
authors.forename: Zi-Yan
authors.initials: ZY
authors.lastname: Yang
authors.affiliation: Henan Rural Energy & Environment Agency , Henan Provincial Department of Agriculture , Zhengzhou , China .
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Environmental Science and Engineering , Huazhong University of Science and Technology , Wuhan , China .
authors.forename: Hong-Juan
authors.initials: HJ
authors.lastname: Wu
keywords: Hyriopsis cumingi; expression pattern; gene cloning; innate immunity; peptidoglycan recognition protein