title: Four invertebrate-type lysozyme genes from triangle-shell pearl mussel (Hyriopsis cumingii).
abstract: Lysozymes in animals have three types, namely chicken-type, goose-type, and invertebrate-type (i-type) lysozymes and all these 3 types have been found in bivalve mollusks. The i-type lysozymes in mollusks are involved in digestion and innate immunity. In this study, four different lysozyme genes that belong to i-type were identified from Hyriopsis cumingii. The HcLyso1 to HcLyso4 genes encode proteins with 144, 144, 161, and 228 amino acids, respectively, and contain a destabilase domain. HcLyso4 also contains SH3b domain in addition to its destabilase domain. Multiple alignments showed that two catalytic residues of Glu and Asp which were necessary for enzyme activity were present in i-type lysozymes. Phylogenetic analysis using CDS sequences of i-type lysozymes showed that these lysozymes can be divided into mollusk and crustacean clades, and that HcLyso1 to HcLyso4 all belong to the mollusk clades. Although there was no positive selection predicted in i-type lysozymes, some branches suffered rapid evolution. HcLyso1 is mainly expressed in hepatopancreas and can be detected in hemocytes. HcLyso2 is primarily expressed in hepatopancreas and can be detected in hemocytes Whereas, HcLyso3 can be detected mainly in hemocytes, hepatopancreas, gills, and mantle. HcLyso4 is expressed in hemocytes and hepatopancreas. qRT-PCR analysis showed that HcLyso1 to HcLyso4 were all nearly down-regulated by Vibrio or Staphylococcus aureus challenge. Moreover, our research indicated that HcLyso1 to HcLyso4 might play a key role in the innate immunity of mussel.
authors.affiliation: Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, China. renqian0402@126.com
authors.forename: Qian
authors.initials: Q
authors.lastname: Ren
authors.forename: Yin-Le
authors.initials: YL
authors.lastname: Qi
authors.forename: Kai-Min
authors.initials: KM
authors.lastname: Hui
authors.forename: Zhao
authors.initials: Z
authors.lastname: Zhang
authors.forename: Chi-Yu
authors.initials: CY
authors.lastname: Zhang
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D009113:Muramidase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D009928:Organ Specificity; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment; D013211:Staphylococcus aureus / Q000276:immunology; D049876:Unionidae / Q000737:chemistry / Q000235:genetics* / Q000276:immunology*; D014733:Vibrio / Q000276:immunology
chemical_list: D018076:DNA, Complementary; D009113:Muramidase