title: In-depth proteomic analysis of nacre, prism, and myostracum of Mytilus shell.
abstract: Mytilus is an economically important bivalve and its shell is a biomineralized tissue with various microstructures/layers. In the present study, the shell of marine mussel, Mytilus coruscus, was analyzed and three shell layers with different morphologies and polymorphs were observed, which includes nacre, fibrous prism, and myostracum strongly attached by adductor muscles to the interior of the shell surface. In order to understand whether these different shell layers contain different shell matrix proteins (SMPs), the transcriptome sequencing of M. coruscus mantle and a parallel proteomic analysis of SMPs in the three shell layers were performed. A combination of LC-MS/MS analysis with the mantle transcriptome dataset search resulted in the identification of a total of 63 proteins from M. coruscus shell. From this protein set, fifteen, fourteen, and eight proteins were found to be unique to nacre, fibrous prism, and myostracum layers, respectively. In addition, many novel shell proteins were also identified. The data in this study could be used as a background to explore the roles of SMPs in the deposition of different shell layers (nacre vs. fibrous prism vs. myostracum), the different polymorphisms of calcium carbonate (aragonite vs. calcite); and further, the identified proteins from the myostracum could provide candidates for studying the mechanism of adductor muscle-shell attachment.
  
  
  CONCLUSIONS
  In this paper, we characterized for the first time the protein set from different shell layers in Mytilus. Shell matrix proteins are the major component that controls different aspects of the shell formation process and thus a source of bioactive molecules that would offer interesting perspectives in biomaterials and biomedical fields. Our data can be used as a resource for further exploring the roles of shell matrix proteins in the deposition of different shell layers (nacre vs. fibrous prism vs. myostracum) or different polymorphisms of calcium carbonate (aragonite vs. calcite), and the identified protein set of myostracum provided candidates for studying the mechanism of adductor muscle-shell attachment.
authors: Laboratory of Marine Biological Protein Engineering, Zhejiang Ocean University, Zhoushan, Zhejiang, China. Electronic address: liaozhi@zjou.edu.cn.
authors: Zhi
authors: Z
authors: Liao
authors: Laboratory of Marine Biological Protein Engineering, Zhejiang Ocean University, Zhoushan, Zhejiang, China.
authors: Lin-fei
authors: LF
authors: Bao
authors: Laboratory of Marine Biological Protein Engineering, Zhejiang Ocean University, Zhoushan, Zhejiang, China.
authors: Mei-hua
authors: MH
authors: Fan
authors: Laboratory of Marine Biological Protein Engineering, Zhejiang Ocean University, Zhoushan, Zhejiang, China.
authors: Peng
authors: P
authors: Gao
authors: Laboratory of Marine Biological Protein Engineering, Zhejiang Ocean University, Zhoushan, Zhejiang, China.
authors: Xin-xing
authors: XX
authors: Wang
authors: Laboratory of Marine Biological Protein Engineering, Zhejiang Ocean University, Zhoushan, Zhejiang, China.
authors: Chuan-Li
authors: CL
authors: Qin
authors: Biotechnology Center, Chinese Academy of Fishery Science, Beijing, China.
authors: Xiao-Min
authors: XM
authors: Li
mesh_terms: D000595:Amino Acid Sequence; D060105:Animal Shells / Q000378:metabolism*; D000818:Animals; D030562:Databases, Protein; D008969:Molecular Sequence Data; D049878:Mytilus / Q000235:genetics / Q000378:metabolism*; D020543:Proteome / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics
chemical_list: D020543:Proteome
keywords: Mantle; Myostracum; Mytilus coruscus; Proteome; Shell; Transcriptome