title: Silkmapin of Hyriopsis cumingii, a novel silk-like shell matrix protein involved in nacre formation.
abstract: Understanding the role of matrix proteins in nacre formation and biomineralization in mollusks is important for the pearl industry. In this study, the gene encoding the novel Hyriopsis cumingii shell matrix protein silkmapin was characterized. The gene encodes a protein of 30.89kDa in which Gly accounts for 34.41% of the amino acid content, and the C-terminal region binds Ca(2+). Secondary structure prediction indicated a predominantly β-fold and a structure typical of filamentous proteins. Real-time quantitative PCR and in situ hybridization showed that silkmapin was expressed in epithelial cells at the edge and pallial of mantle tissue, indicated that silkmapin play roles in the shell nacreous and prismatic layer formation. Further real-time PCR results indicated an involvement in pearl formation via nucleation of calcium carbonate prior to formation of the nacre.
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China.
authors.forename: Shaojian
authors.initials: S
authors.lastname: Dong
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China.
authors.forename: Can
authors.initials: C
authors.lastname: Jin
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China.
authors.forename: Zhiyi
authors.initials: Z
authors.lastname: Bai
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China.
authors.forename: Guiling
authors.initials: G
authors.lastname: Wang
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China; E-Institute of Shanghai Universities, Shanghai Ocean University, Shanghai 201306, China; Mobile postdoctoral center of Agriculture, Shanghai Ocean University, Shanghai 201306, China. Electronic address: jlli@shou.edu.cn.
authors.forename: Jiale
authors.initials: J
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D060105:Animal Shells / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D002119:Calcium Carbonate / Q000378:metabolism*; D003001:Cloning, Molecular; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D060734:Nacre / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D047011:Silk / Q000378:metabolism*; D049876:Unionidae / Q000378:metabolism*
chemical_list: D060734:Nacre; D011506:Proteins; D047011:Silk; D002119:Calcium Carbonate; D002118:Calcium
keywords: Biomineralization; Freshwater mussel; Hyriopsis cumingii; Matrix protein; Nacre