title: Hyriopsis cumingii Hic52-A novel nacreous layer matrix protein with a collagen-like structure.
abstract: Nacre is a product of a precisely regulated biomineralization process and a major contributor to the luster of pearls. Nacre is composed of calcium carbonate and an organic matrix of proteins that is secreted from mollusc mantle tissue and is exclusively associated with shell formation. In this study, hic52, a novel matrix protein gene from mantle of Hyriopsis cumingii, was cloned and functionally analyzed. The full-length cDNA of hic52 encoded 542 amino acids and contained a signal peptide of 18 amino acids. Excluding the signal peptide, the theoretical molecular mass of the polypeptide was 52.2kDa. The predicted isoelectric point was 10.37, indicating a basic shell protein. The amino acid sequence of hic52 featured high proportion of Gly (28.8%) and Gln (12.4%) residues. The predicted tertiary structure was characterized as having similarities to collagen I, alpha 1 and alpha 2 in the structure. The polypeptide sequence shared no homology with collagen. The hic52 expression pattern by quantitative real-time PCR and in situ hybridization exhibits at the dorsal epithelial cells of the mantle. Expression increased during the stages of pearl sac development. The data showed that hic52 is probably a framework shell protein that mediates and controls the nacreous biomineralization process.
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: Jingwen
authors.initials: J
authors.lastname: Pu
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai 201306, China.
authors.forename: Shimei
authors.initials: S
authors.lastname: Zeng
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: 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; E-Institute of Shanghai Universities, Shanghai Ocean University, Shanghai 201306, China. Electronic address: jlli2009@126.com.
authors.forename: Jiale
authors.initials: J
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D049872:Bivalvia / Q000737:chemistry* / Q000235:genetics; D003001:Cloning, Molecular; D003094:Collagen / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D008903:Minerals / Q000378:metabolism; D060734:Nacre / Q000737:chemistry*
chemical_list: D008903:Minerals; D060734:Nacre; D003094:Collagen
keywords: Biomineralization; Hyriopsis cumingii; Matrix protein; hic52