title: Isolation and characterization of a novel acidic matrix protein hic22 from the nacreous layer of the freshwater mussel, Hyriopsis cumingii.
abstract: Matrix proteins that either weakly acidic or unusually highly acidic have important roles in shell biomineralization. In this study, we have identified and characterized hic22, a weakly acidic matrix protein, from the nacreous layer of Hyriopsis cumingii. Total protein was extracted from the nacre using 5 M EDTA and hic22 was purified using a DEAE-sepharose column. The N-terminal amino acid sequence of hic22 was determined and the complete cDNA encoding hic22 was cloned and sequenced by rapid amplification of cDNA ends-polymerase chain reaction. Finally, the localization and distribution of hic22 was determined by in situ hybridization. Our results revealed that hic22 encodes a 22-kDa protein composed of 185 amino acids. Tissue expression analysis and in situ hybridization indicated that hic22 is expressed in the dorsal epithelial cells of the mantle pallial; moreover, significant expression levels of hic22 were observed after the early formation of the pearl sac (days 19-77), implying that hic22 may play an important role in biomineralization of the nacreous layer.
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai, China.
authors.forename: X J
authors.initials: XJ
authors.lastname: Liu
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai, China.
authors.forename: C
authors.initials: C
authors.lastname: Jin
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai, China.
authors.forename: L M
authors.initials: LM
authors.lastname: Wu
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai, China.
authors.forename: S J
authors.initials: SJ
authors.lastname: Dong
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai, China.
authors.forename: S M
authors.initials: SM
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Freshwater Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Agriculture, Shanghai, China jlli2009@126.com.|E-Institute of Shanghai Universities, Shanghai Ocean University, Shanghai, China jlli2009@126.com.
authors.forename: J L
authors.initials: JL
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004847:Epithelial Cells; D016326:Extracellular Matrix Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D009928:Organ Specificity; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D049876:Unionidae / Q000166:cytology / Q000378:metabolism*
chemical_list: D016326:Extracellular Matrix Proteins