title: Cloning and characterization of the shell matrix protein Shematrin in scallop Chlamys farreri.
abstract: The Shematrin family is unique to the organic matrices of pearl oyster shells, containing repetitive, low-complexity domains designated as XGnX (where X is a hydrophobic amino acid). Current studies suggested that Shematrins are framework proteins in the prismatic layer of Pinctada fucata; however, the exact function of Shematrin during shell formation is unclear. In this study, we cloned and characterized Shematrin, a protein highly homologous to Shematrin-2, from the mantle tissue of scallop (Chlamys farreri). Semi-quantitative reverse transcript polymerase chain reaction analysis showed that Shematrin is exclusively expressed in the mantle. Knocking down the expression of Shematrin in adult scallops via double-stranded RNA injection led to an abnormal folia surface. After the shell was notched, the expression level of Shematrin remarkably increased and then gradually decreased, suggesting that Shematrin is critically involved in the shell repair progress. Injection of Shematrin double-stranded RNA reduced the speed of shell regeneration and caused abnormal surface morphology of the regenerated shell. The RNA interference and shell notching experiments indicated that Shematrin plays a key role in the folia formation of C. farreri. Structure prediction showed that Shematrin may be an intrinsically disordered protein, with high flexibility and elasticity of the molecular conformation, which facilitate binding multiple protein partners. Based on the structure features, we hypothesized that Shematrin may participate in framework organization via binding with several specific acidic proteins, functioning as a molecular hub in the protein interaction networks.
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Ya
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Ganchu
authors.initials: G
authors.lastname: Jia
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Guangrui
authors.initials: G
authors.lastname: Xu
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Jingtan
authors.initials: J
authors.lastname: Su
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing 100084, China lpxie@mail.tsinghua.edu.cn.
authors.forename: Liping
authors.initials: L
authors.lastname: Xie
authors.affiliation: Key Laboratory of Marine Genetics and Breeding (MGB), Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Hu
authors.affiliation: Institute of Marine Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China Protein Science Laboratory of the Ministry of Education, Tsinghua University, Beijing 100084, China.
authors.forename: Rongqing
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D049897:Pectinidae; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000737:chemistry / Q000235:genetics*; D034622:RNA Interference; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D017931:DNA Primers; D011506:Proteins
keywords: Chlamys farreri; Shematrin; folia; framework; shell