title: Molecular cloning, gene expression analysis, and recombinant protein expression of novel silk proteins from larvae of a retreat-maker caddisfly, Stenopsyche marmorata.
abstract: Retreat-maker larvae of Stenopsyche marmorata, one of the major caddisfly species in Japan, produce silk threads and adhesives to build food capture nets and protective nests in water. Research on these underwater adhesive silk proteins potentially leads to the development of new functional biofiber materials. Recently, we identified four major S. marmorata silk proteins (Smsps), Smsp-1, Smsp-2, Smsp-3, and Smsp-4 from silk glands of S. marmorata larvae. In this study, we cloned full-length cDNAs of Smsp-2, Smsp-3, and Smsp-4 from the cDNA library of the S. marmorata silk glands to reveal the primary sequences of Smsps. Homology search results of the deduced amino acid sequences indicate that Smsp-2 and Smsp-4 are novel proteins. The Smsp-2 sequence [167 amino acids (aa)] has an array of GYD-rich repeat motifs and two (SX)4E motifs. The Smsp-4 sequence (132 aa) contains a number of GW-rich repeat motifs and three (SX)4E motifs. The Smsp-3 sequence (248 aa) exhibits high homology with fibroin light chain of other caddisflies. Gene expression analysis of Smsps by real-time PCR suggested that the gene expression of Smsp-1 and Smsp-3 was relatively stable throughout the year, whereas that of Smsp-2 and Smsp-4 varied seasonally. Furthermore, Smsps recombinant protein expression was successfully performed in Escherichia coli. The study provides new molecular insights into caddisfly aquatic silk and its potential for future applications.
authors.affiliation: Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Xue
authors.initials: X
authors.lastname: Bai
authors.affiliation: Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Mayo
authors.initials: M
authors.lastname: Sakaguchi
authors.affiliation: Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Yamaguchi
authors.affiliation: Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Shiori
authors.initials: S
authors.lastname: Ishihara
authors.affiliation: Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Masuhiro
authors.initials: M
authors.lastname: Tsukada
authors.affiliation: Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan; Institute of Mountain Science, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Minamiminowa, Nagano 399-4598, Japan.
authors.forename: Kimio
authors.initials: K
authors.lastname: Hirabayashi
authors.affiliation: Institute for Fiber Engineering, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Kousaku
authors.initials: K
authors.lastname: Ohkawa
authors.affiliation: Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan.
authors.forename: Takaomi
authors.initials: T
authors.lastname: Nomura
authors.affiliation: Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, Ueda, Nagano 386-8567, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Matsumoto, Nagano 390-8621, Japan. Electronic address: rarai@shinshu-u.ac.jp.
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Arai
mesh_terms: D020087:Alu Elements; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004926:Escherichia coli / Q000235:genetics; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism*; D007313:Insecta / Q000235:genetics* / Q000502:physiology; D007814:Larva / Q000235:genetics; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012621:Seasons; D047011:Silk / Q000235:genetics*
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D011994:Recombinant Proteins; D047011:Silk
keywords: Aquatic silk; Caddisfly; Silk protein; Smsp; Stenopsyche marmorata; Trichoptera