Characterization of a novel repetitive secretory protein specifically expressed in the modified salivary gland of Hydropsyche sp. (Trichoptera; Hydropsychidae)

• Published in: Insect biochemistry and molecular biology Vol. 35; no. 5; pp. 435 - 441
• Main Authors: Eum, Jai-Hoon, Yoe, Sung-Moon, Seo, Young-R, Kang, Seok-Woo, Han, Sung-Sik
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2005
• Subjects: amino acid sequences; Animals; aquatic insects; Base Sequence; complementary DNA; Expressed sequence tags; gene expression; Hydropsyche; Hydropsychidae; insect proteins; Insect Proteins - biosynthesis; Insect Proteins - genetics; Insecta - genetics; Insecta - metabolism; messenger RNA; Modified salivary gland; Molecular Sequence Data; nest forming protein-1; Nf-1 protein (Nest forming protein-1); nucleotide sequences; protein secretion; Repetitive amino acid; repetitive sequences; salivary glands; Salivary Glands - metabolism; silk; silk glands; Trichoptera; Trichoptera Hydropsyche sp; Modified salivary gland; Repetitive amino acid; Nf-1 protein (Nest forming protein-1); Trichoptera Hydropsyche sp; Expressed sequence tags
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2005.01.009

Here, we report the cloning and characterization of a common salivary gland-specific gene, Nf-1, from late instar Hydropsyche sp. larvae, and show that the corresponding gene product is translated in the gland and secreted to the gland lumen. The deduced Nf-1 protein is primarily composed of five repetitive sequence units of 63–65 amino acids, and contains a putative signal sequence composed of 19 amino acids. Secreted Nf-1 (∼37 kDa) was localized to the gland lumen by Western blotting of gland and lumen fractions. Together, the structure, expression pattern and protein localization of Nf-1 indicate that this protein is likely to be a major component of the silk shields and nets produced by the aquatic insect, Trichoptera.