title: Modifying the Mechanical Properties of Silk Fiber by Genetically Disrupting the Ionic Environment for Silk Formation.
abstract: Silks are widely used biomaterials, but there are still weaknesses in their mechanical properties. Here we report a method for improving the silk fiber mechanical properties by genetic disruption of the ionic environment for silk fiber formation. An anterior silk gland (ASG) specific promoter was identified and used for overexpressing ion-transporting protein in the ASG of silkworm. After isolation of the transgenic silkworms, we found that the metal ion content, conformation and mechanical properties of transgenic silk fibers changed accordingly. Notably, overexpressing endoplasmic reticulum Ca2+-ATPase in ASG decreased the calcium content of silks. As a consequence, silk fibers had more α-helix and β-sheet conformations, and their tenacity and extension increased significantly. These findings represent the in vivo demonstration of a correlation between metal ion content in the spinning duct and the mechanical properties of silk fibers, thus providing a novel method for modifying silk fiber properties.
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University , 216 Tiansheng Road, Chongqing 400716, P. R. China.
authors: Xin
authors: X
authors: Wang
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University , 216 Tiansheng Road, Chongqing 400716, P. R. China.
authors: Ping
authors: P
authors: Zhao
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University , 216 Tiansheng Road, Chongqing 400716, P. R. China.
authors: Yi
authors: Y
authors: Li
authors: Animal Center, Chongqing Medical University , 1 Yixuanyuan Road, Chongqing 400016, P. R. China.
authors: Qiying
authors: Q
authors: Yi
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University , 216 Tiansheng Road, Chongqing 400716, P. R. China.
authors: Sanyuan
authors: S
authors: Ma
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University , 216 Tiansheng Road, Chongqing 400716, P. R. China.
authors: Kang
authors: K
authors: Xie
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University , 216 Tiansheng Road, Chongqing 400716, P. R. China.
authors: Huifang
authors: H
authors: Chen
authors: State Key Laboratory of Silkworm Genome Biology, Southwest University , 216 Tiansheng Road, Chongqing 400716, P. R. China.
authors: Qingyou
authors: Q
authors: Xia
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D012831:Bombyx / Q000235:genetics; D020869:Gene Expression Profiling; D007477:Ions / Q000032:analysis*; D047011:Silk / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D007477:Ions; D047011:Silk