Fig 1.
The calcium binding protein sequence and transgenic experiment vector.
One copy of the sequence [(AGSGAG)6ASEYDYDDDSDDDDEWD]2 (A). (AGSGAG)n is the silk fibroin repetitive domain from B. mori. The calcium-binding protein sequence from the shell nacreous matrix protein MSI60 is marked by a black line. The vector used for the transgenic experiment (B). ITR, inverted terminal repeats of PB transposon; FL, fibroin light chain; FLSP, signal peptide of fibroin light chain; CABP, calcium-binding protein; A3, Bombyx mori A3 cytoplasmic actin gene; EGFP, enhanced green fluorescence protein; SV40, 3’-untranslated sequences.
Fig 2.
G1 transgenic silkworms positive for EGFP.
Transformed larvae are fluorescent compared with non-transformed controls. The transgenic silkworm under fluorescence (A) and visible light (B). The native silkworm Lan 10 under fluorescence (C) and visible light (D).
Table 1.
The efficiency of the transgenic experiment.
Fig 3.
Western blot analysis of cocoon silk.
The SDS-PAGE identification of cocoon silk from 17 transgenic families (A) and their corresponding western blot results (B). The antibody was diluted to 1: 2000. The protein marker is shown at the left of the figure as M; Ct: Control strain Lan 10; SCa1-SCa17: transgenic family. A, B, C indicate three protein bands with different molecular weights. The corresponding bands were cut out for MS/MS identification.
Fig 4.
The Ca-binding activity measurement of the fibroin solution.
Black line, CaCl2 control (A), red line, natural silk (B), green line, transgenic silkworm SCa3 (C), blue line, transgenic silkworm SCa8 (D), light blue line, transgenic silkworm SCa10 (E).
Fig 5.
The detection of the mechanical properties of composite silk fibers.
(A) The measurement of the load (N) of the transgenic silk. (B) The measurement of the relative tensile modulus.
Fig 6.
The measurement of the thermal characteristics of the transgenic silk.
The exothermic peaks of Sca3, Sca8 and Sca10 appear at 314, 314 and 303°C, respectively.