Researcher: Let the silkworm "spit" the spider silk

The Tan Anjiang Research Group of the Center for Excellence in Molecular Plant Science of the Chinese Academy of Sciences (Institute of Plant Physiology and Ecology) used gene-site replacement methods to express spider silk proteins in silk gland and silkworm pupa. Recently, relevant research results were published online in the US National Academy of Sciences.

Spider silk is the natural protein fiber with the best mechanical properties in nature. Its strength is even higher than that of Kevlar fiber for making bulletproof vests. It has broad application prospects in industry, medical and national defense. However, how to obtain a large amount of spider silk fiber has been difficult to solve. Because silk fibroin and spider silk protein have certain similarities in structure, it is a feasible strategy to use the silkworm genetic transformation to obtain a large number of spider silk fibers.

The Tan Anjiang research team used the genome editing tool to transcribe the activator-like effector nuclease, completely knocking out the coding region of the silk fibroin heavy chain gene, while retaining the complete regulatory sequences upstream and downstream of the coding region. On this basis, the DNA fragment containing part of the spider silk gene and fluorescent marker was integrated and integrated, and the expression of the endogenous silk fibroin heavy chain gene was completely removed. The endogenous regulatory sequence of the silk fibroin heavy chain gene was used. Regulate the expression of exogenous spider silk genes. The expression of spider silk protein was detected in silk gland and silkworm pupa of transformed individuals, and its content was up to 35.2% in pure and individual sputum layer, which was much higher than the reported transgenic method.

The system expands the application of the silk gland bioreactor and provides a new strategy for the mass production of new fiber materials and the expression of other high value-added proteins.