Genome-Modified Silkworms for Natural Chimeric Silk Thread Spinning
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Solution Overview
Problem
The challenge lies in producing a chimeric silk thread with properties similar to bagworm silk thread using a silkworm, as existing methods using transposon technology for gene insertion in silkworms result in low expression efficiency, and conventional spinning technologies struggle to fiberize bagworm fibroin protein effectively.
Innovation Solution
Employing a genome-editing technology using TAL-PITCh method to knock-in a modified fibroin gene into silkworms, combining a Left-TALEN and Right-TALEN expression vectors with a donor vector to insert a bagworm fibroin gene, resulting in a silkworm that produces a chimeric fibroin protein with enhanced properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transposon technology is used to insert fibroin gene into silkworm, then gene insertion is achieved, but expression efficiency is low
Solution Approach 1:
The patent changes the method parameter from transposon-based insertion to CRISPR/Cas9-mediated homology-directed repair. This parameter change enables precise knock-in of the bagworm fibroin gene into the silkworm genome at specific loci, achieving high expression efficiency (over 80% of silk gland protein is chimeric fibroin) while maintaining ease of manufacture through established genome editing protocols
2Productivity
If bagworm fibroin protein is produced in host using genetic recombination, then mass production is enabled, but the protein is liquid and requires processing into fibrous form
Solution Approach 1:
The patent copies the natural silk spinning system by expressing the bagworm fibroin gene in silkworms, which then spin the chimeric fibroin protein into fibrous form naturally. This eliminates the need for separate fiber processing steps required when producing recombinant protein in conventional hosts, as the silkworm itself performs the fiber formation function
Solution Approach 2:
The silkworm system provides self-service by automatically converting the produced chimeric fibroin protein into fibrous form through its native spinning mechanism. The silkworm larvae spin the protein into cocoon fibers, eliminating the need for external processing equipment and labor-intensive fiberization steps
3Ease of manufacture
If conventional spinning technology is used on bagworm fibroin protein, then spinning is attempted, but it is difficult to fiberize the protein
Solution Approach 1:
The patent copies the successful natural spinning system of silkworms and applies it to produce chimeric fibroin. By expressing the bagworm fibroin gene in silkworms, the protein is produced in the correct biological context for natural spinning, ensuring reliable fiberization without requiring development of new spinning technologies
4Productivity
If cloned fibroin gene is introduced into host, then recombinant bagworm fibroin protein can be mass-produced, but the full-length genome sequence has not been determined sufficiently
Solution Approach 1:
The patent performs preliminary action by synthesizing the complete bagworm fibroin H chain gene sequence based on available partial sequences and protein structure knowledge. This synthesized gene is then introduced into silkworms, enabling precise production of the full-length chimeric protein without requiring complete prior sequencing of the bagworm genome
Data Source
AI summary
A silkworm that can produce a chimeric silk thread in fibrous form with physical properties which approximate those of the bagworm silk thread is provided. A genome-modified silkworm is also provided in which a gene encoding a modified bagworm fibroin protein is inserted, wherein the gene is obtained by fusing a gene fragment encoding a bagworm-derived fibroin protein and a gene fragment encoding a silkworm-derived fibroin protein.