Colored Fluorescent Silk Made by Transgenic Silkworms

Abstract

Silk is a protein fiber used to weave fabrics and as a biomaterial in medical applications. Recently, genetically modified silks have been produced from transgenic silkworms. In the present study, transgenic silkworms for the mass production of three colors of fluorescent silks, (green, red, and orange) are generated using a vector originating from the fibroin H chain gene and a classical breeding method. The suitability of the recombinant silks for making fabrics is investigated by harvesting large amounts of the cocoons, obtained from rearing over 20 thousand silkworms. The application of low temperature and a weakly alkaline solution for cooking and reeling enables the production of silk fiber without loss of color. The maximum strain tolerated and Young's modulus of the fluorescent silks are similar to those of ordinary silk, although the maximum stress value of the recombinant silk is slightly lower than that of the control. Fabrics with fluorescent color are demonstrated using the recombinant silk, with the color persisting for over two years. The results indicate that large amounts of genetically modified silk can be made by transgenic silkworms, and the silk is applicable as functional silk fiber for making fabrics and for use in medical applications.

Advanced silk material spun by a transgenic silkworm promotes cell proliferation for biomedical application

“…The presence of recombinant hFGF1 in the sericin layer of the hSFSV raw silk might cause the slight alterations found in the diameter and mechanical properties thereof. Similar results, where the presence of foreign fluorescent proteins in the fibroin or sericin layer of silkworm silk altered the mechanical properties of the silk fiber, were observed in previous studies [30,48].…”

“…For example, a modified chimeric silkworm/spider recombinant silk spun by transgenic silkworms using a fib-H promoter-derived transgenic construct was reported to be significantly tougher than ordinary silkworm fiber [29]. A colored fluorescent silk was made for textile application by fusion expression of three different fluorescent proteins with fibroin using fib-H promoter-originated transgenic vectors [30]. A fibroin solution-based material in which is contained a fusion protein of fibroin L chain and human basic fibroblast growth factor (bFGF) was reported to be biologically active as a new biomaterial for tissue engineering after refolding by the glutathione redox system [31].…”

Introduction of VEGF or RGD sequences improves revascularization properties of Bombyx mori silk fibroin produced by transgenic silkworm

“…32 To introduce the RGD tripeptide into H-fibroin, the DNA fragment coding [TGRGDSPAS] 8 peptide 21 was cloned into the H-fibroin fusion vector. 36 The wild type B. mori SF without improving silk character (WT SF) was used for a comparison of TG SF. 36 The TG silkworms were established using a non-diapausing strain, w1-pnd, and were mated with the diapausing strain, w1, to maintain the TG silkworms as diapausing strains.…”

Targeted glycoengineering extends the protein N-glycosylation pathway in the silkworm silk gland

“…But, the baculovirus-infected silkworm is a binary and transient recombinant protein production system. Thus, various investigators began to genetically transform silkworms with DNA constructs encoding the protein of interest under the transcriptional control of either whole body (Tamura et al, 2000) or silk gland-specific promoters (Adachi et al, 2006; Hino et al, 2006; Iizuka et al, 2009; Iizuka et al, 2013; Kojima et al, 2007; Kurihara et al, 2007; Kuwana et al, 2014; Long et al, 2015; Ogawa et al, 2007; Royer et al, 2005; Seong et al, 2011; Teule et al, 2012; Tomita et al, 2007; Tomita et al, 2003; Wang et al, 2014; Wen et al, 2010; Xu, 2014; Yanagisawa et al, 2007; reviewed in Tomita, 2011). This new, single component approach provided a stable, rather than transient source of recombinant proteins.…”