| Spider silk is one of the best natural fiber with excellent mechanical properties,however,due to the behavior of vision of the spider bite and territory consciousness,we cannot get spider silk by large-scale breeding.Silkworm has a spinning system which similar with that of spider,and the transgenic technology on Bombyx mori is ordinary to operate,boasting as an ideal reactor for producing spider silk.In this study,piggyBac transposable technique was used to achieve the specific expression of three spider silk genes in the posterior silk glands of silkworms,these are 2 repeats of Argiope argentata pyriform spidroin 1(named as 2x PySpl-A.arg,about 1.4kb)、2 repeats of Nephila clavipes pyriform spidroin 2(named as 2x PySp2.-N.cla,about 1.4kb)and 1 repeat of Nephila clavipes aggregate spider glue 1(named as 1x ASG1-N.cla,about 1.2kb)respectively,and three recombinant spider silk fibers were obtained,named as PA、PN and ASG1 lineages respectively.The results showed that the mRNA relative expression level of spider silk protein was remarkably consistent with that of cocoon protein content.And the higher the content of spidr silk protein,the better the effect of improving the mechanical properties of silk fibers.Additiontionally,in three kinds of spider silk genes,the 2x PySpl-A.arg genes can effectively improve the mechanical properties of silk fiber:the maximum stress was increased by 36.89%and the toughness was enhanced up to 175.51%;The effect of exogenous 1x ASG1-N.cla gene on silk performance was the next best,with the maximum stress increased by 34.20%and toughness increased by 82.34%,while the 2x PySp2-N.cla gene have no obvious improvement on the properties of silk.Additionally,this study also provides a basis for the improvement of the mechanical properties of silk by spider silk gene. |
