title: Remobilizing deleted piggyBac vector post-integration for transgene stability in silkworm.
abstract: Deletion of transposable elements post-genomic integration holds great promise for stability of the transgene in the host genome and has an essential role for the practical application of transgenic animals. In this study, a modified piggyBac vector that mediated deletion of the transposon sequence post-integration for transgene stability in the economically important silkworm Bombyx mori was constructed. The piggyBac vector architecture contains inversed terminal repeat sequences L1, L2 and R1, which can form L1/R1 and L2/R1 types of transposition cassettes. hsp70-PIG as the piggyBac transposase expression cassette for initial transposition, further remobilization and transgene stabilization test was transiently expressed in a helper vector or integrated into the modified vector to produce a transgenic silkworm. Shortening L2 increased the transformation frequency of L1/R1 into the silkworm genome compared to L2/R1. After the integration of L1/R1 into the genome, the remobilization of L2/R1 impaired the transposon structure and the resulting transgene linked with an impaired transposon was stable in the genome even in the presence of exogenously introduced transposase, whereas those flanked by the intact transposon were highly mobile in the genome. Our results demonstrated the feasibility of post-integration deletion of transposable elements to guarantee true transgene stabilization in silkworm. We suggest that the modified vector will be a useful resource for studies of transgenic silkworms and other piggyBac-transformed organisms.
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Tiansheng Road 216, Beibei, Chongqing, 400715, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Riyuan
authors.initials: R
authors.lastname: Wang
authors.forename: Yuancheng
authors.initials: Y
authors.lastname: Wang
authors.forename: Hanfu
authors.initials: H
authors.lastname: Xu
authors.forename: Lin
authors.initials: L
authors.lastname: Yuan
authors.forename: Huan
authors.initials: H
authors.lastname: Ding
authors.forename: Sanyuan
authors.initials: S
authors.lastname: Ma
authors.forename: You
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ping
authors.initials: P
authors.lastname: Zhao
authors.forename: Qingyou
authors.initials: Q
authors.lastname: Xia
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics*; D012831:Bombyx / Q000166:cytology / Q000235:genetics*; D004251:DNA Transposable Elements / Q000235:genetics*; D017353:Gene Deletion; D017930:Genes, Reporter; D005822:Genetic Vectors / Q000235:genetics*; D042822:Genomic Instability / Q000235:genetics*; D016297:Mutagenesis, Site-Directed; D020079:Terminal Repeat Sequences / Q000235:genetics; D019076:Transgenes / Q000235:genetics; D019895:Transposases / Q000235:genetics
chemical_list: D004251:DNA Transposable Elements; D019895:Transposases