title: Allopatric integrations selectively change host transcriptomes, leading to varied expression efficiencies of exotic genes in Myxococcus xanthus.
abstract: BACKGROUND
  Exotic genes, especially clustered multiple-genes for a complex pathway, are normally integrated into chromosome for heterologous expression. The influences of insertion sites on heterologous expression and allotropic expressions of exotic genes on host remain mostly unclear.
  
  
  RESULTS
  We compared the integration and expression efficiencies of single and multiple exotic genes that were inserted into Myxococcus xanthus genome by transposition and attB-site-directed recombination. While the site-directed integration had a rather stable chloramphenicol acetyl transferase (CAT) activity, the transposition produced varied CAT enzyme activities. We attempted to integrate the 56-kb gene cluster for the biosynthesis of antitumor polyketides epothilones into M. xanthus genome by site-direction but failed, which was determined to be due to the insertion size limitation at the attB site. The transposition technique produced many recombinants with varied production capabilities of epothilones, which, however, were not paralleled to the transcriptional characteristics of the local sites where the genes were integrated. Comparative transcriptomics analysis demonstrated that the allopatric integrations caused selective changes of host transcriptomes, leading to varied expressions of epothilone genes in different mutants.
  
  
  CONCLUSIONS
  With the increase of insertion fragment size, transposition is a more practicable integration method for the expression of exotic genes. Allopatric integrations selectively change host transcriptomes, which lead to varied expression efficiencies of exotic genes.
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. zhuliping1986@163.com.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. xinjing92@126.com.
authors.forename: Xin-Jing
authors.initials: XJ
authors.lastname: Yue
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. hk_sdu@126.com.
authors.forename: Kui
authors.initials: K
authors.lastname: Han
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. lizhifeng@sdu.edu.cn.
authors.forename: Zhi-Feng
authors.initials: ZF
authors.lastname: Li
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. jnsdzls@163.com.
authors.forename: Lian-Shuai
authors.initials: LS
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. yixiunan@vip.qq.com.
authors.forename: Xiu-Nan
authors.initials: XN
authors.lastname: Yi
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. hlw1225@hotmail.com.
authors.forename: Hai-Long
authors.initials: HL
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. zhangyouming@sdu.edu.cn.
authors.forename: You-Ming
authors.initials: YM
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Jinan, 250100, China. lilab@sdu.edu.cn.
authors.forename: Yue-Zhong
authors.initials: YZ
authors.lastname: Li
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D034261:Epothilones / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D016254:Mutagenesis, Insertional; D016941:Myxococcus xanthus / Q000235:genetics* / Q000378:metabolism; D059467:Transcriptome
chemical_list: D001426:Bacterial Proteins; D034261:Epothilones