title: Inducible expression of transmembrane proteins on bacterial magnetic particles in Magnetospirillum magneticum AMB-1.
abstract: Bacterial magnetic particles (BacMPs) produced by the magnetotactic bacterium Magnetospirillum magneticum AMB-1 are used for a variety of biomedical applications. In particular, the lipid bilayer surrounding BacMPs has been reported to be amenable to the insertion of recombinant transmembrane proteins; however, the display of transmembrane proteins in BacMP membranes remains a technical challenge due to the cytotoxic effects of the proteins when they are overexpressed in bacterial cells. In this study, a tetracycline-inducible expression system was developed to display transmembrane proteins on BacMPs. The expression and localization of the target proteins were confirmed using luciferase and green fluorescent protein as reporter proteins. Gene expression was suppressed in the absence of anhydrotetracycline, and the level of protein expression could be controlled by modulating the concentration of the inducer molecule. This system was implemented to obtain the expression of the tetraspanin CD81. The truncated form of CD81 including the ligand binding site was successfully displayed at the surface of BacMPs by using Mms13 as an anchor protein and was shown to bind the hepatitis C virus envelope protein E2. These results suggest that the tetracycline-inducible expression system described here will be a useful tool for the expression and display of transmembrane proteins in the membranes of BacMPs.
authors.affiliation: Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan. y-tomoko@cc.tuat.ac.jp
authors.forename: Tomoko
authors.initials: T
authors.lastname: Yoshino
authors.forename: Akiko
authors.initials: A
authors.lastname: Shimojo
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Maeda
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics*; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D017930:Genes, Reporter; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D008051:Lipid Bilayers; D008280:Magnetics; D055944:Magnetosomes / Q000378:metabolism; D042201:Magnetospirillum / Q000235:genetics* / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics*; D010957:Plasmids / Q000235:genetics; D015202:Protein Engineering; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D013752:Tetracycline / Q000494:pharmacology; D060225:Tetraspanin 28; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D001426:Bacterial Proteins; D017931:DNA Primers; D008051:Lipid Bilayers; D008565:Membrane Proteins; D011994:Recombinant Proteins; D060225:Tetraspanin 28; D014759:Viral Envelope Proteins; D049452:Green Fluorescent Proteins; C091015:glycoprotein E2, Hepatitis C virus; D013752:Tetracycline