title: Examination of an inducible expression system for limiting iron availability during Chlamydia trachomatis infection.
abstract: The obligate intracellular bacterium Chlamydia trachomatis requires iron in order to complete its developmental cycle. Addition of an iron-chelating drug, Desferal (deferoxamine mesylate), to infected cell culture causes Chlamydia to enter persistence. Here, we explore the ability of a stably-transfected cell line with inducible over-expression of the eukaryotic iron efflux protein ferroportin to starve C. trachomatis serovar E for iron. Ferroportin-induced iron removal is perhaps a more direct method of removing iron from the intracellular compartment versus exposure to an exogenous chemical chelator. Following induction, ferroportin-green fluorescent protein (Fpn-GFP) was detected in the plasma membrane, and cells expressing Fpn-GFP remained viable throughout the timescale required for Chlamydia to complete its developmental cycle. Following Fpn-GFP induction in infected cells, chlamydial infectivity remained unchanged, indicating chlamydiae were not in persistence. Ferritin levels indicate only a small decrease in cellular iron following Fpn-GFP expression relative to cultures exposed to Desferal. These data indicate that expression of Fpn-GFP in chlamydiae-infected cells is not capable of reducing iron below the threshold concentration needed to cause chlamydiae to enter persistence.
authors.affiliation: Department of Microbiology, Box 70579, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614-0579, USA. bddill@yahoo.com
authors.forename: Brian D
authors.initials: BD
authors.lastname: Dill
authors.forename: Jane E
authors.initials: JE
authors.lastname: Raulston
mesh_terms: D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002692:Chlamydia trachomatis / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure; D005293:Ferritins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D000098742:Ferroportin
chemical_list: D027682:Cation Transport Proteins; D011994:Recombinant Proteins; D000098742:Ferroportin; D049452:Green Fluorescent Proteins; D005293:Ferritins; D007501:Iron