title: New diphtheria toxin repressor types depicted in a Romanian collection of Corynebacterium diphtheriae isolates.
abstract: Corynebacterium diphtheriae is the etiological agent of diphtheria, a potential fatal disease caused by a corynephage toxin. The expression of this diphtheria toxin is controlled via an iron-dependent repressor with various functions (DtxR). Some mutations in the dtxR gene are associated with diminished activity or even with total loss of DtxR function. We conducted a molecular study to characterize the dtxR alleles harbored by 34 isolates of C. diphtheriae recovered from Romanian patients between 1961 and 2007. Three of the seven alleles identified in this study have not previously been described. Two new DtxR types were identified, one of which has an unusual polypeptide length. All the new DtxR types were found in toxigenic isolates, suggesting that they effectively regulate the expression of diphtheria toxin. Furthermore, one of the new DtxR identified was also found in a non-toxigenic isolate, making it a potential source of toxigenic isolates after lysogenic conversion.
authors.affiliation: "Cantacuzino" National Institute of Research and Development for Microbiology and Immunology, Molecular Epidemiology Laboratory, Bucharest, Romania.
authors.forename: Sorin
authors.initials: S
authors.lastname: Dinu
authors.forename: Maria
authors.initials: M
authors.lastname: Damian
authors.forename: Edgar
authors.initials: E
authors.lastname: Badell
authors.forename: Cristiana Cerasella
authors.initials: CC
authors.lastname: Dragomirescu
authors.forename: Nicole
authors.initials: N
authors.lastname: Guiso
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003353:Corynebacterium diphtheriae / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004165:Diphtheria / Q000382:microbiology; D004167:Diphtheria Toxin / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008969:Molecular Sequence Data; D012383:Romania
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D004167:Diphtheria Toxin; C075586:DtxR protein, Corynebacterium diphtheriae
keywords: Alleles; Mutations; Protein variants