+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Analysis of transcription of the diphtheria toxin repressor locus in Corynebacterium diphtheriae



Analysis of transcription of the diphtheria toxin repressor locus in Corynebacterium diphtheriae



Abstracts of the General Meeting of the American Society for Microbiology 102: 90-91



The diphtheria toxin repressor (DtxR) inhibits transcription of a subset of C. diphtheriae loci in response to high concentrations of Fe2+. Although the transcription of several DtxR-regulated loci has been studied, the transcript(s) encoding DtxR has(have) not been characterized. We isolated RNA from C. diphtheriae and used reverse transcriptase to generate cDNA. By using polymerase chain reactions, we demonstrated the existence of an RNA transcript that includes both dtxR and the sigma factor gene that is located immediately upstream from dtxR. In addition, we used the RNA isolated from C. diphtheriae in S1 nuclease protection assays to demonstrate the existence of a second dtxR transcript whose 5' end is located approximately 130 basepairs upstream from the dtxR start codon, between the upstream sigma factor gene and dtxR. This second transcript includes dtxR but does not include the upstream sigma factor. We identified a probable -10 sequence located approximately 15 nucleotides upstream of the 5' end of the transcript that encodes dtxR only. We cloned the DNA fragment consisting of the intergenic region between dtxR and the upstream sigma factor gene into a promoter probe vector and tested its promoter activity in E. coli. When this fragment was placed in front of a promoterless lacZ gene, beta-galactisidase activity was detected. Deletion analysis of the cloned C. diphtheriae fragment confirmed the existence of a promoter at approximately 140 baspairs upstream from the dtxR start codon. Our data indicate that there are at least two different mRNA transcripts encoding dtxR and suggest that the amount of DtxR in C. diphtheriae could be regulated at the level of dtxR transcription. Expression of DtxR could also be coordinated under some conditions with expression of the sigma factor gene that is located 225 basepairs upstream from it.

Please choose payment method:






(PDF emailed within 1 workday: $29.90)

Accession: 034404029

Download citation: RISBibTeXText


Related references

Iron dependent regulation of diphtheria toxin and siderophore expression by the cloned corynebacterium diphtheriae repressor gene dtxr in strains of corynebacterium diphtheriae c7. Abstracts of the General Meeting of the American Society for Microbiology 91: 27, 1991

Iron dependent regulation of diphtheria toxin and siderophore expression by the cloned corynebacterium diphtheriae repressor gene dtxr in corynebacterium diphtheriae c7 strains. Infection & Immunity 59(6): 1899-1904, 1991

Analysis of amino acid substitutions within the third domain of the diphtheria toxin repressor of Corynebacterium diphtheriae that affect repressor activity. Abstracts of the General Meeting of the American Society for Microbiology 101: 135, 2001

Characterization of a defective diphtheria toxin repressor (dtxR) allele and analysis of dtxR transcription in wild-type and mutant strains of Corynebacterium diphtheriae. Infection and Immunity 59(11): 3903-3908, 1991

Evidence for direct regulation of diphtheria toxin gene transcription by an Fe2+-dependent DNA-binding repressor, DtoxR, in Corynebacterium diphtheriae. Infection and Immunity 57(10): 3221-3225, 1989

Evidence for direct regulation of diphtheria toxin gene transcription by an iron dependent dna binding repressor d tox r in corynebacterium diphtheriae. Infection & Immunity 57(10): 3221-3225, 1989

Analysis of the two promoter/operators from Corynebacterium diphtheriae that are regulated by the diphtheria toxin repressor and iron. Abstracts of the General Meeting of the American Society for Microbiology 94: 127, 1994

Iron-dependent regulation of diphtheria toxin and siderophore expression by the cloned Corynebacterium diphtheriae repressor gene dtxR in C. diphtheriae C7 strains. Infection and Immunity 59(6): 1899-1904, 1991

Cloning, sequence, and footprint analysis of two promoter/operators from Corynebacterium diphtheriae that are regulated by the diphtheria toxin repressor (DtxR) and iron. Journal of Bacteriology 176(4): 1141-1149, 1994

Calorimetric studies of diphtheria toxin repressor from Corynebacterium diphtheriae. Biophysical Journal 72(2 Part 2): A416, 1997

Point mutations in tox promoter/operator and diphtheria toxin repressor (DTXR) gene associated with the level of toxin production by Corynebacterium diphtheriae strains isolated in Belarus. Molekuliarnaia Genetika Mikrobiologiia i Virusologiia 2007(1): 22-29, 2007

Point mutations in tox promoter/operator and diphtheria toxin repressor (Delta txr) gene associated with the level of toxin production by Corynebacterium diphtheriae strains isolated in Belarus. Molekulyarnaya Genetika Mikrobiologiya i Virusologiya (1): 22-29, 2007

New diphtheria toxin repressor types depicted in a Romanian collection of Corynebacterium diphtheriae isolates. Journal of Basic Microbiology 54(10): 1136-1139, 2014

Transposon mutagenesis in Corynebacterium diphtheriae and isolation of a knockout of the diphtheria toxin repressor gene. Abstracts of the General Meeting of the American Society for Microbiology 101: 62, 2001