title: Characterisation of a putative AraC transcriptional regulator from Mycobacterium smegmatis.
abstract: MSMEG_0307 is annotated as a transcriptional regulator belonging to the AraC protein family and is located adjacent to the arylamine N-acetyltransferase (nat) gene in Mycobacterium smegmatis, in a gene cluster, conserved in most environmental mycobacterial species. In order to elucidate the function of the AraC protein from the nat operon in M. smegmatis, two conserved palindromic DNA motifs were identified using bioinformatics and tested for protein binding using electrophoretic mobility shift assays with a recombinant form of the AraC protein. We identified the formation of a DNA:AraC protein complex with one of the motifs as well as the presence of this motif in 20 loci across the whole genome of M. smegmatis, supporting the existence of an AraC controlled regulon. To characterise the effects of AraC in the regulation of the nat operon genes, as well as to gain further insight into its function, we generated a ΔaraC mutant strain where the araC gene was replaced by a hygromycin resistance marker. The level of expression of the nat and MSMEG_0308 genes was down-regulated in the ΔaraC strain when compared to the wild type strain indicating an activator effect of the AraC protein on the expression of the nat operon genes.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Evangelopoulos
authors.forename: Antima
authors.initials: A
authors.lastname: Gupta
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Lack
authors.forename: Arundhati
authors.initials: A
authors.lastname: Maitra
authors.forename: Annemieke M C
authors.initials: AM
authors.lastname: ten Bokum
authors.forename: Sharon
authors.initials: S
authors.lastname: Kendall
authors.forename: Edith
authors.initials: E
authors.lastname: Sim
authors.forename: Sanjib
authors.initials: S
authors.lastname: Bhakta
mesh_terms: D000904:Antibiotics, Antitubercular / Q000494:pharmacology; D051777:AraC Transcription Factor / Q000235:genetics*; D001191:Arylamine N-Acetyltransferase / Q000235:genetics; D001483:Base Sequence; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D008969:Molecular Sequence Data; D020102:Mycobacterium smegmatis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D009169:Mycobacterium tuberculosis / Q000235:genetics; D059372:Nucleotide Motifs / Q000235:genetics; D009876:Operon / Q000235:genetics; D011485:Protein Binding / Q000235:genetics
chemical_list: D000904:Antibiotics, Antitubercular; D051777:AraC Transcription Factor; D001191:Arylamine N-Acetyltransferase