title: An insight into the regulation of mce4 operon of Mycobacterium tuberculosis.
abstract: The mce4 operon is reported to be involved in cholesterol utilization and intracellular survival of Mycobacterium tuberculosis (M. tuberculosis). The regulatory mechanism of this important operon was unknown so far. Here we report detection of the promoter region and regulatory factors of the mce4 operon. The in silico analyzed putative promoter region was cloned in promoter selection vector and promoter strength was measured by O-Nitrophenyl-β-D-galactopyranosidase (ONPG) assay. The transcription start site was determined by 5' Rapid amplification of C terminal end (5'RACE). Surface stress, hypoxia and presence of cholesterol, were found to be stimulatory for mce4 operon promoter induction. Pull down assay coupled with 2D gel electrophoresis resolved many proteins; few prominent spots were processed for identification. MALDI TOF-TOF identified proteins of M. tuberculosis which supported the regulatory function of the identified promoter region and cholesterol utilization of mce4 operon. Since mce4 operon is involved in cholesterol utilization and intracellular survival of M. tuberculosis in the later phase of infection, identification of the promoter sequence as reported in the present communication may facilitate development of effective inhibitors to regulate expression of mce4 operon which may prove to be a good drug target to prevent latency in tuberculosis.
authors.affiliation: Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi 110007, India. microknp@gmail.com
authors.forename: Nisha
authors.initials: N
authors.lastname: Rathor
authors.forename: Amita
authors.initials: A
authors.lastname: Chandolia
authors.forename: Neeraj Kumar
authors.initials: NK
authors.lastname: Saini
authors.forename: Rajesh
authors.initials: R
authors.lastname: Sinha
authors.forename: Rakesh
authors.initials: R
authors.lastname: Pathak
authors.forename: Kushal
authors.initials: K
authors.lastname: Garima
authors.forename: Satendra
authors.initials: S
authors.lastname: Singh
authors.forename: Mandira
authors.initials: M
authors.lastname: Varma-Basil
authors.forename: Mridula
authors.initials: M
authors.lastname: Bose
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D002784:Cholesterol / Q000378:metabolism / Q000494:pharmacology; D003198:Computer Simulation; D004268:DNA-Binding Proteins / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity; D009876:Operon / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D013312:Stress, Physiological / Q000235:genetics; D024363:Transcription Initiation Site; D014774:Virulence / Q000235:genetics; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C510664:Mce4A protein, Mycobacterium tuberculosis; D002784:Cholesterol; D001616:beta-Galactosidase