title: Characterization of a novel mutation in the overlap of tlyA and ppnK involved in capreomycin resistance in Mycobacterium.
abstract: Capreomycin (CAP) is an important second-line drug for multidrug-resistant tuberculosis. To further define the drug resistance mechanism of CAP, a Mycobacterium smegmatis transposon mutant library was constructed using Tn5 transposon for screening isolates with enhanced CAP resistance. A mutant (named C4) with fourfold increased CAP resistance was isolated and characterized. Tn5 was found to be inserted into MSMEG_0841, an annotated pseudogene. However, knockout demonstrated that MSMEG_0841 was not responsible for CAP resistance. We further sequenced the whole genome of C4 and found an A to G substitution in the overlap region between tlyA and ppnK, which leads a stop codon mutation in upstream tlyA and a T2A mutation in downstream ppnK. Mutation in the overlap might confer the dysfuction of both genes. tlyA is a known gene involved in CAP action. Overexpression of ppnK in both Escherichia coli and M. smegmatis confer subtle susceptible to CAP. Taken together, our study found that a novel mutation involved in CAP resistance.
authors.affiliation: State Key Laboratory Breeding Base of Eco-Environment and Bio-Resource of the Three Gorges Area, Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Institute of Modern Biopharmaceuticals, Ministry of Education, School of Life Sciences, Southwest University, Beibei, Chongqing, China.
authors.forename: Qinglin
authors.initials: Q
authors.lastname: Du
authors.forename: Quanxin
authors.initials: Q
authors.lastname: Long
authors.forename: Jinxiao
authors.initials: J
authors.lastname: Mao
authors.forename: Tiwei
authors.initials: T
authors.lastname: Fu
authors.forename: Xiangke
authors.initials: X
authors.lastname: Duan
authors.forename: Jianping
authors.initials: J
authors.lastname: Xie
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D002207:Capreomycin; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D055786:Gene Knockout Techniques; D016680:Genome, Bacterial / Q000235:genetics; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D020125:Mutation, Missense / Q000235:genetics; D009161:Mycobacterium / Q000235:genetics*; D009841:Oligonucleotides / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D009841:Oligonucleotides; C112817:TlyA protein, Mycobacterium tuberculosis; D002207:Capreomycin
keywords: Mycobacterium; capreomycin; ppnK