scholarly journals In silico mutational analysis in RNA polymerase β subunit (rpoB) gene of rifampicin-resistant in Mycobacterium tuberculosis from Malaysia

2021 ◽  
pp. 47-58
Author(s):  
Ernie Zuraida Ali ◽  
Nurul Hamizah Hamidon ◽  
Rahizan Issa
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Rna Polymerase ◽  
Protein Interactions ◽  
Mutational Analysis ◽  
Public Health Problem ◽  
Rpob Gene ◽  
Drug Susceptibility ◽  
Β Subunit ◽  
Mutant Proteins ◽  
Information Sequence

Tuberculosis (TB) is mainly caused by Mycobacterium tuberculosis (MTB) and remains as a key public health problem worldwide. Most of MTB clinical strains are resistant to rifampicin (RIF), the first-line anti-tuberculosis drug. RIF resistance to MTB is due to mutations that mainly found in RIF resistance-determining region (RRDR) in drug target gene, RNA polymerase β subunit (rpoB). Therefore, the aim of the study is to extend the identification of variants in rpoB gene and to elucidate the effect of variants to the RIF resistance. Four of the strains, MTBR1/09, MTBR2/09, MTBR3/09 and MTB221/11 were subjected to drug susceptibility test (DST). All of the strains sequenced and submitted to the National Center for Biotechnology Information Sequence Read Archive were analyzed to identify the variants in the rpoB gene. The identified new variants were then subjected to docking to examine the drug-protein interactions. DST analysis revealed MTBR1/09, MTBR2/09 and MTBR3/09 were resistant to the RIF drug, while MTB221/11 was a presumptive susceptible strain. Two new variants were observed, the deletion (Phe433_Met434delinsLeu in MTBR1/09) and missense (Lys37Arg in MTBR3/09) variants. Meanwhile, the His445Leu, Ser450Leu, Asp103Asp, Ala1075Ala were reported variants. Docking of RIF to MTBR1/09 and MTBR3/09 mutant models revealed the RIF bound to the RIF binding site at different binding affinity and conformation. Concurrently, the new variants caused the RIF to bind to the different active site and neighboring residues. Findings from DST and docking analyses indicate that new variants potentially disturb the RIF inhibition in RpoB mutant proteins, and thus might be responsible to cause the RIF resistance.

scholarly journals Rifamycin action on RNA polymerase in antibiotic-tolerant Mycobacterium tuberculosis results in differentially detectable populations

2017 ◽  
Vol 114 (24) ◽  
pp. E4832-E4840 ◽  
Author(s):  
Kohta Saito ◽  
Thulasi Warrier ◽  
Selin Somersan-Karakaya ◽  
Lina Kaminski ◽  
Jianjie Mi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Rna Polymerase ◽  
Resistant Strain ◽  
Reliable Method ◽  
Drug Susceptibility ◽  
Β Subunit ◽  
Liquid Media ◽  
Colony Forming Units ◽  
Independent Confirmation

Mycobacterium tuberculosis (Mtb) encounters stresses during the pathogenesis and treatment of tuberculosis (TB) that can suppress replication of the bacteria and render them phenotypically tolerant to most available drugs. Where studied, the majority of Mtb in the sputum of most untreated subjects with active TB have been found to be nonreplicating by the criterion that they do not grow as colony-forming units (cfus) when plated on agar. However, these cells are viable because they grow when diluted in liquid media. A method for generating such “differentially detectable” (DD) Mtb in vitro would aid studies of the biology and drug susceptibility of this population, but lack of independent confirmation of reported methods has contributed to skepticism about their existence. Here, we identified confounding artifacts that, when avoided, allowed development of a reliable method of producing cultures of ≥90% DD Mtb in starved cells. We then characterized several drugs according to whether they contribute to the generation of DD Mtb or kill them. Of the agents tested, rifamycins led to DD Mtb generation, an effect lacking in a rifampin-resistant strain with a mutation in rpoB, which encodes the canonical rifampin target, the β subunit of RNA polymerase. In contrast, thioridazine did not generate DD Mtb from starved cells but killed those generated by rifampin.

Spoligotyping and Drug Sensitivity of Mycobacterium tuberculosis isolated from Pulmonary Tuberculosis Patients in the Arsi Zone of South Eastern Ethiopia

2019 ◽  
Author(s):  
Belete Haile Nega ◽  
Ketema Tafess ◽  
Aboma Zewude ◽  
Bazezew Yenew ◽  
Gilman SIU ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Sensitivity ◽  
Scientific Information ◽  
Rpob Gene ◽  
Drug Susceptibility ◽  
Strain Identification ◽  
First Line ◽  
Eastern Ethiopia ◽  
Arsi Zone ◽  
Mycobacterium Africanum

Abstract Background Tuberculosis (TB) is one of the leading disease causing morbidity and mortality in different zones of Ethiopia including the Arsi Zone. However, little or no scientific information is available on the strains of Mycobacterium tuberculosis and their drug sensitivity profiles in this Zone. This study was conducted to identify the strains of M. tuberculosis and evaluate their drug sensitivity profiles. Methodology A total of 111 clinical isolates of M. tuberculosis from patients with pulmonary TB in the Arsi Zone were used for this study. The region of difference 9 (RD 9)-based polymerase chain reaction (PCR)and spoligotyping methods were used for speciation and strain identification of Mycobacterium tuberculosis respectively.The spoligotyping patterns were compared with the international SpolDB4 (SITVIT) and Run TB-Lineage used for the identification of lineages. The phenotypic drug susceptibility patterns were confirmed by BD BactecMGIT 960 SIRE test and GenoType MTBDRplus line probe assays were used for the detection the drug resistance-conferring mutations of the isolates. Result The spoligotype patterns of 83% (92/111) of the isolates were interpretable and 56 different patterns were identified. Twenty-two of these patterns were shared types while the remaining 34 were orphans. The predominant shared types were spoligotype international type (SIT) 149 and SIT53, each consisting of 12 and 11 isolates, respectively. The lineages identified were Euro-American, East-African-Indian, Mycobacterium-africanum, and Indo-Oceanic in descending order. Phenotypically, 17.2% of the 64 tested isolates were resistant to any of the four first-line drugs while 3.1% of them were multi-drug resistant (MDR). Higher (6.2%) monoresistance was observed to Streptomycin followed by Isoniazid (3.1%) while no resistance was observed either to Rifampicin or to Ethambutol. Genotypically, five (5.4%) isolates were resistant to Isoniazid and mutated at codon S315T1 of katG. On the other hand, only 1.1% of the isolates was resistant to Rifampicin and mutated at codon S531L of rpoB gene. Conclusion The proportion of orphan strains isolated in this study was high, which could suggest the presence of new strains in the Zone. Moreover, the study showed relatively high percentage of mono-resistance to any four first-line drugs warranting for the need to strengthen the control efforts.

scholarly journals Genetic diversity and drug susceptibility patterns of the Mycobacterium tuberculosis complex in Yunnan, China

2019 ◽  
Vol 39 (5) ◽  
Author(s):  
Ruolan Bai ◽  
Shuijing Chi ◽  
Xiaofei Li ◽  
Xiting Dai ◽  
Zhenhua Ji ◽  
...  
Keyword(s):  
Public Health ◽  
Genetic Diversity ◽  
Mycobacterium Tuberculosis ◽  
Public Health Problem ◽  
Drug Susceptibility ◽  
Drug Resistant ◽  
Global Public Health ◽  
High Genetic Diversity ◽  
Dominant Feature ◽  
Mdr Tb

AbstractTuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis (Mtb) which has been threatening global public health for many years. High genetic diversity is dominant feature of Mtb. Increasing cases of multidrug-resistant (MDR) tuberculosis (MDR-TB) is a serious public health problem to TB control in China. Spontaneous mutations in the Mtb genome can alter proteins which are the target of drugs, making the bacteria drug resistant. The purpose of the present study was to analyze the genotype of Mtb isolates from some areas in Yunnan, China and explore the association between genotypes and MDR-TB. Using spoligotyping, we identified Beijing genotypes, six non-Beijing genotypes and a number of orphan genotypes from 270 Mtb isolates from patients in Yunnan Province during 2014–2016. Of 270 Mtb isolates, 102 clinical Mtb strains were identified as drug-resistant (DR) by drug susceptibility testing (DST), among them, 52 MDR strains. Beijing genotypes occupied the highest MDR proportion (78.85%) followed by the orphan genotypes (15.38%). The characteristics of MDR strains showed high genetic diversity. The results will help to efficiently improve diagnosis and treatment and provide valuable information for Mtb molecular epidemiology.

scholarly journals Association of ω with the C-Terminal Region of the β′ Subunit Is Essential for Assembly of RNA Polymerase in Mycobacterium tuberculosis

2018 ◽  
Vol 200 (12) ◽  
Author(s):  
Chunyou Mao ◽  
Yan Zhu ◽  
Pei Lu ◽  
Lipeng Feng ◽  
Shiyun Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Mycobacterium Tuberculosis ◽  
Rna Polymerase ◽  
Essential Role ◽  
Β Subunit ◽  
Content Type ◽  
E Coli ◽  
Core Enzyme ◽  
Loop Region

ABSTRACT The ω subunit is the smallest subunit of bacterial RNA polymerase (RNAP). Although homologs of ω are essential in both eukaryotes and archaea, this subunit has been known to be dispensable for RNAP in Escherichia coli and in other bacteria. In this study, we characterized an indispensable role of the ω subunit in Mycobacterium tuberculosis . Unlike the well-studied E. coli RNAP, the M. tuberculosis RNAP core enzyme cannot be functionally assembled in the absence of the ω subunit. Importantly, substitution of M. tuberculosis ω with ω subunits from E. coli or Thermus thermophilus cannot restore the assembly of M. tuberculosis RNAP. Furthermore, by replacing different regions in M. tuberculosis ω with the corresponding regions from E. coli ω, we found a nonconserved loop region in M. tuberculosis ω essential for its function in RNAP assembly. From RNAP structures, we noticed that the location of the C-terminal region of the β′ subunit (β′CTD) in M. tuberculosis RNAP but not in E. coli or T. thermophilus RNAP is close to the ω loop region. Deletion of this β′CTD in M. tuberculosis RNAP destabilized the binding of M. tuberculosis ω on RNAP and compromised M. tuberculosis core assembly, suggesting that these two regions may function together to play a role in ω-dependent RNAP assembly in M. tuberculosis . Sequence alignment of the ω loop and the β′CTD regions suggests that the essential role of ω is probably restricted to mycobacteria. Together, our study characterized an essential role of M. tuberculosis ω and highlighted the importance of the ω loop region in M. tuberculosis RNAP assembly. IMPORTANCE DNA-dependent RNA polymerase (RNAP), which consists of a multisubunit core enzyme (α 2 ββ′ω) and a dissociable σ subunit, is the only enzyme in charge of transcription in bacteria. As the smallest subunit, the roles of ω remain the least well studied. In Escherichia coli and some other bacteria, the ω subunit is known to be nonessential for RNAP. In this study, we revealed an essential role of the ω subunit for RNAP assembly in the human pathogen Mycobacterium tuberculosis , and a mycobacterium-specific ω loop that plays a role in this function was also characterized. Our study provides fresh insights for further characterizing the roles of bacterial ω subunit.

Mapping of sequences required for the translation of the β subunit of Escherichia coli RNA polymerase

1997 ◽  
Vol 43 (9) ◽  
pp. 819-826
Author(s):  
Luciano Passador ◽  
Thomas Linn
Keyword(s):  
Escherichia Coli ◽  
Rna Polymerase ◽  
Translational Regulation ◽  
Rpob Gene ◽  
Β Subunit ◽  
E Coli ◽  
Lacz Fusions ◽  
Translational Start ◽  
Genetic Constructs ◽  
Expression Plasmids

Previous experiments using expression plasmids which overproduce the β and β′ subunits of Escherichia coli RNA polymerase suggested that regions considerably upstream of the start of the rpoB gene, which encodes the β subunit, are required for its efficient synthesis. To further delineate the required regions, a collection of genetic constructs that contained varying amounts of the region either upstream or downstream of the translational start of rpoB was assembled. Measurements of β and β′ synthesis and rpoB mRNA production from a series of rpoBC expression plasmids indicated that sequences extending more than 43 bp but less than 79 bp upstream of rpoB are required for the efficient translation of rpoB mRNA. This result was confirmed by β-galactosidase measurements from a series of rpoB-lacZ fusions that have the same set of end points upstream of rpoB as the expression plasmids. A second set of gene fusions containing differing amounts of the sequence distal to the start of rpoB fused in frame to lacZ revealed that more than 29 bp but less than 70 bp of rpoB was required for efficient translation.Key words: RNA polymerase, E. coli, translational regulation.

scholarly journals rpoB gene mutations in rifampin-resistant Mycobacterium tuberculosis isolates from rural areas of Zhejiang, China

2021 ◽  
Vol 49 (3) ◽  
pp. 030006052199759
Author(s):  
Mei-Chun Zeng ◽  
Qing-Jun Jia ◽  
Lei-Ming Tang
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Rural Areas ◽  
Gene Mutations ◽  
Gene Sequencing ◽  
Rpob Gene ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Drug Susceptibility Testing ◽  
Drug Resistant ◽  
Extensively Drug Resistant

Objective The aim was to analyze genetic mutations in the rpoB gene of rifampin-resistant Mycobacterium tuberculosis isolates (RIFR-MTB) from Zhejiang, China. Methods We prospectively analyzed RIFR-associated mutations in 13 rural areas of Zhejiang. Isolates were subjected to species identification, phenotype drug susceptibility testing (DST), DNA extraction, and rpoB gene sequencing. Results A total of 103 RIFR isolates were identified by DST (22 RIFR only, 14 poly-drug resistant, 49 multidrug resistant, 13 pre-extensively drug resistant [pre-XDR], and 5 extensively drug resistant [XDR]) from 2152 culture-positive sputum specimens. Gene sequencing of rpoB showed that the most frequent mutation was S450L (37.86%, 39/103); mutations P280L, E521K, and D595Y were outside the rifampicin resistance-determining region (RRDR) but may be associated with RIFR. Mutations associated with poly-drug resistant, pre-XDR, and XDR TB were mainly located at codon 445 or 450 in the RRDR. Conclusions The frequency of rpoB RRDR mutation in Zhejiang is high. Further studies are needed to clarify the relationships between RIFR and the TTC insertion at codon 433 in the RRDR and the P280L and D595Y mutations outside the RRDR.

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