Disease relevance of embB

• Mutations in embB lead to resistance to EMB in Mycobacterium tuberculosis [1].

High impact information on embB

• All three mutants were viable, and among the three, the slowest growing embB(-) mutant encountered profound morphological changes and exhibited a higher sensitivity to hydrophobic drugs and detergents, presumably due to an increase in cell wall permeability [2].
• Upon complementation with the embB and embA wild-type genes, the phenotype of the mutants reverted to wild-type, in that normal AG was resynthesized [2].
• In Mycobacterium smegmatis and Mycobacterium tuberculosis, they belong to an operon comprising three genes, embC, embA, and embB [2].
• Furthermore, chemical analyses showed that there was a diminution in the arabinose content of arabinogalactan from the embA(-) and embB(-) mutants [2].
• Significance of Mutations in embB Codon 306 for Prediction of Ethambutol Resistance in Clinical Mycobacterium tuberculosis Isolates [3].

Chemical compound and disease context of embB

• Novel mutations within the embB gene in ethambutol-susceptible clinical isolates of Mycobacterium tuberculosis [4].

Biological context of embB

• Role of embB codon 306 mutations in Mycobacterium tuberculosis revisited: a novel association with broad drug resistance and IS6110 clustering rather than ethambutol resistance [5].
• Substitutions in the embB gene were found by SSCP analysis in 15 (45%) and by sequencing in 17 (52%) of the 33 EMB-resistant isolates [6].

Anatomical context of embB

• Most isolates (68%) with resistance-associated mutations in a single gene had nucleotide changes in embB, a gene encoding an arabinosyltransferase involved in cell wall biosynthesis [7].
• Here, we describe a simple and culture-independent technique to detect embB codon 306 mutations directly from sputum samples, requiring little more than a PCR machine and a simple agarose minigel [8].

Associations of embB with chemical compounds

• Role of embB in natural and acquired resistance to ethambutol in mycobacteria [1].
• We also designed probes to examine codon 315 of katG and codon 306 of embB for mutations associated with resistance to isoniazid and ethambutol, respectively [9].
• The beta(1-->2) arabinosyl transferase activity was more in evidence in the presence of the O-alkyl disaccharide acceptor, whereas both transferases were about equivalent in the presence of the S-alkyl trisaccharide acceptor [10].

Other interactions of embB

• The most common nucleotide polymorphism in our isolates was at codons 306 and 299 in the embB gene and at codon 270 in the embC gene [11].
• Characterisation of rpsL, rrs and embB mutations associated with streptomycin and ethambutol resistance in Mycobacterium tuberculosis [6].

Analytical, diagnostic and therapeutic context of embB

• Primers to amplify the embB and embC gene were designed, and polymerase chain reaction products were subjected for sequence analysis [11].
• Recently, genetic events resulting in structural mutations at embB have been proposed as major contributors to the EMB-resistance of isolates whose minimum inhibitory concentration (MIC) level is higher than 20 microgram/ml [12].

References