Disease relevance of rrs

• An A1400G mutation of the rrs gene was identified in Mycobacterium tuberculosis (MTB) strain ATCC 35827 and in 13 MTB clinical isolates resistant to amikacin-kanamycin (MICs, >128 microg/ml) [1].

High impact information on rrs

• Streptomycin resistance in about one-half of M. tuberculosis isolates is associated with missense mutations in the rpsL gene coding for ribosomal protein S12 or nucleotide substitutions in the 16S rRNA gene (rrs) [2].
• The rrs genes of all mutants were sequenced, and the tlyA genes were sequenced for mutants selected on capreomycin, viomycin, or both; MICs of all four drugs were determined [3].
• Mutations in the 16S rRNA gene (rrs) have been associated with resistance to each of the drugs; however, reports of cross-resistance to the drugs have been variable [3].
• We investigated the role of rrs mutations in capreomycin resistance and examined the molecular basis of cross-resistance to the four drugs in M. tuberculosis laboratory-generated mutants and clinical isolates [3].
• Molecular characterization of a streptomycin-dependent mutant of Mycobacterium tuberculosis revealed the presence of a novel mutation in the rrs gene encoding 16S rRNA [4].

Chemical compound and disease context of rrs

• In Mycobacterium smegmatis and a limited number of Mycobacterium tuberculosis strains, the involvement of alterations of the 16S rRNA gene (rrs) in resistance to kanamycin has been shown [5].

Biological context of rrs

• Although such resistance is often mediated by mutations within rrs, a 16S rRNA gene or rpsL, which encodes the ribosomal protein S12, these mutations are found in a limited proportion of clinically isolated streptomycin-resistant M. tuberculosis strains [6].
• Of the 98 SM-resistant isolates, 78 (79.6%) had missense mutations in codon 43 or 88 of rpsL resulting in a Lys to Arg substitution, 6 (6.1%) had mutations of the rrs gene at positions 513 A to C or T or 516 C to T, and 14 (14.3%) had the wild-type sequence [7].
• To investigate the extent to which mutations in a specific region of the rrs gene and the kanamycin-resistant phenotype in clinically isolated M. tuberculosis strains were correlated, 43 kanamycin-resistant strains (MICs, > or =200 microg/ml), 71 kanamycin-susceptible strains, and 4 type strains were examined [5].
• The 300-bp DNA fragments carrying the rrs gene and the intervening sequence between the rrs gene and 23S rRNA (rrl) gene fragments were amplified by PCR and were subjected to PCR-based direct sequencing [5].

Associations of rrs with chemical compounds

• All of the M. smegmatis strains with high-level kanamycin resistance had a nucleotide substitution from A to G at position 1389 of the 16S rRNA gene (rrs) [8].

References