Disease relevance of strA

• All ampicillin- and streptomycin-resistant E. coli O26 carried ampC and strA-strB gene sequences, respectively [1].
• Deletions in either of the genes in the strA-strB gene pair of Erwinia amylovora plasmid pEa34 resulted in a dramatic decrease in streptomycin resistance (SmR), but SmR was restored to high levels by complementation [2].
• The instability of the strA gene was particularly enhanced when the Val51 residue in the middle of S12 protein was replaced by Leu, suggesting enhanced toxicity of the altered S12 [3].
• An str gene cluster containing at least four genes (strR, strA, strB, and strC) involved in streptomycin biosynthesis or streptomycin resistance or both was self-cloned in Streptomyces griseus by using plasmid pOA154 [4].
• A PCR was developed and used for detection of the strA-strB gene pair encoding streptomycin resistance in gram-negative bacteria [5].

High impact information on strA

• Other genes conferring resistance to aminoglycosides (aacC2, strA, and strB), chloramphenicol (catA2), sulfonamides (sul2), tetracycline (tetD), and trimethoprim (dfrA14) were also detected in pK245 [6].
• Strains harbouring both the strA-strB genes and an aadA gene cassette had higher streptomycin MICs than those harbouring either alone [7].
• Expression and identification of the strA-strB gene pair from streptomycin-resistant Erwinia amylovora [2].
• Since the strAS gene was stably maintained throughout approx. 100 cell doublings when its expression was abolished, most probably it is the gene product rather than the nucleotide sequence itself that is responsible for the instability of strA gene on HCN plasmids [3].
• Localized mutagenesis and selection for streptomycin resistance were utilized to isolate a chloramphenicol resistance mutation in Escherichia coli K-12 linked to the strA (rpsL) locus [8].

Chemical compound and disease context of strA

• Increased loss of duplicated genes in streptomycin-resistant (strA) mutants of Escherichia coli k-12 [9].
• Mutations conferring resistance to low levels of kanamycin in Escherichia coli have been mapped at 3 locations: the unc locus (min. 83), a locus we have designated kanA (MIN. 72), close to strA (rpsL), and a locus at min [10].

Biological context of strA

• Other plasmids carrying floR and aadB also carried tet(A), sul2, strA/strB, bla(CMY-2) and occasionally aac(3)IV [11].
• The recombination-dependent loss of a duplicated portion of the Escherichia coli chromosome is five- to tenfold greater in strains containing streptomycin resistance (strA) mutations than in the strA+ parental strain [9].
• (iv) The rate of polypeptide bond formation which was determined from the kinetics of beta-galactosidase induction is not significantly changed in strains bearing the ram and the strA (streptomycin-resistant) alleles [12].

Associations of strA with chemical compounds

• Moreover, a truncated copy of Tn5393 with complete streptomycin resistance genes strA and strB was found upstream of the floR gene of pMBSF1 [13].

References