Disease relevance of bacA

• These mutants fell into four classes, as determined by replicon mobilization experiments and genetic linkage in phage transduction; one class corresponded to the bhb locus on pRmeSU47b, two classes mapped to different regions on the chromosome and the fourth, bdhA, represented by a single mutant, mapped to another pRmeSU47b locus, near bacA [1].
• The Rhizobium meliloti bacA gene encodes a function that is essential for bacterial differentiation into bacteroids within plant cells in the symbiosis between R. meliloti and alfalfa [2].
• Genetic analysis of the Rhizobium meliloti bacA gene: functional interchangeability with the Escherichia coli sbmA gene and phenotypes of mutants [2].
• Sinorhizobium meliloti bacA mutants are symbiotically defective, deoxycholate sensitive, and bleomycin resistant [3].

High impact information on bacA

• Here a highly conserved B. abortus homolog of the R. meliloti bacA gene, which encodes a putative cytoplasmic membrane transport protein required for symbiosis, was identified [4].
• An isogenic B. abortus bacA mutant exhibited decreased survival in macrophages and greatly accelerated clearance from experimentally infected mice compared to the virulent parental strain [4].
• To discover bacterial genes involved in the infection and differentiation stages of symbiosis, we obtained genes expressed at the appropriate time and place in the nodule by identifying promoters that are able to direct expression of the bacA gene, which is required for bacteroid differentiation [5].
• The bacA bacterial mutant, which senesces upon deposition into plant cells, and two plant mutants with defects in nitrogen fixation (dnf1 and dnf5) induce MtLEC4 and ENOD2 but not MtN31, MtCAM1, or MtLB1 [6].
• We show that the bleomycin resistance phenotype is independent of the lipid A alteration and that the changes giving rise to both phenotypes are likely to be involved in the inability of bacA mutants to persist within their hosts [3].

Biological context of bacA

• However, the additional phenotypes of bacA mutants identified in this study suggest the alternative possibility that BacA may be needed for membrane integrity, which is likely to be critically important during the early stages of bacterial differentiation within plant cells [2].

Associations of bacA with chemical compounds

• The R. meliloti bacA386::Tn(pho)A mutant, as well as a newly constructed bacA deletion mutant, was found to show increased resistance to bleomycin [2].
• However, it also showed increased resistance to certain aminoglycosides and increased sensitivity to ethanol and detergents, suggesting that the loss of bacA function causes some defect in membrane integrity [2].
• However, analysis of crude preparations of the bacA mutant LPS suggested that, unlike that for LpsB, BacA function did not affect the carbohydrate composition of the LPS [7].
• We have created a set of 20 site-directed mutants in which selected individual amino acids in bacA were replaced with glycine residues [8].

Other interactions of bacA

• In addition, an S. meliloti lpsB mutant that is defective at a stage in infection of the host similar to that found for a bacA mutant is also sensitive to the same agents, and the carbohydrate content of its lipopolysaccharide (LPS) is altered [7].

References