GSE121479
The conserved WhiA protein influences the fatty acid composition of the Bacillus subtilis cell membrane
The conserved WhiA protein family is present in most Gram-positive bacteria and plays a role in cell division. WhiA contains a DNA-binding motive and has been identified as a transcription factor in the actinomycetes. In Bacillus subtilis, a deletion of whiA influences cell division and chromosome segregation. However, WhiA does not seem to function as a transcription factor in this organism, and it is still unclear how WhiA influences these processes. The B. subtilis whiA gene is part of an operon and flanked by two metabolic genes, including yvcK required for growth under gluconeogenic conditions, and the gene encoding the catabolite repressor Crh. Therefore, B. subtilis WhiA might play a role in carbon metabolism which could indirectly affect cell division and chromosome maintenance. To study this, we followed a metabolomics approach and measured exo-metabolome flux during growth on different carbon sources, using nuclear magnetic resonance spectroscopy. The carbon utilization of wild type and whiA mutant cells was similar, however, the whiA mutant exhibited depleted pools of branched-chain fatty acid precursors and higher levels of acetate and 2-oxoglutarate. Transcriptome data could not link these effects to gene regulatory differences, but the reduction in branched-chain fatty acid precursors influenced the fatty acid composition of the cell membrane. In conclusion, WhiA does not participate in carbon catabolite regulation, but affects fatty acid composition of the membrane by an as yet unknown mechanism. We speculate that the effect on the membrane might be related to the pleiotropic phenotype of the B. subtilis whiA mutant. Overall design: wild type and whiA mutant