Growth-rate-dependent gene expression in Bacillus subtilis

The B. subtilis transcriptome was analyzed under conditions of different growth rates, i.e. during growth in different cultivation media. Gene-level intensities were scaled based on the intensity values of 10 spike-in transcripts. This approach allowed to determine the total mRNA fraction out of the total RNA pool. The data revealed that the proportion of total mRNA in total RNA remained constant across samples which implies that total mRNA abundance in B. subtilis increases proportionally to the growth rate. Total RNA was extracted from cells grown in 4 different cultivation media at growth rates from μ=0.4 h-1 to μ=1.70 h-1. Microarray hybridizations were performed with RNA from four biological replicates. Samples were labeled with Cy3 (one-color hybridizations).