BioProject

To investigate which cellular functions may be perturbed along the branches of a synthetic evolutionary tree obtained by incremental deletions of large genomic regions, we subjected six Bacillus subtilis strains to transcriptome profiling. More...

To investigate which cellular functions may be perturbed along the branches of a synthetic evolutionary tree obtained by incremental deletions of large genomic regions, we subjected six Bacillus subtilis strains to transcriptome profiling. These six strains are : MS (~3.98 Mbp), which is already a genome-reduced derivative of the B. subtilis 168 (~4.22 Mbp) and the root of our evolutionary tree; MGP254 (~2.73 Mbp), the farthest genome-reduced strain; MGP234 (~2.81 Mbp), another terminal leaf in our tree; MGP181 (~2.87 Mb) and MGP192 (~2.85 Mbp), two intermediate strains in the ancestor lineage common to MGP254 and MGP234; and finally MGP229 (2.82 Mbp), an intermedidate strain between MGP192 and MGP254 (i.e. an ancestor of MGP254 but not MGP234). The vast majority of genes conserved in the six strains displayed no differential expression, showing the robustness of the cell transcriptional network against massive genome reduction. Among deregulated genes, more than half could be explained by loss of known functions and aberrant transcription at deletion boundaries. An unexpected common feature in genome-reduced strains was the upregulation of genes involved in cell responses to oxidative stresses. Overall design: The transcriptome of each strain was assessed by separate hybridization of two RNA samples extracted from two independent cultures (biological duplicates). Less...