Whole-transcriptome analysis of Staphylococcus aureus under laboratory and infection-mimicking conditions

We report the condition-dependent transcriptome of S. aureus HG001, a derivative of strain NCTC 8325, by strand-specific tiling array hybridizations. More than 40 experimental conditions were investigated ranging from optimal in vitro growth to interaction with host cells. Analyses included the systematic mapping of transcription units, annotation of non-coding RNAs, the classification of promoters according to their dependency on SigA and SigB, and the prediction of potentially new transcription factor target sites. Antisense RNAs being of particular interest because of the small number of alternative sigma factors used by S. aureus were found to be relatively rare, overlapping only 6% of the annotated coding genes. RNA samples prepared from S. aureus HG001 grown in shake flask or cell culture infection experiments were reverse transcribed, labeled and hybridized to tiling arrays. Hybridizations were performed in triplicate using RNA isolated from independent cultures.