The function of the Staphylococcus aureus eukaryotic-like serine/threonine protein kinase PknB was investigated by transcriptome analysis using DNA-microarray technology and biochemical assays. The transcriptional profile reveals a strong regulatory impact of PknB on the expression of genes encoding proteins which are involved in purine and pyrimidine biosynthesis, cell wall metabolism, autolysis, and glutamine synthesis. Overall design: To investigate the functional role of PknB in S. aureus DNA microarray experiments were performed. In this experiment, the impact of the deletion of PknB was investigated. Each experiment was performed 5 times including a dye swap resulting in five chips per competitive comparison to increase reproducibility. All hybridizations were done with equal amounts of cDNA probes.