Transcriptome analysis of Pseudomonas aeruginosa PAO1 WT, ΔpauA2 mutant, and ΔpauA2 suppressor

PauA2 plays an essential role in spermine catabolism and that exogenous spermine exerts a bactericidal effect on the ΔpauA2 mutant of P. aeruginosa. Not only subjected to growth inhibition by spermine, the pauA2 mutant without a functional γ-glutamylpolyamine synthetase PauA2 became more sensitive to β-lactam antibiotics in human serum. To explore PauA2 as a potential target of drug development, suppressors of the pauA2 mutant were isolated from selection plates containing spermine. These suppressors share common changes in various phenotypes. Genome resequencing of a representative suppressor revealed a unique mutation at the phoU gene, and a constitutive expression of the Pho regulon as evidenced by measurements of transcriptome analysis. We conducted two independent microarray experiments for each of strains. P. aeruginosa PAO1 and its derivatives was grown aerobically in LB broth along with 300 rpm shaking at 37°C.

PauA2在精胺分解代谢中发挥关键作用，且外源性精胺对铜绿假单胞菌（P. aeruginosa）的ΔpauA2突变株具有杀菌活性。该缺乏功能性γ-谷氨酰多胺合成酶（PauA2）的pauA2突变株，不仅会受到精胺的生长抑制，在人血清中还对β-内酰胺类抗生素更为敏感。为将PauA2开发为潜在药物靶点，研究人员从添加精胺的筛选平板中分离得到了pauA2突变株的抑制突变株。这些抑制突变株在多种表型上存在共同的特征性变化。对一株代表性抑制突变株进行基因组重测序后发现，其phoU基因存在一处独特突变，且转录组分析结果证实Pho调控子（Pho regulon）呈组成型表达。我们针对每一株菌株均开展了两次独立的微阵列（microarray）实验。铜绿假单胞菌PAO1及其衍生菌株均在37℃、300 rpm振荡条件下，于LB肉汤（LB broth）中进行有氧培养。