Analyses of mutations in rpoB subunit of Escherichia coli that lead to resistance to rifampicin have been invaluable in providing insight into events during transcription continue to be discovered. Earlier we reported that rpoB12 suppresses over-expression of cps genes in Δlon mutant of E.coli, by interfering with the transcription of rcsA. Here we report Microarray based Transcriptome profile of Δlon and Δlon rpoB12 strains. The data analyses clearly reveal that rpoB12 mutation results in the differential expression of ∼450 genes. The transcription profiles of some of the genes namely, rcsA, gadE, csgD, bolA, ypdI, dnaJ, clpP, csrA and hdeA are significantly altered, particularly the genes implicated in virulence. Some of the phenotypic traits namely, biofilm formation, motility, curli synthesis and ability to withstand acidic stress in a lon⁺rpoB12 strain were assessed. The results clearly indicate that rpoB12 up-regulates biofilm formation and curli synthesis while it makes the cells sensitive for growth in acidic medium and inhibits motility almost completely. Furthermore, rpoB12 modulates the expression profile of a significant number of genes involved in stress responses, genes encoding small RNAs. Thus, this study reveals the versatile role of the rpoB12 mutation, especially its impact on the regulation of genes related to virulence and highlights its medical importance.

大肠杆菌的rpoB亚基突变导致对利福平的耐药性的分析，对于提供对转录过程中事件的洞察力的发现是非常有价值的。先前我们曾报道rpoB12通过干扰rcsA的转录来抑制大肠杆菌Δlon突变体中cps基因的过度表达。在这里，我们报告基于微阵列的Δlon和ΔlonrpoB12菌株的转录组图谱。数据分析清楚地表明，rpoB12突变导致约450个基因的差异表达。某些基因（即rcsA，gadE，csgD，bolA，ypdI，dnaJ，clpP，csrA和hdeA）的转录谱发生了显着改变，特别是涉及毒力的基因。表型的一些特征，即生物膜的形成，运动性，卷曲的合成以及长期抵抗酸性胁迫的能力⁺ rpoB12菌株进行了评估。结果清楚地表明，rpoB12上调生物膜的形成和卷曲的合成，同时使细胞对酸性培养基中的生长敏感并几乎完全抑制运动。此外，rpoB12调节涉及应激反应的大量基因（编码小RNA的基因）的表达谱。因此，这项研究揭示了rpoB12突变的多方面作用，特别是其对与毒力相关的基因调控的影响，并突出了其医学重要性。