University of Hawai'i, John A. Burns School of Medicine, Department of Tropical Medicine, Medical Microbiology and Pharmacology, Honolulu, HI, USA.
University of Hawai'i, John A. Burns School of Medicine, Department of Pediatrics, Honolulu, HI, USA.
Microbiology (Reading). 2010 Oct;156(Pt 10):3085-3095. doi: 10.1099/mic.0.042614-0. Epub 2010 Jul 15.
Expression of the extensive arsenal of virulence factors by Streptococcus pyogenes is controlled by many regulators, of which CovRS is one of the best characterized and can influence ∼15 % of the genome. Animal models have established that mutants of covRS arise spontaneously in vivo resulting in highly invasive organisms. We analysed a pharyngeal and a blood isolate of S. pyogenes recovered from the same individual 13 days apart. The two isolates varied in many phenotypic properties including SpeB production, which were reflected in transcriptomic analyses. PFGE, multilocus sequence typing and partial sequencing of some key genes failed to show any differences except for an 11 bp insert in the covS gene in the blood isolate which caused a premature termination of transcription. Complementation of a fully functional covS gene into the blood isolate resulted in high expression of CovS and expression of speB. These results, showing a pharyngeal and a blood isolate from a single individual differing by a simple insertion, provide evidence for the model that regulatory gene mutations allow S. pyogenes to invade different niches in the body.
化脓链球菌表达广泛的毒力因子 arsenal 由许多调节剂控制，其中 CovRS 是最具特征性的调节剂之一，可影响大约 15%的基因组。动物模型已经证实，covRS 的突变体在体内自发产生，导致高度侵袭性的生物体。我们分析了从同一个体中相隔 13-14 天获得的咽和血源分离的化脓链球菌。这两种分离株在许多表型特性上存在差异，包括 SpeB 产生，这反映在转录组分析中。PFGE、多位点序列分型和一些关键基因的部分测序除了在血源分离株 covS 基因中发现的 11 个碱基插入导致转录提前终止外，没有显示出任何差异。将功能齐全的 covS 基因互补到血源分离株中，导致 CovS 和 speB 的高表达。这些结果显示，来自单个个体的咽和血源分离株存在一个简单的插入差异，为调节基因突变使化脓链球菌能够侵入体内不同小生境的模型提供了证据。
