College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China.
OIE Reference Laboratory for Swine Streptococcosis, Nanjing, China.
Arch Microbiol. 2022 Apr 6;204(5):244. doi: 10.1007/s00203-022-02854-5.
Streptococcus suis is an important emerging zoonosis that causes economic losses in the pig industry and severe threats to public health. Transcriptional regulators play essential roles in bacterial adaptation to host environments. In this study, we identified a novel XRE family transcriptional regulator in S. suis CZ130302, XtrSs, involved in the bacterial fitness to hydrogen peroxide stress. Based on electrophoretic mobility shift and β-galactosidase activity assays, we found that XtrSs auto-regulated its own transcription and repressed the expression of its downstream gene psePs, a surface protein with unknown function in S. suis, by binding to a palindromic sequence from the promoter region. Furthermore, we proved that the deletion of the psePs gene attenuated bacterial antioxidant response. Phylogenetic analysis revealed that XtrSs and PsePs naturally co-existed as a combination in most S. suis genomes. Collectively, we demonstrated the binding characteristics of XtrSs in S. suis and provided a new insight that XtrSs played a critical role in modulating psePs to the hydrogen peroxide resistance of S. suis.
猪链球菌是一种重要的新兴人畜共患病病原体，它给养猪业造成了经济损失，并严重威胁着公共卫生。转录调控因子在细菌适应宿主环境方面发挥着重要作用。在本研究中，我们在猪链球菌 CZ130302 中鉴定到了一个新型的 XRE 家族转录调控因子 XtrSs，该因子参与了细菌对过氧化氢应激的适应。通过电泳迁移率变动分析和β-半乳糖苷酶活性测定，我们发现 XtrSs 通过结合其启动子区域的一个回文序列，自我调控转录并抑制其下游基因 psePs 的表达，psePs 是猪链球菌中一种具有未知功能的表面蛋白。此外，我们证明了 psePs 基因的缺失削弱了细菌的抗氧化反应。系统发育分析表明，XtrSs 和 PsePs 作为一个组合在大多数猪链球菌基因组中自然共存。综上所述，我们揭示了 XtrSs 在猪链球菌中的结合特征，并提供了新的见解，即 XtrSs 在调节 psePs 以增强猪链球菌对过氧化氢的抗性方面发挥着关键作用。
