Department of Microbiology and Immunology, Emory University School of Medicinegrid.471395.d, Atlanta, Georgia, USA.
STD Laboratory Reference and Research Branch, Division of STD Prevention, NCHHSTP, Centers for Disease Control and Preventiongrid.416738.f, Atlanta, Georgia, USA.
mBio. 2022 Apr 26;13(2):e0027622. doi: 10.1128/mbio.00276-22. Epub 2022 Mar 8.
GdhR is a transcriptional repressor of the virulence factor gene , which encodes a unique l-lactate permease that has been linked to pathogenesis of Neisseria gonorrhoeae, and loss of can confer increased fitness of gonococci in a female mouse model of lower genital tract infection. In this work, we identified a single nucleotide polymorphism (SNP) in , which is often present in both recent and historical gonococcal clinical strains and results in a proline (P)-to-serine (S) change at amino acid position 6 (P6S) of GdhR. This mutation () was found to reduce GdhR transcriptional repression at in gonococcal strains containing the mutant protein compared to wild-type GdhR. By using purified recombinant proteins and DNA-binding and cross-linking experiments, we found that impairs the DNA-binding activity of GdhR at without an apparent effect on protein oligomerization. By analyzing a panel of U.S. (from 2017 to 2018) and Danish (1928 to 2013) clinical isolates, we observed a statistical association between and the previously described adenine deletion in the promoter of (-P A-del), encoding the repressor (MtrR) of the operon that encodes the MtrCDE multidrug efflux pump that can export antibiotics, host antimicrobials, and biocides. The frequent association of with the promoter mutation in these clinical isolates suggests that it has persisted in this genetic background to enhance expression, thereby promoting virulence. We report the frequent appearance of a novel SNP in the gene () possessed by Neisseria gonorrhoeae. The resulting amino acid change in the GdhR protein resulted in enhanced expression of a virulence gene () that has been suggested to promote gonococcal survival during infection. The mutant GdhR protein expressed by had a reduced ability to bind to its target DNA sequence upstream of Interestingly, was found in clinical gonococcal strains isolated in the United States and Denmark at a high frequency and was frequently associated with a mutation in the promoter of the gene encoding a repressor (MtrR) of both the antimicrobial efflux pump operon and . Given this frequent association and the known impact of these regulatory mutations, we propose that virulence and antibiotic resistance properties are often phenotypically linked in contemporary gonococcal strains.
GdhR 是毒力因子基因的转录抑制剂，该基因编码一种独特的 l-乳酸通透酶，与淋病奈瑟菌的发病机制有关，而缺失 gdhR 可使淋病奈瑟菌在雌性生殖道感染小鼠模型中的适应性增加。在这项工作中，我们在 gdhR 中发现了一个单核苷酸多态性（SNP），该 SNP 通常存在于近期和历史淋病奈瑟菌临床株中，导致 GdhR 第 6 位氨基酸（P6S）脯氨酸（P）到丝氨酸（S）的改变。与野生型 GdhR 相比，该突变（）导致含有突变蛋白的淋病奈瑟菌菌株中 gdhR 在 处的转录抑制减少。通过使用纯化的重组蛋白和 DNA 结合和交联实验，我们发现 不明显影响蛋白寡聚化，但会损害 GdhR 在 处的 DNA 结合活性。通过分析一组美国（2017 年至 2018 年）和丹麦（1928 年至 2013 年）的临床分离株，我们观察到 与先前描述的 启动子中的腺嘌呤缺失（-P A-del）之间存在统计学关联，该缺失编码 repressor（MtrR）的操纵子，该操纵子编码 MtrCDE 多药外排泵，可将抗生素、宿主抗菌剂和杀生剂排出。在这些临床分离株中， 与 启动子突变的频繁关联表明，它在这种遗传背景中持续存在以增强 的表达，从而促进毒力。我们报告了淋病奈瑟菌中一种新的 SNP（）在 基因中频繁出现。GdhR 蛋白的这种氨基酸变化导致一种毒力基因（）的表达增强，该基因被认为可促进淋病奈瑟菌在感染过程中的存活。由 表达的突变 GdhR 蛋白与 的上游靶 DNA 序列的结合能力降低。有趣的是，在美国和丹麦分离的临床淋病奈瑟菌菌株中发现了 ，且频率较高，且经常与编码抗生素外排泵操纵子和 的 repressor（MtrR）的基因启动子中的突变相关。鉴于这种频繁的关联以及这些调节突变的已知影响，我们提出，在当代淋病奈瑟菌菌株中，毒力和抗生素耐药性通常是表型相关的。
