Infectious Bacterial Disease Research Unit, USDA Agricultural Research Service, National Animal Disease Center, Ames, Iowa, USA.
National Veterinary Services Laboratories, USDA Animal and Plant Health Inspection Service, National Center for Animal Health, Ames, Iowa, USA.
mBio. 2024 Sep 11;15(9):e0151624. doi: 10.1128/mbio.01516-24. Epub 2024 Aug 13.
Leptospirosis, caused by pathogenic bacteria from the genus , is a global zoonosis responsible for more than one million human cases and 60,000 deaths annually. The disease also affects many domestic animal species. Historically, genetic manipulation of has been difficult to perform, resulting in limited knowledge on pathogenic mechanisms of disease and the identification of virulence factors. The application of CRISPR/Cas9 and its variations have helped fill these gaps but the generation of knockout mutants remains challenging because double-strand breaks (DSBs) inflicted by Cas9 nuclease are lethal to cells. The novel CRISPR prime editing (PE) strategy is the first precise genome-editing technology that allows deletions, insertions, and base substitutions without introducing DSBs. This revolutionary technique utilizes a nickase Cas9 that cleaves a single strand of DNA, coupled with an engineered reverse transcriptase and a modified single-guide RNA (termed prime editing guide RNA) containing an extended 3' end with the desired edits. We demonstrate the application of CRISPR-PE in both saprophytic and pathogenic from multiple species and serovars by introducing deletions or insertions into target DNA with a remarkable precision of just one nucleotide. Additionally, we demonstrate the ability to genetically manipulate , a prevalent pathogenic species of humans, domestic cattle, and wildlife animals. Rapid plasmid loss by mutated strains in liquid culture allows for the generation of knockout strains without selective markers, which can be readily used to elucidate virulence factors and develop optimized bacterin and/or live vaccines against leptospirosis.IMPORTANCELeptospirosis is a geographically widespread bacterial zoonosis. Genetic manipulation of pathogenic spp. has been laborious and difficult to perform, limiting our ability to understand how leptospires cause disease. The application of the CRISPR/Cas9 system to enhanced our ability to generate knockdown and knockout mutants; however, the latter remains challenging. Here, we demonstrate the application of the CRISPR prime editing technique in , allowing the generation of knockout mutants in several pathogenic species, with mutations comprising just a single nucleotide resolution. Notably, we generated a mutant in the background, a prevalent pathogenic species of humans and cattle. Our application of this method opens new avenues for studying pathogenic mechanisms of and the identification of virulence factors across multiple species. These methods can also be used to facilitate the generation of marker-less knockout strains for updated and improved bacterin and/or live vaccines.
钩端螺旋体病由螺旋体属的致病性细菌引起,是一种全球性的人畜共患病,每年导致超过 100 万例人类病例和 6 万人死亡。该疾病还影响许多家畜物种。从历史上看,对螺旋体属的遗传操作一直难以进行,导致对疾病的发病机制和毒力因子的了解有限。CRISPR/Cas9 及其变体的应用帮助填补了这些空白,但生成敲除突变体仍然具有挑战性,因为 Cas9 核酸酶造成的双链断裂(DSB)对螺旋体属细胞是致命的。新型的 CRISPR prime editing(PE)策略是第一个允许在不引入 DSB 的情况下进行缺失、插入和碱基替换的精确基因组编辑技术。这项革命性技术利用切口酶 Cas9 切割单链 DNA,同时结合工程化的逆转录酶和一种经过修饰的单链向导 RNA(称为 prime editing 向导 RNA),其 3' 端带有所需的编辑。我们通过在靶 DNA 中引入缺失或插入,证明了 CRISPR-PE 在来自多个物种和血清型的腐生和致病性螺旋体属中的应用,其精度高达一个核苷酸。此外,我们还证明了在普遍存在于人类、家畜和野生动物的致病性种属中进行遗传操作的能力。突变株在液体培养中的快速质粒丢失允许在没有选择性标记的情况下生成敲除株,这可以很容易地用于阐明毒力因子并开发针对钩端螺旋体病的优化菌苗和/或活疫苗。
重要性
钩端螺旋体病是一种具有广泛地理分布的细菌性人畜共患病。对致病性螺旋体属的遗传操作一直很费力且难以进行,限制了我们了解钩端螺旋体属如何引起疾病的能力。CRISPR/Cas9 系统在螺旋体属中的应用增强了我们生成敲低和敲除突变体的能力;然而,后者仍然具有挑战性。在这里,我们证明了 CRISPR prime editing 技术在螺旋体属中的应用,允许在几个致病性物种中生成敲除突变体,其突变仅包含一个核苷酸分辨率。值得注意的是,我们在 背景下生成了一个突变体, 是人类和牛的一种主要致病性种属。我们对该方法的应用为研究致病性机制和鉴定多种物种中的毒力因子开辟了新途径。这些方法还可用于促进无标记敲除株的生成,以更新和改进菌苗和/或活疫苗。