Critchlow Jeanette M, Barraza Juan P, Munneke Matthew J, Krystofiak Evan, Green Erin R, Skaar Eric P
Microbe-Host Interactions Training Program, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
Department of Pathology Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Infect Immun. 2025 Feb 18;93(2):e0042224. doi: 10.1128/iai.00422-24. Epub 2025 Jan 23.
is an opportunistic human pathogen that acquires nutrient metals from the vertebrate host amid infection. During zinc (Zn) scarcity, upregulates the expression of the predicted Zn metallochaperone, . Loss of compromises fitness during Zn deficiency, highlighting its role in this condition. To assess the contribution of ZigA to Zn-deficient , a multiparallel transposon sequencing and genetic interaction mapping approach was used. Transposon insertions in , encoding a predicted soluble lytic transglycosylase that tailors the bacterial cell wall, were enriched in the Zn-starved Δ transposon library. Based on previous studies as well as structural and sequence homology, we designated A1S_3027 as oluble ytic ransglycosylase (SltB). Further analyses revealed that inactivating rescued Δ fitness defects during Zn starvation. An ΔΔ mutant demonstrated altered cell envelope structures and increased cellular permeability, highlighting the roles of ZigA and SltB in maintaining cell envelope integrity. Furthermore, these mutants exhibited heightened resistance to β-lactam antibiotics and other cell wall-targeting agents. Alterations in cell envelope integrity in the ΔΔ mutant improved fitness in a murine pneumonia infection model, emphasizing the contribution of ZigA and SltB to pathogenesis. This study elucidates how functional interactions between ZigA and SltB modulate cell envelope integrity and pathogenesis of during Zn depletion. These findings reveal an interplay between metal homeostasis and cell envelope integrity, offering insights into how ZigA contributes to these critical cellular processes.
是一种机会性人类病原体，在感染过程中从脊椎动物宿主获取营养金属。在锌（Zn）缺乏时，上调预测的锌金属伴侣蛋白的表达。ZigA的缺失会损害锌缺乏时的适应性，突出了其在这种情况下的作用。为了评估ZigA对锌缺乏型的贡献，使用了多平行转座子测序和遗传相互作用图谱方法。在编码预测的可溶性溶菌转糖基酶（该酶可修饰细菌细胞壁）的中，转座子插入在锌饥饿的Δ转座子文库中富集。基于先前的研究以及结构和序列同源性，我们将A1S_3027指定为可溶性溶菌转糖基酶（SltB）。进一步分析表明，使失活可挽救锌饥饿期间Δ的适应性缺陷。一个ΔΔ突变体表现出改变的细胞包膜结构和增加的细胞通透性，突出了ZigA和SltB在维持细胞包膜完整性中的作用。此外，这些突变体对β-内酰胺抗生素和其他靶向细胞壁的药物表现出更高的抗性。ΔΔ突变体中细胞包膜完整性的改变提高了在小鼠肺炎感染模型中的适应性，强调了ZigA和SltB对发病机制的贡献。这项研究阐明了ZigA和SltB之间的功能相互作用如何在锌消耗期间调节细胞包膜完整性和的发病机制。这些发现揭示了金属稳态与细胞包膜完整性之间的相互作用，为ZigA如何促进这些关键细胞过程提供了见解。
