A homolog of Bacillus subtilis trigger factor in Listeria monocytogenes is involved in stress tolerance and bacterial virulence
A homolog of Bacillus subtilis trigger factor in Listeria monocytogenes is involved in stress tolerance and bacterial virulence
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DOI：
10.1128/aem.00624-06
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发表时间：
2006-10-01
影响因子：
4.4
通讯作者：
Charbit, Alain
中科院分区：
文献类型：
--
作者：
Bigot, Armelle;Botton, Eleonore;Charbit, Alain
分子伴侣在新生链多肽的折叠以及错误折叠或聚集蛋白质的重折叠和降解中发挥着至关重要的作用。它们还协助蛋白质移位并参与应激功能。我们确定了一个基因，命名为tig，编码一种蛋白质同源的触发因子（TF），细胞溶质核糖体相关的伴侣，单核细胞增生李斯特菌的基因组中。我们构建了一个染色体Delta tig缺失，并评估了突变对各种应激条件下肉汤中细菌生长和发病机制的影响。Δ tig缺失不影响细胞活力，但在热和乙醇应激的存在下损害存活。我们还确定了ffh基因，编码一种蛋白质同源的信号识别颗粒的SRP54真核成分。然而，Δ ffh缺失是不能容忍的，这表明Ffh是必需的，因为它是在枯草芽孢杆菌和大肠杆菌。因此，虽然TF对生长不利，但TF参与了L.单核细胞增多症Delta tig突变体在真核细胞中没有或表现出非常适度的细胞内存活缺陷。然而，在体内，它表现出降低的能力，坚持在脾脏和肝脏的感染小鼠，揭示了TF有一个作用，在致病性的L。单核细胞增多症
Molecular chaperones play an essential role in the folding of nascent chain polypeptides, as well as in the refolding and degradation of misfolded or aggregated proteins. They also assist in protein translocation and participate in stress functions. We identified a gene, designated tig, encoding a protein homologous to trigger factor (TF), a cytosolic ribosome-associated chaperone, in the genome of Listeria monocytogenes. We constructed a chromosomal Delta tig deletion and evaluated the impact of the mutation on bacterial growth in broth under various stress conditions and on pathogenesis. The Delta tig deletion did not affect cell viability but impaired survival in the presence of heat and ethanol stresses. We also identified the ffh gene, encoding a protein homologous to the SRP54 eukaryotic component of the signal recognition particle. However, a Delta ffh deletion was not tolerated, suggesting that Ffh is essential, as it is in Bacillus subtilis and Escherichia coli. Thus, although dispensable for growth, TF is involved in the stress response of L. monocytogenes. The Delta tig mutant showed no or very modest intracellular survival defects in eukaryotic cells. However, in vivo it showed a reduced capacity to persist in the spleens and livers of infected mice, revealing that TF has a role in the pathogenicity of L. monocytogenes.