CodY-mediated regulation of Streptococcus pyogenes exoproteins.
CodY-mediated regulation of Streptococcus pyogenes exoproteins.
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DOI：
10.1186/1471-2180-12-114
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发表时间：
2012-06-21
期刊：
影响因子：
4.2
通讯作者：
Chaussee MS
中科院分区：
文献类型：
--
作者：
McDowell EJ;Callegari EA;Malke H;Chaussee MS
化脓性链球菌外蛋白的产生，其中许多有助于毒力，是根据营养的可用性而调节的。CodY是一种转录调节因子，控制基因表达以响应氨基酸的可用性。本研究的目的是确定与codY基因缺失相关的链球菌外蛋白表达的差异。我们比较了野生型化脓性葡萄球菌与codY突变体在指数后生长阶段产生的分泌蛋白。我们使用了一维和二维凝胶电泳分离外蛋白。用串联质谱法鉴定了重复分析后丰度显著不同的蛋白质。codY突变体的上清液中分泌的半胱氨酸蛋白酶SpeB、分泌的染色体编码核酸酶（sadb）和推测的粘附因子（Spy49_0549）的产生更为丰富。此外，从codY突变株获得的上清液中，透明质酸酶（HylA）， CAMP因子（Cfa），噬菌体编码核酸酶（Spd-3）和未表征的细胞外蛋白（Spy49_0015）含量较少。酶分析显示，与野生型菌株相比，codY突变菌株在指数后生长阶段分离的培养上清中dna酶活性更高。由于细胞外核酸酶和蛋白酶可以影响生物膜的形成，我们还测量了菌株在富培养基（Todd Hewitt酵母提取物；THY）和化学定义培养基（CDM）生长期间形成生物膜的能力。与野生型相比，codY突变菌株在富培养基中形成的生物膜生物量没有差异，但在CDM中形成的生物膜生物量较少。总的来说，结果表明CodY改变了一组特定的化脓性葡萄球菌外蛋白的丰度，包括dna酶、蛋白酶和氢羟酸酶，这些外蛋白可能通过促进病原体向营养丰富的环境传播和水解宿主大分子来缓解饥饿。
The production of Streptococcus pyogenes exoproteins, many of which contribute to virulence, is regulated in response to nutrient availability. CodY is a transcriptional regulator that controls gene expression in response to amino acid availability. The purpose of this study was to identify differences in the expression of streptococcal exoproteins associated with deletion of the codY gene. We compared the secreted proteins produced by wild-type S. pyogenes to a codY mutant in the post-exponential phase of growth. We used both one and two-dimensional gel electrophoresis to separate exoproteins. Proteins that were significantly different in abundance upon repeated analysis were identified with tandem mass spectrometry. The production of the secreted cysteine protease SpeB, a secreted chromosomally encoded nuclease (SdaB), and a putative adhesion factor (Spy49_0549) were more abundant in supernatant fluids obtained from the codY mutant. In addition, hyaluronidase (HylA), CAMP factor (Cfa), a prophage encoded nuclease (Spd-3), and an uncharacterized extracellular protein (Spy49_0015) were less abundant in supernatant fluids obtained from the codY mutant strain. Enzymatic assays showed greater DNase activity in culture supernatants isolated in the post-exponential phase of growth from the codY mutant strain compared to the wild-type strain. Because extracellular nucleases and proteases can influence biofilm formation, we also measured the ability of the strains to form biofilms during growth with both rich medium (Todd Hewitt yeast extract; THY) and chemically defined media (CDM). No difference was observed with rich media but with CDM the biofilms formed by the codY mutant strain had less biomass compared to the wild-type strain. Overall, the results indicate that CodY alters the abundance of a select group of S. pyogenes exoproteins, including DNases, a protease, and hylauronidase, which together may alleviate starvation by promoting dissemination of the pathogen to nutrient rich environments and by hydrolysis of host macromolecules.
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