Expression of an Extracellular Protein (SMU.63) Is Regulated by SprV in Streptococcus mutans.
Expression of an Extracellular Protein (SMU.63) Is Regulated by SprV in Streptococcus mutans.
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变形链球菌中胞外蛋白 (SMU.63) 的表达受 SprV 调节。
DOI：
10.1128/aem.01647-20
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发表时间：
2020
影响因子：
4.4
通讯作者：
Biswas,Indranil
中科院分区：
文献类型：
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作者：
Pandey,SatyaDeo;Biswas,Indranil
在变形链球菌中，SprV（SMU. 2137）是一种多效性调节因子，其差异调节与感受态、变形蛋白产生、生物膜形成和胁迫耐受反应相关的基因，沿着一些其他途径。在这项研究中，我们建立了SprV和UA 159菌株的培养上清液中的一个67 kDa蛋白质之间的联系，该蛋白质后来通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）分析被确认为SMU.63。我们发现SprV下调SMU的转录和翻译。我们发现，来自SprV的C-末端区域的七个氨基酸对于SMU的表达也是至关重要的。缺失smu.63导致增加的蔗糖非依赖性生物膜形成和能力。prV缺失也增加了生物膜的形成，尽管这可能部分归因于smu的下调.在ansmu.63 sprV双突变体中，与对感受态发育的影响相反，在生物膜形成中观察到协同效应。我们发现，低或过量的镁离子抑制sprV转录，反过来，影响smu的表达。正如预期的那样，在UA 159菌株中观察到感受态和生物膜形成的镁离子依赖性效应。我们还复制了SMU.63在S. 63同源物，并发现GS 5菌株的行为类似于UA 159菌株，表明SprV的效果是菌株独立的。重要的是，我们以前确定了一个多效性调节，SprV，在变形链球菌。该调节因子在链球菌中似乎是高度保守的。在这里，我们发现SprV调节S.变异人已知SMU.63影响生物膜形成和遗传能力，这两个重要特征有助于生物体的定殖。SMU.63也是独特的，因为已知它形成淀粉样纤维。我们发现SprV在转录和翻译水平上调节SMU.63的表达。我们还发现SprV的表达受镁离子浓度的调节。有趣的是，低和高镁离子浓度影响生物膜的形成和遗传能力。由于SMU.63在链球菌中也是高度保守的，我们假设SprV对其表达也有类似的影响。
In Streptococcus mutans, SprV (SMU.2137) is a pleiotropic regulator that differentially regulates genes related to competence, mutacin production, biofilm formation, and the stress tolerance response, along with some other pathways. In this study, we established a link between SprV and an ∼67-kDa protein in the culture supernatant of strain UA159 that was later confirmed as SMU.63 by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) analysis. We discovered that SprV downregulates the transcription and translation of SMU.63. We found that the seven amino acids from the C-terminal region of SprV were also crucial for the expression of SMU.63. Deletion ofsmu.63led to increased sucrose-independent biofilm formation and competence. ThesprVdeletion also increased biofilm formation although this could be partially attributed to the downregulation ofsmu.63. In ansmu.63 sprVdouble mutant, a synergistic effect was observed in biofilm formation in contrast to effects on competence development. We found that low or excess magnesium ion repressedsprVtranscription that, in turn, affected the expression ofsmu.63. As expected, a magnesium ion-dependent effect of competence and biofilm formation was observed in the UA159 strain. We also replicated the results of SMU.63 expression and competence in S. mutans GS5 that encodes both SprV and SMU.63 homologs and found that the GS5 strain behaves similarly to the UA159 strain, indicating that SprV’s effect is strain independent.IMPORTANCEWe previously identified a pleiotropic regulator, SprV, in Streptococcus mutans. This regulator appears to be highly conserved among streptococci. Here, we showed that SprV regulates the expression of a secreted protein encoded by SMU.63 in S. mutans. SMU.63 has been known to impact biofilm formation and genetic competence, two important characteristics that help in colonization of the organism. SMU.63 is also unique since it is known to form amyloid fiber. We found that SprV regulates the expression of SMU.63 at both the transcriptional and translational levels. We also found that the expression of SprV is regulated by magnesium ion concentration. Interestingly, both low and high magnesium ion concentrations affected biofilm formation and genetic competence. Since SMU.63 is also highly conserved among streptococci, we hypothesized that SprV will have a similar effect on its expression.