Clp ATPases differentially affect natural competence development in Streptococcus mutans.
Clp ATPases differentially affect natural competence development in Streptococcus mutans.
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作者：
在自然胜任的细菌中，通过水平基因转移的DNA转化是一种接受细胞外DNA的进化机制。细菌需要保持一种接受外来DNA的能力状态，这是一种受到严格控制的能量驱动现象。在链球菌中，能力发展是一个尚未完全了解的复杂过程。在这项研究中，我们使用变形链球菌，一种口腔细菌，来确定细胞密度如何影响能力发展。我们发现，在S. mutans中，当在低细胞密度下加入转化DNA并孵育2.5 h后选择转化子时，转化效率最高。我们还发现变形链球菌的细胞在对数中期之前仍然具有能力，之后能力急剧下降。令人惊讶的是，我们观察到Clp蛋白水解复合物的各个组分对能力的调节不同。如果在生长早期进行转化，则需要ClpP蛋白酶和ClpX atp酶来维持能力。相反，我们发现ClpC和ClpE对能力都有负向影响。我们还发现，如果转型是在中对数生长阶段进行的，那么能力仍然需要ClpX，但ClpP会对能力产生负向影响。虽然ClpP和ClpX对转化的这种差异影响的确切原因目前尚不清楚，但我们发现ClpC和ClpE对转化都有负面影响，这在以前没有报道过。细菌的自然能力发展受多种因素的调节，包括环境条件、营养物质的可用性和生长条件。变形链球菌，一种口腔细菌和龋齿的病原体，发展出天然的能力。这种细菌的能力发展过程尚不完全清楚。在这里，我们观察到突变链球菌保持几个小时的能力，这与其他链球菌相反。我们还观察到，由Clp蛋白编码的几种蛋白水解复合物对这种口腔链球菌的能力发育有差异调节，这些复合物通常是维持细胞蛋白质组所必需的。这有点令人惊讶，因为已知Clp蛋白水解复合物仅负向调节能力发展。这些新发现将为理解链球菌能力发展的调控开辟一条新的研究途径。
In naturally competent bacteria, DNA transformation through horizontal gene transfer is an evolutionary mechanism to receive extracellular DNA. Bacteria need to maintain a state of competence to accept foreign DNA, and this is an energy‐driven phenomenon that is tightly controlled. In Streptococcus, competence development is a complex process that is not fully understood. In this study, we used Streptococcus mutans, an oral bacterium, to determine how cell density affects competence development. We found that in S. mutans the transformation efficiency is maximum when the transforming DNA was added at low cell density and incubated for 2.5 h before selecting for transformants. We also found that S. mutans cells remain competent until the mid‐logarithmic phase, after which the competence decreases drastically. Surprisingly, we observed that individual components of Clp proteolytic complexes differentially regulate competence. If the transformation is carried out at the early growth phase, both ClpP protease and ClpX ATPase are needed for competence. In contrast, we found that both ClpC and ClpE negatively affect competence. We also found that if the transformation is carried out at the mid‐logarithmic growth phase ClpX is still required for competence, but ClpP negatively affects competence. While the exact reason for this differential effect of ClpP and ClpX on transformation is currently unknown, we found that both ClpC and ClpE have a negative effect on transformation, which was not reported before. Natural competence development in bacteria is modulated by several factors including environmental conditions, availability of nutrients, and growth conditions. Streptococcus mutans, an oral bacterium and the causative agent of dental caries, develops natural competence. The process of competence development in this bacterium is not fully understood. Here, we observed that S. mutants remains competent for several hours, which is in contrast to other streptococci. We also observed that several proteolytic complexes encoded by Clp proteins, which are generally needed for proper maintenance of cellular proteome, differentially regulate competence development in this oral streptococcal species. This is somewhat surprising since Clp proteolytic complexes are known to regulate competence development only negatively. These novel findings will potentially open a new avenue of research toward understanding the regulation of competence development in streptococci.
影响因子：
3.6
作者：
Federle MJ;Morrison DA
通讯作者：
Morrison DA