Activation of TnSmu1, an integrative and conjugative element, by an ImmR-like transcriptional regulator in Streptococcus mutans.
Activation of TnSmu1, an integrative and conjugative element, by an ImmR-like transcriptional regulator in Streptococcus mutans.
复制标题
DOI：
10.1099/mic.0.001254
复制
发表时间：
2022-10
期刊：
影响因子：
2.8
通讯作者：
Shields, Robert C.
中科院分区：
文献类型：
--
作者：
King, Shawn;Quick, Allison;King, Kalee;Walker, Alejandro R.;Shields, Robert C.
整合和接合元件(ICES)是一种染色体编码的可移动遗传元件，可以在细菌菌株之间转移DNA。最近，作为确定假设基因功能的努力的一部分，我们发现了一个重要的调控模块，该模块编码在变形链球菌染色体上的一个被称为TnSmu1的ICE上。该调控模块包括一个带有螺旋-转角-螺旋DNA结合域的Ci类抑制物(ImmR SMU)和一个金属蛋白酶Imma SMU(抗抑制物)。不可能产生immR SMU的框内缺失突变体，并且用CRISPRi(CRISPR干扰)抑制immR SMU会导致大量细胞缺陷。我们使用了本质旁路(BoE)筛查来发现允许缺失调控模块的基因。这表明位于TnSmu1内的接合基因可以恢复immR SMU突变体的生存能力。ImmR SMU的缺失也会导致TnSmu1的环状中间体的产生，这也可以被遗传毒性药物丝裂霉素C诱导。为了进一步了解ImmRSmu1对TnSmu1的潜在调控以及对变形链球菌UA159的更广泛的生理影响，我们使用了CRISPRi和RNA-seq。强诱导基因包括所有TnSmu1移动元件、参与氨基酸代谢的基因、转运系统和I-C型CRISPR-Cas系统。生物信息学分析表明，TnSmu1移动元件及其相关基因在变形链球菌中分布良好。综上所述，我们的结果表明TnSmu1的激活是由immRA SMU模块控制的，而激活对变形链球菌是有害的，这突显了移动元件与其宿主之间的复杂相互作用。
Integrative and conjugative elements (ICEs) are chromosomally encoded mobile genetic elements that can transfer DNA between bacterial strains. Recently, as part of efforts to determine hypothetical gene functions, we have discovered an important regulatory module encoded on an ICE known as TnSmu1 on the Streptococcus mutans chromosome. The regulatory module consists of a cI-like repressor with a helix-turn-helix DNA binding domain immR Smu (immunity repressor) and a metalloprotease immA Smu (anti-repressor). It is not possible to create an in-frame deletion mutant of immR Smu and repression of immR Smu with CRISPRi (CRISPR interference) causes substantial cell defects. We used a bypass of essentiality (BoE) screen to discover genes that allow deletion of the regulatory module. This revealed that conjugation genes, located within TnSmu1, can restore the viability of an immR Smu mutant. Deletion of immR Smu also leads to production of a circular intermediate form of TnSmu1, which is also inducible by the genotoxic agent mitomycin C. To gain further insights into potential regulation of TnSmu1 by ImmRSmu and broader effects on S. mutans UA159 physiology, we used CRISPRi and RNA-seq. Strongly induced genes included all the TnSmu1 mobile element, genes involved in amino acid metabolism, transport systems and a type I-C CRISPR-Cas system. Lastly, bioinformatic analysis shows that the TnSmu1 mobile element and its associated genes are well distributed across S. mutans isolates. Taken together, our results show that activation of TnSmu1 is controlled by the immRA Smu module, and that activation is deleterious to S. mutans , highlighting the complex interplay between mobile elements and their host.
登录
查看更多内容
影响因子：
64.8
作者：
Beaber, JW;Hochhut, B;Waldor, MK
通讯作者：
Waldor, MK
影响因子：
28.3
作者：
Haag AF;Podkowik M;Ibarra-Chávez R;Gallego Del Sol F;Ram G;Chen J;Marina A;Novick RP;Penadés JR
通讯作者：
Penadés JR
影响因子：
3.7
作者：
Dmitriev A;Mohapatra SS;Chong P;Neely M;Biswas S;Biswas I
通讯作者：
Biswas I
影响因子：
4.4
作者：
Ahn, Sang-Joon;Rice, Kelly C.
通讯作者：
Rice, Kelly C.
影响因子：
3.2
作者：
Ahn, Sang-Joon;Burne, Robert A.
通讯作者：
Burne, Robert A.