Crucial role of Salmonella genomic island 1 master activator in the parasitism of IncC plasmids.
Crucial role of Salmonella genomic island 1 master activator in the parasitism of IncC plasmids.
复制标题
沙门氏菌基因组岛1主激活剂在IncC质粒寄生中的关键作用
DOI：
10.1093/nar/gkab204
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发表时间：
2021-08-20
影响因子：
14.9
通讯作者：
Burrus V
中科院分区：
文献类型：
--
作者：
Durand R;Huguet KT;Rivard N;Carraro N;Rodrigue S;Burrus V
IncC共轭质粒和沙门氏菌基因组岛1 （SGI1）的多变体是两个功能相互作用的移动遗传元件家族，通常与γ变形菌的多药耐药有关。SGI1及其兄弟基因被IncC共轭质粒特异动员。IncC质粒的共轭转移由质粒编码的主激活剂AcaCD激活。SGI1携带5个acacd响应启动子，驱动参与其切除、复制和动员的基因的表达。SGI1编码AcaCD同源物，即转录激活因子复合物SgaCD（也称为FlhDCSGI1），似乎可以识别和激活相同的SGI1启动子。在这里，我们研究了SGI1生命周期中SgaCD的相关性。配偶实验显示，SGI1的动员需要SgaCD和它的incc编码对应物AcaCD。ChIP-exo、capable -seq和RNA-seq结合的综合方法证实，SgaCD激活了18个acacd响应启动子中的每一个，驱动质粒转移功能的表达。通过报告基因分析，对SGI1的全套acacd应答启动子和辅助IncC质粒的活性进行了全面分析。qPCR和流式细胞术分析显示，SgaCD对于引发SGI1的切除和复制以及破坏辅助IncC质粒的稳定性至关重要。SGI1与其辅助质粒IncC之间的复杂调控串扰。
IncC conjugative plasmids and the multiple variants of Salmonella Genomic Island 1 (SGI1) are two functionally interacting families of mobile genetic elements commonly associated with multidrug resistance in the Gammaproteobacteria. SGI1 and its siblings are specifically mobilised in trans by IncC conjugative plasmids. Conjugative transfer of IncC plasmids is activated by the plasmid-encoded master activator AcaCD. SGI1 carries five AcaCD-responsive promoters that drive the expression of genes involved in its excision, replication, and mobilisation. SGI1 encodes an AcaCD homologue, the transcriptional activator complex SgaCD (also known as FlhDCSGI1) that seems to recognise and activate the same SGI1 promoters. Here, we investigated the relevance of SgaCD in SGI1′s lifecycle. Mating assays revealed the requirement for SgaCD and its IncC-encoded counterpart AcaCD in the mobilisation of SGI1. An integrative approach combining ChIP-exo, Cappable-seq, and RNA-seq confirmed that SgaCD activates each of the 18 AcaCD-responsive promoters driving the expression of the plasmid transfer functions. A comprehensive analysis of the activity of the complete set of AcaCD-responsive promoters of SGI1 and the helper IncC plasmid was performed through reporter assays. qPCR and flow cytometry assays revealed that SgaCD is essential to elicit the excision and replication of SGI1 and destabilise the helper IncC plasmid. Complex regulatory cross-talk between SGI1 and its helper IncC plasmid.