Department of Molecular Biology, Princeton University, Princeton, NJ 08544.
HHMI, Chevy Chase, MD 20815.
Proc Natl Acad Sci U S A. 2024 Nov 12;121(46):e2412642121. doi: 10.1073/pnas.2412642121. Epub 2024 Nov 5.
Quorum sensing (QS) is a cell-to-cell communication process that enables bacteria to coordinate group behaviors. In colonies, a program of spatial-temporal cell death is among the QS-controlled traits. Cell death occurs in two phases, first along the colony rim, and subsequently, at the colony center. Both cell death phases are driven by the type 6 secretion system (T6SS). Here, we show that HapR, the master QS regulator, does not control gene expression nor T6SS-mediated killing activity. Nonetheless, a Δ strain displays no cell death at the colony rim. RNA-Sequencing (RNA-Seq) analyses reveal that HapR activates expression of an operon containing four genes of unknown function, Epistasis and overexpression studies show that two of the genes, and , are required to drive cell death in both a Δ and a Δ Δ strain. Thus, - are regulated by HapR but act independently of the T6SS machinery to cause cell death, suggesting that a second, parallel pathway to cell death exists in .
群体感应（QS）是一种细胞间通讯过程，使细菌能够协调群体行为。在 菌 落中，时空细胞死亡程序是 QS 控制的特征之一。细胞死亡分两个阶段发生，首先沿菌 落 边缘，然后在菌 落 中心。这两个细胞死亡阶段都由 6 型分泌系统（T6SS）驱动。在这里，我们表明，QS 的主要调控因子 HapR 不控制 基因表达或 T6SS 介导的杀伤活性。尽管如此，Δ 株在菌 落 边缘没有细胞死亡。RNA 测序（RNA-Seq）分析显示，HapR 激活了一个包含四个未知功能基因的操纵子的表达，上位性和过表达研究表明，两个基因 和 对于驱动 Δ 和 Δ Δ 株中的细胞死亡是必需的。因此，- 由 HapR 调控，但独立于 T6SS 机制发挥作用导致细胞死亡，这表明在 中存在第二条平行的细胞死亡途径。
