Toxin–antitoxin (TA) systems are ubiquitous among bacteria and include stable toxins whose toxicity can be counteracted by RNA or protein antitoxins. They are involved in multiple functions that range from stability maintenance for mobile genetic elements to stress adaptation. Bacterial chromosomes frequently have multiple homologues of TA system loci, and it is unclear why there are so many of them. In this review we focus on cross-regulations between TA systems, which occur between both homologous and nonhomologous systems, from similar or distinct types, whether encoded from plasmids or chromosomes. In addition to being able to modulate RNA expression levels, cross-regulations between these systems can also influence their toxicity. This suggests the idea that they are involved in an interconnected regulatory network.

毒素-抗毒素（TA）系统在细菌中普遍存在，包括稳定的毒素，其毒性可以被RNA或蛋白质抗毒素抵消。它们涉及多种功能，从移动遗传元件的稳定性维护到压力适应。细菌染色体经常具有TA系统基因座的多个同源物，目前尚不清楚为什么它们如此之多。在这篇综述中，我们着重于TA系统之间的交叉调节，这种交叉调节发生在同源或非同源系统之间，无论是相似类型还是不同类型，无论是质粒还是染色体编码。除了能够调节RNA表达水平外，这些系统之间的交叉调节也会影响其毒性。这表明他们参与了互连的监管网络。