Singh Harjeet, Pandya Shivani, Jasani Srushti, Patel Mitesh, Kaur Tanvir, Rustagi Sarvesh, Shreaz Sheikh, Yadav Ajar Nath
Narnarayan Shastri Institute of Technology-Institute of Forensic Science and Cyber Security (NSIT-IFSCS), Jetalpur, Ahmedabad, Gujarat, 382427, India.
Research for Development Cell, Parul University, Vadodara, Gujarat, 391760, India.
Antonie Van Leeuwenhoek. 2025 Jun 12;118(7):90. doi: 10.1007/s10482-025-02103-x.
Integrons, a diverse group of genetic elements, have emerged as key players in bacterial adaptation and evolution. These elements, commonly found in both environmental as well as clinical settings, facilitate the acquisition, exchange, and expression of integron cassettes, allowing bacteria to rapidly adapt to changing environments and acquire antibiotic resistance. This review provides an in-depth exploration of the various classes of clinical integrons, including class 1, 2, and 3, highlighting their origins, distribution, and associated mobile elements. We delve into the astonishing success of "class 1 integrons", emphasizing their ability to recognize diverse attachment sites known as "attC sites" and getting integrated within many different integron cassettes from diverse sources. Class 1 integrons are able to propagate widely among bacterial hosts due to their lack of host specificity, interaction with transposons, and broad host range plasmids. Moreover, we discuss the substantial impact of class 1 integrons in antimicrobial resistance, as they accumulate an array of resistance genes through strong positive selection. Additionally, we address the challenging issue regarding the evolution and function of integrons and integron cassettes, including the role of promoters, origins of integron cassettes, and the abundance of unknown proteins encoded within them. The future prospects of integron research are also explored, highlighting the need to understand cassette expression patterns, assess the contribution of chromosomal/superintegron arrays to host fitness, unravel the mechanisms of cassette generation, and investigate the connection between the SOS induction and horizontal gene transfer. Overall, this review underlines the significance of integrons as hidden architects driving bacterial adaptation and evolution, providing valuable insights into their ecological and evolutionary dynamics, and shaping the future direction of research in this field.
整合子是一类多样的遗传元件，已成为细菌适应和进化的关键因素。这些元件常见于环境和临床环境中，促进整合子盒的获取、交换和表达，使细菌能够快速适应不断变化的环境并获得抗生素耐药性。本综述深入探讨了各类临床整合子，包括1类、2类和3类，重点介绍了它们的起源、分布以及相关的移动元件。我们深入研究了“1类整合子”惊人的成功之处，强调了它们识别被称为“attC位点”的不同附着位点并整合到来自不同来源的许多不同整合子盒中的能力。1类整合子由于缺乏宿主特异性、与转座子相互作用以及具有广泛的宿主范围质粒，能够在细菌宿主中广泛传播。此外，我们讨论了1类整合子在抗菌耐药性方面的重大影响，因为它们通过强烈的正选择积累了一系列耐药基因。此外，我们还探讨了整合子和整合子盒的进化与功能这一具有挑战性的问题，包括启动子的作用、整合子盒的起源以及其中编码的大量未知蛋白质。我们还探讨了整合子研究的未来前景，强调需要了解盒式表达模式、评估染色体/超级整合子阵列对宿主适应性的贡献、揭示盒式产生的机制以及研究SOS诱导与水平基因转移之间的联系。总体而言，本综述强调了整合子作为驱动细菌适应和进化的隐藏架构师的重要性，为其生态和进化动态提供了有价值的见解，并塑造了该领域未来的研究方向。
