ABSTRACT

The proliferation of antibiotic resistance has its origins in horizontal gene transfer. The class 1 integrons mediate gene transfer by assimilating antibiotic-resistance genes through site-specific recombination. For the class 1 integrons the first assimilated gene normally encodes an aminoglycoside antibiotic resistance protein which is either an aminoglycoside acetyltransferase (AAC), nucleotidyltransferase – (ANT), or adenyl transferase (AAD). An aminoglycoside-sensing riboswitch RNA in the leader RNA of AAC/AAD that controls the expression of aminoglycoside resistance genes has been previously described. Here we explore the relationship between the recombinant products of integron recombination and a series of candidate riboswitch RNAs in the 5ʹ UTR of aad (aminoglycoside adenyltransferases) genes. The RNA sequences from the 5ʹ UTR of the aad genes from pathogenic strains that are the products of site-specific DNA recombination by class 1 integrons were investigated. Reporter assays, MicroScale Thermophoresis (MST) and covariance analysis revealed that a functional aminoglycoside-sensing riboswitch was selected at the DNA level through integron-mediated site-specific recombination. This study explains the close association between integron recombination and the aminoglycoside-sensing riboswitch RNA.

摘要

抗生素抗性的扩散起源于水平基因转移。1类整合素通过位点特异性重组通过吸收抗生素抗性基因来介导基因转移。对于1类整合素，第一个同化基因通常编码一个氨基糖苷类抗生素抗性蛋白，该蛋白可以是氨基糖苷类乙酰基转移酶（AAC），核苷酸基转移酶–（ANT）或腺苷酸转移酶（AAD）。先前已经描述了控制氨基糖苷抗性基因表达的AAC / AAD的前导RNA中的氨基糖苷感测核糖开关RNA。这里，我们探讨整合重组的重组产品，并在5'UTR的一系列候选核糖开关的RNA之间的关系AAD（氨基糖苷腺苷酸转移酶）基因。研究了来自致病菌株的aad基因的5'UTR的RNA序列，这些基因是1类整合素进行位点特异性DNA重组的产物。记者分析，MicroScale Thermophoresis（MST）和协方差分析显示，通过整合子介导的位点特异性重组，在DNA水平上选择了功能性氨基糖苷敏感核糖开关。这项研究解释了整合子重组与氨基糖苷敏感的核糖开关RNA之间的紧密联系。