Baltazar-Cruz Jesús, Rojas-Rios Rogelio, Larios-Serrato Violeta, Mendoza-Sanchez Itza, Curiel-Quesada Everardo, Pérez-Valdespino Abigail
Department of Biochemistry, Escuela Nacional de Ciencias Biológicas del Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Col. Santo Tomás, Mexico City 11340, Mexico.
Department of Environmental & Occupational Health, Texas A&M University School of Public Health, College Station, TX 77843, USA.
Microorganisms. 2023 Oct 13;11(10):2548. doi: 10.3390/microorganisms11102548.
Integrons are genetic elements that store, express and exchange gene cassettes. These elements are characterized by containing a gene that codes for an integrase (I), a cassette integration site (I) and a variable region holding the cassettes. Using bioinformatics and molecular biology methods, a functional integron found in sp. 3925, a strain isolated from diarrheal stools, is described. To confirm the integron class, a phylogenetic analysis with amino acid sequences was conducted. The integrase was associated to class 4 integrases; however, it is clearly different from them. Thus, we classified the associated element as a class 4-like integron. We found that the integrase activity is not under the control of the SOS or catabolic repression, since the expression was not increased in the presence of mitomycin or arabinose. The class-4-like integron is located on the chromosome and contains two well-defined gene cassettes: A1 that confers resistance to streptomycin and coding for a lipoprotein. It also includes eight Open Reading frames (ORFs) with unknown functions. The strain was characterized through a Multilocus Phylogenetic Analyses (MLPA) of the B, A, D, A, J and X genes. The phylogenetic results grouped it into a different clade from the species already reported, making it impossible to assign a species. We resorted to undertaking complete genome sequencing and a phylogenomic analysis. sp. 3925 is related to and clusters, but it is clearly different from these species. In silico DNA-DNA hybridization (DDH) and Average Nucleotide Identity (ANI) analyses suggested that this isolate belongs to the genomospecies . This paper describes the first class 4-like integron in and contributes to the establishment of genomospecies
整合子是储存、表达和交换基因盒的遗传元件。这些元件的特征是含有一个编码整合酶（I）的基因、一个盒式整合位点（I）和一个容纳基因盒的可变区。利用生物信息学和分子生物学方法，描述了从腹泻粪便中分离出的菌株sp. 3925中发现的一个功能性整合子。为了确定整合子类别，对氨基酸序列进行了系统发育分析。该整合酶与4类整合酶相关；然而，它与它们明显不同。因此，我们将相关元件归类为类4整合子。我们发现整合酶活性不受SOS或分解代谢阻遏的控制，因为在丝裂霉素或阿拉伯糖存在下表达并未增加。类4整合子位于染色体上，包含两个明确的基因盒：赋予链霉素抗性并编码一种脂蛋白的A1。它还包括八个功能未知的开放阅读框（ORF）。通过对B、A、D、A、J和X基因的多位点系统发育分析（MLPA）对该菌株进行了表征。系统发育结果将其归入与已报道物种不同的进化枝，无法确定其物种。我们 resort to undertaking complete genome sequencing and a phylogenomic analysis. sp. 3925与 和 聚类相关，但它与这些物种明显不同。电子DNA-DNA杂交（DDH）和平均核苷酸同一性（ANI）分析表明该分离株属于基因组种 。本文描述了 中的首个类4整合子，并有助于基因组种的建立 。
（原文中“resort to undertaking complete genome sequencing and a phylogenomic analysis.”前少了一些词，翻译可能不太准确，可补充完整原文后再准确翻译。）
