{"title":"SbcB以不依赖外切酶的方式促进霍乱弧菌的自然转化。","authors":"Triana N Dalia, Ankur B Dalia","doi":"10.1128/jb.00419-24","DOIUrl":null,"url":null,"abstract":"<p><p>Natural transformation (NT) is a conserved mechanism of horizontal gene transfer in bacterial species. During this process, DNA is taken up into the cytoplasm where it can be integrated into the host genome by homologous recombination. We have previously shown that some cytoplasmic exonucleases inhibit NT by degrading ingested DNA prior to its successful recombination. However, one exonuclease, SbcB, counterintuitively promotes NT in <i>Vibrio cholerae</i>. Here, through a systematic analysis of the distinct steps of NT, we show that SbcB acts downstream of DNA uptake into the cytoplasm, but upstream of recombinational branch migration. Through mutational analysis, we show that SbcB promotes NT in a manner that does not rely on its exonuclease activity. Finally, we provide genetic evidence that SbcB directly interacts with the primary bacterial recombinase, RecA. Together, these data advance our molecular understanding of horizontal gene transfer in <i>V. cholerae</i> and reveal that SbcB promotes homologous recombination during NT in a manner that does not rely on its canonical exonuclease activity.</p><p><strong>Importance: </strong>Horizontal gene transfer by natural transformation contributes to the spread of antibiotic resistance and virulence factors in bacterial species. Here, we study how one protein, SbcB, helps facilitate this process in the facultative bacterial pathogen <i>Vibrio cholerae</i>. SbcB is a well-known for its exonuclease activity (i.e., the ability to degrade the ends of linear DNA). Through this study, we uncover that while SbcB is important for natural transformation, it does not facilitate this process using its exonuclease activity. Thus, this work helps further our understanding of the molecular events required for this conserved evolutionary process and uncovers a function for SbcB beyond its canonical exonuclease activity.</p>","PeriodicalId":15107,"journal":{"name":"Journal of Bacteriology","volume":" ","pages":"e0041924"},"PeriodicalIF":2.7000,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11784430/pdf/","citationCount":"0","resultStr":"{\"title\":\"SbcB facilitates natural transformation in <i>Vibrio cholerae</i> in an exonuclease-independent manner.\",\"authors\":\"Triana N Dalia, Ankur B Dalia\",\"doi\":\"10.1128/jb.00419-24\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Natural transformation (NT) is a conserved mechanism of horizontal gene transfer in bacterial species. During this process, DNA is taken up into the cytoplasm where it can be integrated into the host genome by homologous recombination. We have previously shown that some cytoplasmic exonucleases inhibit NT by degrading ingested DNA prior to its successful recombination. However, one exonuclease, SbcB, counterintuitively promotes NT in <i>Vibrio cholerae</i>. Here, through a systematic analysis of the distinct steps of NT, we show that SbcB acts downstream of DNA uptake into the cytoplasm, but upstream of recombinational branch migration. Through mutational analysis, we show that SbcB promotes NT in a manner that does not rely on its exonuclease activity. Finally, we provide genetic evidence that SbcB directly interacts with the primary bacterial recombinase, RecA. Together, these data advance our molecular understanding of horizontal gene transfer in <i>V. cholerae</i> and reveal that SbcB promotes homologous recombination during NT in a manner that does not rely on its canonical exonuclease activity.</p><p><strong>Importance: </strong>Horizontal gene transfer by natural transformation contributes to the spread of antibiotic resistance and virulence factors in bacterial species. Here, we study how one protein, SbcB, helps facilitate this process in the facultative bacterial pathogen <i>Vibrio cholerae</i>. SbcB is a well-known for its exonuclease activity (i.e., the ability to degrade the ends of linear DNA). Through this study, we uncover that while SbcB is important for natural transformation, it does not facilitate this process using its exonuclease activity. 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引用次数: 0
摘要
自然转化(NT)是细菌物种中一种保守的水平基因转移机制。在这一过程中,DNA 被带入细胞质,通过同源重组整合到宿主基因组中。我们之前已经证明,一些细胞质外切酶会在 DNA 成功重组之前降解摄入的 DNA,从而抑制 NT。然而,有一种外切核酸酶(SbcB)却反其道而行之,在霍乱弧菌中促进了NT。在这里,我们通过对 NT 的不同步骤进行系统分析,发现 SbcB 在 DNA 吸收到细胞质的下游,但在重组分支迁移的上游发挥作用。通过突变分析,我们发现 SbcB 促进 NT 的方式并不依赖于其外切酶活性。最后,我们提供了 SbcB 直接与主要细菌重组酶 RecA 相互作用的遗传学证据。这些数据共同推进了我们对霍乱弧菌水平基因转移的分子认识,并揭示了 SbcB 在 NT 过程中促进同源重组的方式并不依赖于其典型的外切酶活性:重要意义:通过自然转化进行的水平基因转移有助于细菌耐药性和毒力因子的传播。在这里,我们研究了一种蛋白质 SbcB 如何帮助促进面性细菌病原体霍乱弧菌的这一过程。SbcB 因其外切酶活性(即降解线性 DNA 末端的能力)而闻名。通过这项研究,我们发现虽然 SbcB 对自然转化很重要,但它并不能利用其外切酶活性促进这一过程。因此,这项工作有助于我们进一步了解这一保守的进化过程所需的分子事件,并发现 SbcB 在其典型的外切酶活性之外的功能。
SbcB facilitates natural transformation in Vibrio cholerae in an exonuclease-independent manner.
Natural transformation (NT) is a conserved mechanism of horizontal gene transfer in bacterial species. During this process, DNA is taken up into the cytoplasm where it can be integrated into the host genome by homologous recombination. We have previously shown that some cytoplasmic exonucleases inhibit NT by degrading ingested DNA prior to its successful recombination. However, one exonuclease, SbcB, counterintuitively promotes NT in Vibrio cholerae. Here, through a systematic analysis of the distinct steps of NT, we show that SbcB acts downstream of DNA uptake into the cytoplasm, but upstream of recombinational branch migration. Through mutational analysis, we show that SbcB promotes NT in a manner that does not rely on its exonuclease activity. Finally, we provide genetic evidence that SbcB directly interacts with the primary bacterial recombinase, RecA. Together, these data advance our molecular understanding of horizontal gene transfer in V. cholerae and reveal that SbcB promotes homologous recombination during NT in a manner that does not rely on its canonical exonuclease activity.
Importance: Horizontal gene transfer by natural transformation contributes to the spread of antibiotic resistance and virulence factors in bacterial species. Here, we study how one protein, SbcB, helps facilitate this process in the facultative bacterial pathogen Vibrio cholerae. SbcB is a well-known for its exonuclease activity (i.e., the ability to degrade the ends of linear DNA). Through this study, we uncover that while SbcB is important for natural transformation, it does not facilitate this process using its exonuclease activity. Thus, this work helps further our understanding of the molecular events required for this conserved evolutionary process and uncovers a function for SbcB beyond its canonical exonuclease activity.
期刊介绍:
The Journal of Bacteriology (JB) publishes research articles that probe fundamental processes in bacteria, archaea and their viruses, and the molecular mechanisms by which they interact with each other and with their hosts and their environments.