Sanchez-Nieves Ruben L, Zhang Changyi, Whitaker Rachel J
Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, United States.
Department of Microbiology, University of Illinois Urbana-Champaign, Urbana, IL, United States.
Front Microbiol. 2023 Jan 23;14:1114574. doi: 10.3389/fmicb.2023.1114574. eCollection 2023.
Gene transfer in crenarchaea has been observed within natural and experimental populations of However, the molecular factors that govern how gene transfer and recombination manifest themselves in these populations is still unknown. In this study, we examine a plasmid-mediated mechanism of gene transfer in that results in localized high frequency recombination within the chromosome. Through chromosomal marker exchange assays with defined donors and recipients, we find that while bidirectional exchange occurs among all cells, those possessing the integrated conjugative plasmid, pM164, mobilize a nearby locus at a significantly higher frequency when compared to a more distal marker. We establish that is essential for this phenotype and that high frequency recombination can be replicated in transconjugants after plasmid transfer. Mapping recombinants through genomic analysis, we establish the distribution of recombinant tracts with decreasing frequency at increasing distance from pM164. We suggest the bias in transfer is a result of an Hfr (high frequency recombination)-like conjugation mechanism in this strain. In addition, we find recombinants containing distal non-selected recombination events, potentially mediated by a different host-encoded marker exchange (ME) mechanism.
在泉古菌的自然种群和实验种群中均已观察到基因转移现象。然而，在这些种群中，决定基因转移和重组如何表现的分子因素仍然未知。在本研究中，我们研究了嗜热栖热菌中一种由质粒介导的基因转移机制，该机制导致染色体内部发生局部高频重组。通过使用确定的供体和受体进行染色体标记交换试验，我们发现虽然所有细胞之间都会发生双向交换，但与更远端的标记相比，那些拥有整合型接合质粒pM164的细胞能以显著更高的频率动员附近的基因座。我们确定嗜热栖热菌对于这种表型至关重要，并且在质粒转移后，高频重组可以在接合子中复制。通过基因组分析对重组体进行定位，我们确定了重组片段的分布情况，即离pM164越远，重组频率越低。我们认为这种转移偏向是该菌株中一种类似高频重组（Hfr）的接合机制导致的结果。此外，我们发现了含有远端非选择重组事件的重组体，这些事件可能由一种不同的宿主编码标记交换（ME）机制介导。
