Shitut Shraddha, Bergman Güniz Özer, Kros Alexander, Rozen Daniel E, Claessen Dennis
Origins Centre, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
Institute of Biology, Leiden University, 2333 BE Leiden, The Netherlands.
Microorganisms. 2020 Nov 30;8(12):1897. doi: 10.3390/microorganisms8121897.
Filamentous actinobacteria are widely used as microbial cell factories to produce valuable secondary metabolites, including the vast majority of clinically relevant antimicrobial compounds. Secondary metabolites are typically encoded by large biosynthetic gene clusters, which allow for a modular approach to generating diverse compounds through recombination. Protoplast fusion is a popular method for whole genome recombination that uses fusion of cells that are transiently wall-deficient. This process has been applied for both inter- and intraspecies recombination. An important limiting step in obtaining diverse recombinants from fused protoplasts is regeneration of the cell wall, because this forces the chromosomes from different parental lines to segregate, thereby preventing further recombination. Recently, several labs have gained insight into wall-deficient bacteria that have the ability to proliferate without their cell wall, known as L-forms. Unlike protoplasts, L-forms can stably maintain multiple chromosomes over many division cycles. Fusion of such L-forms would potentially allow cells to express genes from both parental genomes while also extending the time for recombination, both of which can contribute to an increased chemical diversity. Here, we present a perspective on how L-form fusion has the potential to become a platform for novel compound discovery and may thus help to overcome the antibiotic discovery void.
丝状放线菌被广泛用作微生物细胞工厂，以生产有价值的次级代谢产物，包括绝大多数临床上相关的抗菌化合物。次级代谢产物通常由大型生物合成基因簇编码，这使得通过重组产生多种化合物的模块化方法成为可能。原生质体融合是一种用于全基因组重组的常用方法，它利用瞬时缺乏细胞壁的细胞进行融合。这个过程已应用于种间和种内重组。从融合的原生质体中获得多样重组体的一个重要限制步骤是细胞壁的再生，因为这会迫使来自不同亲本品系的染色体分离，从而阻止进一步的重组。最近，几个实验室对缺乏细胞壁但有能力增殖的细菌（即L型细菌）有了深入了解。与原生质体不同，L型细菌可以在许多分裂周期中稳定地维持多条染色体。这种L型细菌的融合可能使细胞能够表达来自双亲基因组的基因，同时也延长了重组时间，这两者都有助于增加化学多样性。在这里，我们阐述了L型细菌融合如何有可能成为新化合物发现的平台，从而可能有助于填补抗生素发现的空白。
