Molecular Biology of Archaea, Institute of Biology II-Microbiology, University of Freiburg, Freiburg, Germany.
Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia, USA.
mBio. 2020 Mar 10;11(2):e03014-19. doi: 10.1128/mBio.03014-19.
The UV-inducible pili system of (Ups) mediates the formation of species-specific cellular aggregates. Within these aggregates, cells exchange DNA to repair DNA double-strand breaks via homologous recombination. Substitution of the pilin subunits UpsA and UpsB with their homologs from showed that these subunits facilitate species-specific aggregation. A region of low conservation within the UpsA homologs is primarily important for this specificity. Aggregation assays in the presence of different sugars showed the importance of -glycosylation in the recognition process. In addition, the -glycan decorating the S-layer of is different from the one of Therefore, each species seems to have developed a unique UpsA binding pocket and unique glycan composition to ensure aggregation and, consequently, also DNA exchange with cells from only the same species, which is essential for DNA repair by homologous recombination. Type IV pili can be found on the cell surface of many archaea and bacteria where they play important roles in different processes. The UV-inducible pili system of (Ups) pili from the crenarchaeal species are essential in establishing species-specific mating partners, thereby assisting in genome stability. With this work, we show that different species have specific regions in their Ups pili subunits, which allow them to interact only with cells from the same species. Additionally, different species have unique surface-layer glycosylation patterns. We propose that the unique features of each species allow the recognition of specific mating partners. This knowledge for the first time gives insights into the molecular basis of archaeal self-recognition.
(ups) 的紫外线诱导菌毛系统介导了种特异性细胞聚集的形成。在这些聚集物中，细胞通过同源重组交换 DNA 来修复 DNA 双链断裂。用来自 的 pilin 亚基 upsA 和 upsB 的同源物替代它们表明这些亚基有助于种特异性聚集。upsA 同源物中保守性低的区域对这种特异性起主要作用。在存在不同糖的聚集测定中，显示了 -糖基化在识别过程中的重要性。此外， 中 S 层上的 -聚糖与 的不同。因此，每个 物种似乎都开发了独特的 upsA 结合口袋和独特的聚糖组成，以确保与仅来自同一物种的细胞聚集，这对于同源重组的 DNA 修复至关重要。IV 型菌毛可在许多古菌和细菌的细胞表面找到，在不同的过程中发挥着重要作用。来自古菌物种的紫外线诱导菌毛系统(ups)菌毛对于建立种特异性交配伙伴至关重要，从而有助于基因组稳定性。通过这项工作，我们表明不同的 物种在其 ups 菌毛亚基中具有特定区域，使它们只能与来自同一物种的细胞相互作用。此外，不同的 物种具有独特的表面层糖基化模式。我们提出，每个物种的独特特征允许识别特定的交配伙伴。这一知识首次揭示了古菌自我识别的分子基础。
