Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Via Vivaldi, 43, 81100 Caserta, Italy.
Institute of Biostructures and Bioimaging, CNR, Via Pietro Castellino, 80134 Naples, Italy.
Int J Mol Sci. 2023 Sep 29;24(19):14702. doi: 10.3390/ijms241914702.
Proteins of the MucR/Ros family play a crucial role in bacterial infection or symbiosis with eukaryotic hosts. MucR from plays a regulatory role in establishing symbiosis with the host plant, both dependent and independent of Quorum Sensing. Here, we report the first characterization of MucR isolated from by mass spectrometry and demonstrate that this protein forms higher-order oligomers in its native condition of expression by SEC-MALS. We show that MucR purified from can bind DNA and recognize the region upstream of the gene in EMSA, revealing that this gene is a direct target of MucR. Although MucR DNA binding activity was already described, a detailed characterization of DNA targets has never been reported. We, thus, analyze sequences recognized by MucR in the gene promoter, showing that this protein recognizes AT-rich sequences and does not require a consensus sequence to bind DNA. Furthermore, we investigate the dependence of MucR DNA binding on the length of DNA targets. Taken together, our studies establish MucR from as a member of a new family of Histone-like Nucleoid Structuring (H-NS) proteins, thus explaining the multifaceted role of this protein in many species of alpha-proteobacteria.
MucR/Ros 家族的蛋白在细菌感染或与真核宿主共生中起着至关重要的作用。 来自 的 MucR 在与宿主植物建立共生关系中发挥调节作用，这既依赖于群体感应，也独立于群体感应。 在这里，我们通过质谱法首次对 中分离出的 MucR 进行了表征，并证明了该蛋白在其天然表达状态下通过 SEC-MALS 形成更高阶的寡聚体。 我们表明，从 中纯化的 MucR 可以结合 DNA 并在 EMSA 中识别 基因上游区域，表明该基因是 MucR 的直接靶标。 尽管已经描述了 MucR 的 DNA 结合活性，但从未报道过 基因启动子中 的详细 DNA 靶标特征。 因此，我们分析了 MucR 在 基因启动子中识别的序列，表明该蛋白识别富含 AT 的序列，并且不需要保守序列即可结合 DNA。 此外，我们研究了 MucR DNA 结合对 DNA 靶标长度的依赖性。 综上所述，我们的研究确立了 中的 MucR 是一种新的组蛋白样核结构（H-NS）蛋白家族的成员，从而解释了该蛋白在许多α变形菌中的多种作用。
