Regulation of pathogenicity through RNA degradation and processing by ribonuclease

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K15143
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 49050:Bacteriology-related
• Research Institution: University of Tsukuba
• Principal Investigator: Nozomu Obana 筑波大学, 医学医療系, 助教 (00722688)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: RNA / リボヌクレアーゼ / バイオフィルム / 温度応答 / 細胞外マトリクス / ウェルシュ菌

Outline of Final Research Achievements

Cells in biofilms dynamically adapt to surrounding environmental conditions, which alters biofilm architecture. The obligate anaerobic pathogen Clostridium perfringens shows different biofilm structures in different temperatures. Here we find that the temperature-regulated production of extracellular polymeric substance (EPS) is necessary for morphological changes in biofilms. We identify BsaA proteins as an EPS matrix necessary for pellicle biofilm formation at lower temperature. We show that bsaA operon is bimodal, and the bsaA-ON population size is increased at a lower temperature. We find that bsaA-ON cells cover bsaA-OFF cells attaching to the bottom surface. This heterogeneity is regulated by the cleavage of the pilA2 mRNA by RNase Y. As temperature is an environmental cue, C. perfringens may modulate EPS expression to induce morphological changes in biofilm structure as a strategy for adapting to interhost and external environments.

Free Research Field

分子微生物学

Academic Significance and Societal Importance of the Research Achievements

ウェルシュ菌は国内での患者数第3位の食中毒細菌であり、本菌が環境中に生残するメカニズムの解明は重要である。本菌は宿主の体温より低い温度に応答して自らを繊維状タンパク質（細胞外マトリクス）で覆い、強固な集団（バイオフィルム）を形成することで、酸素および抗生物質に対する耐性を向上させることを発見した。このバイオフィルム形成にはRNAの切断を介した遺伝子発現制御機構が必須であることを見出した。バイオフィルムマトリクスやRNA制御に着目したバイオフィルム除去法および食中毒や感染症の予防・治療法の開発が期待される。