Identification of the whole set of the constitutive promoters in Escherichia coli

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K06618
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 43050:Genome biology-related
• Research Institution: Meiji University
• Principal Investigator: Shimada Tomohiro 明治大学, 農学部, 専任准教授 (10535230)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: RNAポリメラーゼ / プロモーター / ゲノム転写制御 / シグマ因子RpoN / Repressive promoter / gSELEX法 / 大腸菌

Outline of Final Research Achievements

Gene expression is initiated when RNA synthetase (RNA polymerase) recognizes a specific sequence called a promoter, which is the transcription initiation site of a gene on the genome. For the RNA polymerase core enzyme in prokaryotes to recognize the promoter, it must bind to a subunit called the sigma factor to form a holoenzyme. As part of overall understanding of the mechanism of genome transcriptional regulation, we comprehensively analyzed the genomic promoter of the sigma factor RpoN holoenzyme and its enhancer NtrC to respond to nitrogen deprivation in E. coli and found that RNA polymerase, originally intended for gene expression, has a repressive effect on gene expression. Based on our findings, we propose a dual function for the RNAP RpoN holoenzyme, as a repressor (in the absence of NtrC) and as a NtrC-activated transcriptase. This repressor type of promoter was termed as a repressive promoter.

Free Research Field

ゲノム微生物学

Academic Significance and Societal Importance of the Research Achievements

RNAポリメラーゼRpoNホロ酵素が遺伝子発現に抑制的に作用することが明らかとなり、このプロモーターを「repressive promoter （抑圧的プロモーター）」と命名することを提案した。これまでにも、プロモーターの認識がRNAポリメラーゼホロ酵素単体で可能なものを「constitutive promoter（構成的プロモーター）」、何らかの補助因子が必要なものを「inducible promoter（誘導的プロモーター）」と呼ぶことを提案してきており、RNAポリメラーゼによりゲノムから利用される遺伝子が選択される仕組み、また、抑圧される仕組みの本質的な理解に役立つ成果となった。