Systems biology for DNA cis-elements in circadian clockwork

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H03175
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 43030:Functional biochemistry-related
• Research Institution: Tokyo Metropolitan Institute of Medical Science (2020-2022); The University of Tokyo (2019)
• Principal Investigator: YOSHITANE Hikari 公益財団法人東京都医学総合研究所, 基礎医科学研究分野, 副参事研究員 (70569920)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 概日時計 / DNAシスエレメント / CRISPR-Cas9 / システムバイオロジー / 転写ネットワーク

Outline of Final Research Achievements

The E-box-mediated core feedback loop is interlocked with the RRE-mediated feedback loop, but biological significance of the RRE-mediated loop has been elusive. In this study, we established mutant cells and mice deficient for rhythmic transcription of Bmal1 gene by deleting its upstream RRE elements and hence disrupted the RRE-mediated feedback loop. We observed apparently normal circadian rhythms in the mutant cells and mice, but a combination of mathematical modeling and experiments revealed that the circadian period and amplitude of the mutants were more susceptible to disturbance of CRY1 protein rhythm. Our findings demonstrate that the RRE-mediated feedback regulation of Bmal1 underpins the E-box-mediated rhythm in cooperation with CRY1-dependent posttranslational regulation of BMAL1 protein, thereby conferring the perturbation-resistant oscillation and chronologically-organized output of the circadian clock.

Free Research Field

時間生物学

Academic Significance and Societal Importance of the Research Achievements

遺伝子そのものではなく、その転写制御配列をゲノム編集することにより、その転写制御の重要性を示すことができる、ということを証明した。Bmal1遺伝子は、遺伝子の欠損により時計振動は停止するが、その転写リズムを一定にしても時計振動は停止しなかった。このような研究戦略は、転写リズムを持つ遺伝子に対してのみならず、概日時計分野に限らず広い研究分野に対して、遺伝子そのものではなく、遺伝子の転写制御の意義を評価する上で、効果的であると期待される。