본문 바로가기
HOME> 논문 > 논문 검색상세

논문 상세정보

Proceedings of the National Academy of Sciences of the United States of America v.114 no.4, 2017년, pp.E580 - E589   SCI SCIE
본 등재정보는 저널의 등재정보를 참고하여 보여주는 베타서비스로 정확한 논문의 등재여부는 등재기관에 확인하시기 바랍니다.

Redox crisis underlies conditional light–dark lethality in cyanobacterial mutants that lack the circadian regulator, RpaA

Diamond, Spencer (Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093 ); Rubin, Benjamin E. (Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093 ); Shultzaberger, Ryan K. (Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA 92093 ); Chen, You (Center for Circadian Biology, University of California, San Diego, La Jolla, CA 92093 ); Barber, Chase D. (Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093 ); Golden, Susan S. (Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093; );
  • 초록  

    Significance The evolution of photosynthetic cyanobacteria under 24-h cycles of light and darkness selected for a robust circadian clock. Understanding how cyanobacteria integrate circadian clock signals with natural light–dark cycles to control metabolism is critical, because these organisms are central to global carbon cycling and hold promise for development of renewable energy. Here we assess how the circadian transcription factor regulator of phycobilisome association A (RpaA) influences metabolism as a cyanobacterium goes through a light-to-dark transition. The data show that RpaA plays a key role in maintaining metabolic stability during the night period. Additionally, RpaA is important in controlling redox balance, which in turn is very important for regulating metabolism at night. Cyanobacteria evolved a robust circadian clock, which has a profound influence on fitness and metabolism under daily light–dark (LD) cycles. In the model cyanobacterium Synechococcus elongatus PCC 7942, a functional clock is not required for diurnal growth, but mutants defective for the response regulator that mediates transcriptional rhythms in the wild-type, regulator of phycobilisome association A (RpaA), cannot be cultured under LD conditions. We found that rpaA -null mutants are inviable after several hours in the dark and compared the metabolomes of wild-type and rpaA -null strains to identify the source of lethality. Here, we show that the wild-type metabolome is very stable throughout the night, and this stability is lost in the absence of RpaA. Additionally, an rpaA mutant accumulates excessive reactive oxygen species (ROS) during the day and is unable to clear it during the night. The rpaA- null metabolome indicates that these cells are reductant-starved in the dark, likely because enzymes of the primary nighttime NADPH-producing pathway are direct targets of RpaA. Because NADPH is required for processes that detoxify ROS, conditional LD lethality likely results from inability of the mutant to activate reductant-requiring pathways that detoxify ROS when photosynthesis is not active. We identified second-site mutations and growth conditions that suppress LD lethality in the mutant background that support these conclusions. These results provide a mechanistic explanation as to why rpaA -null mutants die in the dark, further connect the clock to metabolism under diurnal growth, and indicate that RpaA likely has important unidentified functions during the day.


  • 주제어

    cyanobacteria .   metabolism .   circadian clock .   metabolomics .   diurnal.  

 활용도 분석

  • 상세보기

    amChart 영역
  • 원문보기

    amChart 영역

원문보기

무료다운로드
유료다운로드

유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.

원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.

NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.

이 논문과 함께 출판된 논문 + 더보기