title: Interconnections of reactive oxygen species homeostasis and circadian rhythm in Neurospora crassa.
abstract: CONCLUSIONS
  Both circadian rhythm and the production of reactive oxygen species (ROS) are fundamental features of aerobic eukaryotic cells. The circadian clock enhances the fitness of organisms by enabling them to anticipate cycling changes in the surroundings. ROS generation in the cell is often altered in response to environmental changes, but oscillations in ROS levels may also reflect endogenous metabolic fluctuations governed by the circadian clock. On the other hand, an effective regulation and timing of antioxidant mechanisms may be crucial in the defense of cellular integrity. Thus, an interaction between the circadian timekeeping machinery and ROS homeostasis or signaling in both directions may be of advantage at all phylogenetic levels.
  
  
  BACKGROUND
  The Frequency-White Collar-1 and White Collar-2 oscillator (FWO) of the filamentous fungus Neurospora crassa is well characterized at the molecular level. Several members of the ROS homeostasis were found to be controlled by the circadian clock, and ROS levels display circadian rhythm in Neurospora. On the other hand, multiple data indicate that ROS affect the molecular oscillator.
  
  
  RESULTS
  Increasing evidence suggests the interplay between ROS homeostasis and oscillators that may be partially or fully independent of the FWO. In addition, ROS may be part of a complex cellular network synchronizing non-transcriptional oscillators with timekeeping machineries based on the classical transcription-translation feedback mechanism.
  
  
  CONCLUSIONS
  Further investigations are needed to clarify how the different layers of the bidirectional interactions between ROS homeostasis and circadian regulation are interconnected.
authors: Department of Physiology, Semmelweis University , Budapest, Hungary .
authors: Norbert
authors: N
authors: Gyöngyösi
authors: Krisztina
authors: K
authors: Káldi
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000502:physiology*; D005656:Fungal Proteins / Q000502:physiology*; D006706:Homeostasis / Q000502:physiology*; D009492:Neurospora crassa / Q000502:physiology*; D018384:Oxidative Stress / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014157:Transcription Factors / Q000502:physiology*
chemical_list: D000975:Antioxidants; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D017382:Reactive Oxygen Species; D014157:Transcription Factors; C105589:wc-1 protein, Neurospora crassa; C103772:white collar 2 protein, Neurospora