Circadian clocks are present in most eukaryotes and some prokaryotes and controlrhythms in behavior, physiology and gene expression. One well-characterized circadianclock is that of Neurospora crassa. In addition to the well-described N. crassaFRQ/WCC oscillator, several lines of evidence have implied the presence of otheroscillators which may have important functions in the N. crassa circadian clock system.However, the molecular details are only known for the core FRQ/WCC oscillator. Thelight mutant oscillator (LMO) was identified by two mutations (LM-1 and LM-2) andshown to control developmental rhythms in constant light (LL), conditions in which theFRQ/WCC oscillator is not functional. The objective of this project was to determinewhether the developmental rhythms driven by the LMO are circadian, whether thecomponents of the LMO communicate with components of the FRQ/WCC oscillator,and to begin to define the molecular nature of the LMO.First, the conditions for growth of the LM-1 mutant strain that reveals the best circadianrhythm of development in LL were found. Second, the LMO was determined to display the three properties required of a circadian oscillator. Third, the LMO was shown tofunction independently of the FRQ/WCC oscillator to control developmental rhythms inLL. However, evidence suggests that the FRQ/WCC oscillator and the LMOcommunicate with each other. Finally, using Cleaved Amplified Polymorphic Sequence(CAPS) markers, the LM-1 mutation was genetically mapped to the right arm of linkagegroup I within a 1069 kb region. Together, these results provide a start towardsunderstanding of the complexity of oscillators that form a circadian clock in organisms.
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