Assignment of an essential role for the Neurospora frequency gene in circadian entrainment to temperature cycles
Year: 2005
Type: article
Abstract: Circadian systems include slave oscillators and central pacemakers, and the cores of eukaryotic circadian clocks described to date are composed of transcription and translation feedback loops (TTFLs). In the model system Neurospora, normal circadian rhythmicity requires a TTFL in which a White Collar complex (WCC) activates expression of the frequency (frq) gene, and the FRQ protein feeds back to attenuate that activation. To further test the centrality of this TTFL to the circadian mechanism in Neurospora, we used low-amplitude temperature cycles to compare WT and frq-null strains under conditions in which a banding rhythm was elicited. WT cultures were entrained to these temperature cycles. Unlike those normal strains, however, frq-null mutants did not truly entrain to the same cycles. Their peaks and troughs always occurred in the cold and warm periods, respectively, strongly suggesting that the rhythm in Neurospora lacking frq function simply is driven by the temperature cycles. Previous reports suggested that a FRQ-less oscillator (FLO) could be entrained to temperature cycles, rather than being driven, and speculated that the FLO was the underlying circadian-rhythm generator. These inferences appear to derive from the use of a phase reference point affected by both the changing waveform and the phase of the oscillation. Examination of several other phase markers as well as results of additional experimental tests indicate that the FLO is, at best, a slave oscillator to the TTFL, which underlies circadian rhythm generation in Neurospora.
Institutions: Dartmouth College, University of Manchester, Texas A&M University
Language: English
Subfield: Endocrine and Autonomic Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: bronze
Awards: Functional Analysis and Systems Biology of Filamentous Fungi, G2454876767, Genetic and Molecular Dissection of the Neurospora Clock, Molecular Genetic Analysis of Fungal Circadian Rhythms, G4398246120, Interaction of Light and Clock Regulation in Neurospora, Identification and Analysis of Clock Controlled Genes, G557880838, Coordination of Circadian Physiology of Diverse Species, Genetic and Molecular Dissection of the Neurospora Clock
OpenAlex ID: W2131949643