Neurospora, circadian rhythms

Experimental advances during the last decade have clarified the molecular bases of circadian rhythms, first in Drosophila and Neurospora, and more recently in cyanobacteria, plants, and mammals [95-99]. In nearly all cases investigated so far, it appears that circadian rhythms originate from the negative... 

Liu Y, Loros J, Dunlap JC 2000 Phosphorylation of the Neurospora clock protein FREQUENCY determines its degradation rate and strongly influences the period length of the circadian clock. Proc Natl Acad Sci USA 97 234—239 Loros JJ, Dunlap JC 2001 Genetic and molecular analysis of circadian rhythms in Neurospora. Annu Rev Physiol 63 757—794... 

The study of circadian rhythms has seen a clear acceleration in recent years owing to the combined insights provided by genetics and molecular biology (Feldman, 1982 Hall Rosbash, 1988 Takahashi, 1992, 1993 Dunlap, 1993 Takahashi et al, 1993 Young, 1993). Mutants of circadian rhythms were obtained in Drosophila as early as 1971 (see section 11.2). The use of circadian mutants, recently reviewed by Dunlap (1993), has also proved fruitful in Neurospora (see below) and rodents. Clock mutants have thus been obtained in the hamster (Ralph Menaker, 1988), and the mouse (Vitatema et al, 1994). 

Finally, negative feedback appears to play a prominent role in the molecular mechanism of circadian rhythms. As discussed further below, recent experiments in Drosophila and in Neurospora point to the existence of a negative feedback loop in which a key protein would repress the transcription of its gene. The best evidence in favour of such autoregulatory mechanism has been obtained for the per gene in Drosophila. Based on these observations, a theoretical model for circadian oscillations in per mRNA and PER protein was presented in chapter 11. 

Feldman, J.F. J.C. Dunlap. 1983. Neurospora crassa A unique system for studying circadian rhythms. Photochem. Photobiol Rev. 7 31S>-68. 

Lakin-Thomas, P.L., S. Brody G.G. Cote. 1991. Amplitude model for the effects of mutations and temperature on period and phase resetting of the Neurospora circadian oscillator. J. Biol. Rhythms 6 281-97. 

Sriram, K., Gopinathan, M.S. A two variable dealy model for the circadian rhythm of Neurospora crassa. J. Theor. Biol. 231, 23 (2004)... 

Lakin-Thomas, P.L., Cote, G.G., and Brody, S., Circadian rhythms in Neurospora crassa biochemistry and genetics, CRC Crit. Rev. Microbiol, 17, 365, 1990. 

Sargent ML, Briggs WR, Woodward DO 1966 Circadian nature of a rhythm expressed by an invertaseless strain of Neurospora crassa. Plant Physiol 41 1343—1349 Selby CP, Thompson C, Schmitz TM, Van Gelder RN, Sancar A 2000 Functional redundancy of cryptochromes and classical photoreceptors for nonvisual ocular photoreception in mice. Proc Natl Acad Sci USA 97 14697-14702... 

Loros, J.J., A. Lichens-Park, K.M. Lindgren J.C. Dunlap. 1993. Molecular genetics of genes under circadian temporal control in Neurospora. In Molecular Genetics of Biological Rhythms, M.W. Yoimg, ed. Marcel Dekker, New York, pp. 55-72. 

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