A genetic selection for circadian output pathway mutations in Neurospora crassa. Academic Article uri icon


  • In most organisms, circadian oscillators regulate the daily rhythmic expression of clock-controlled genes (ccgs). However, little is known about the pathways between the circadian oscillator(s) and the ccgs. In Neurospora crassa, the frq, wc-1, and wc-2 genes encode components of the frq-oscillator. A functional frq-oscillator is required for rhythmic expression of the morning-specific ccg-1 and ccg-2 genes. In frq-null or wc-1 mutant strains, ccg-1 mRNA levels fluctuate near peak levels over the course of the day, whereas ccg-2 mRNA remains at trough levels. The simplest model that fits the above observations is that the frq-oscillator regulates a repressor of ccg-1 and an activator of ccg-2. We utilized a genetic selection for mutations that affect the regulation of ccg-1 and ccg-2 by the frq-oscillator. We find that there is at least one mutant strain, COP1-1 (circadian output pathway derived from ccg-1), that has altered expression of ccg-1 mRNA, but normal ccg-2 expression levels. However, the clock does not appear to simply regulate a repressor of ccg-1 and an activator of ccg-2 in two independent pathways, since in our selection we identified three mutant strains, COP1-2, COP1-3, and COP1-4, in which a single mutation in each strain affects the expression levels and rhythmicity of both ccg-1 and ccg-2.

published proceedings

  • Genetics

altmetric score

  • 6.232

author list (cited authors)

  • Vitalini, M. W., Morgan, L. W., March, I. J., & Bell-Pedersen, D.

citation count

  • 16

complete list of authors

  • Vitalini, Michael W||Morgan, Louis W||March, Irene J||Bell-Pedersen, Deborah

publication date

  • May 2004