Genetic interactions between clock mutations inNeurospora crassa: can they help us to understand complexity?

Abstract

Recent work on circadian clocks inNeurosporahas primarily focused on thefrequency(frq) andwhite–collar(wc) loci. However, a number of other genes are known that affect either the period or temperature compensation of the rhythm. These include theperiod(no relationship to theperiodgene ofDrosophila) genes and a number of genes that affect cellular metabolism. How these other loci fit into the circadian system is not known, and metabolic effects on the clock are typically not considered in single–oscillator models. Recent evidence has pointed to multiple oscillators inNeurospora, at least one of which is predicted to incorporate metabolic processes. Here, theNeurosporaclock–affecting mutations will be reviewed and their genetic interactions discussed in the context of a more complex clock model involving two coupled oscillators: a FRQ/WC–based oscillator and a ‘frq–less’ oscillator that may involve metabolic components.