Individual peroxiredoxin or Tor pathway components are not required for circadian clock function in Neurospora crassa

Abstract

In many model organisms, the circadian system has been proposed to comprise multiple oscillators that interact to promote accuracy of the clock as well as intricacies of rhythmic outputs. In Neurospora crassa, the circadian transcriptional/translational loop comprising of the FRQ (Frequency) and WCC (White Collar Complex) proteins has been instrumental in explaining many attributes of the clock including entrainment and rhythms in development and gene expression; in addition, some non-circadian oscillations can be unmasked when the FRQ-WCC feedback loop is eliminated. These rhythms have often lost defining circadian characteristics and are potentially controlled by other oscillators, termed FRQ-less oscillators (FLOs) in Neurospora. Understanding the biology of these oscillators and their hierarchical relationship with the FRQ-WCC oscillator (FWO) are salient questions in rhythms research. In this study, we examined candidate FLO effector pathways involving peroxiredoxins (Prxs) and mTOR. We find that independent gene knockouts compromising each pathway do not alter circadian period length or decrease the amplitude of the core circadian FWO rhythm in any meaningful way in Neurospora. Our findings suggest that molecular rhythms in Prx oxidation and in mTOR activity on the chol-1 FLO oscillator are neither required for nor strongly regulate FWO components during a normal circadian day.