A global search for novel transcription factors impacting the Neurospora crassa circadian clock

• Published in: G3 : genes - genomes - genetics 2021-06, Vol.11 (6)
• Main Authors: Muñoz-Guzmán, Felipe, Caballero, Valeria, Larrondo, Luis F
• Format: Article
• Language: English
• Subjects: Circadian Clocks - genetics; Circadian Rhythm - genetics; Fungal Proteins - genetics; Fungal Proteins - metabolism; Mutant Screen Report; Neurospora crassa - metabolism; Transcription Factors - genetics; Transcription Factors - metabolism
• ISSN: 2160-1836; 2160-1836
• DOI: 10.1093/g3journal/jkab100

In order to identify new players modulating the circadian clock in the model Neurospora crassa, we adopted a reverse genetics strategy. Thus, we focused on transcription factors knockouts and crossed them to strains containing circadian luciferase reporters. Our screen covered close to 60% de the 302 genes encoding for such proteins in Neurospora, identifying that 23 of them appear to modulate period, while none of the tested ones (besides the classic core-clock components) are essential for daily rhythms.Abstract Eukaryotic circadian oscillators share a common circuit architecture, a negative feedback loop in which a positive element activates the transcription of a negative one that then represses the action of the former, inhibiting its own expression. While studies in mammals and insects have revealed additional transcriptional inputs modulating the expression of core clock components, this has been less characterized in the model Neurospora crassa, where the participation of other transcriptional components impacting circadian clock dynamics remains rather unexplored. Thus, we sought to identify additional transcriptional regulators modulating the N. crassa clock, following a reverse genetic screen based on luminescent circadian reporters and a collection of transcription factors (TFs) knockouts, successfully covering close to 60% of them. Besides the canonical core clock components WC-1 and -2, none of the tested transcriptional regulators proved to be essential for rhythmicity. Nevertheless, we identified a set of 23 TFs that when absent lead to discrete, but significant, changes in circadian period. While the current level of analysis does not provide mechanistic information about how these new players modulate circadian parameters, the results of this screen reveal that an important number of light and clock-regulated TFs, involved in a plethora of processes, are capable of modulating the clockworks. This partial reverse genetic clock screen also exemplifies how the N. crassa knockout collection continues to serve as an expedite platform to address broad biological questions.