Circadian rhythms in Neurospora crassa: Downstream effectors.
The circadian rhythm in Neurospora crassa is exhibited as alternating areas of conidiating and non-conidiating mycelia growth. A significant role in this circadian rhythm is played by the frq (frequency) and wc (white-collar) genes, comprising the "FWC" oscillator. Strains lacking the FWC can be restored to rhythmicity, which has been attributed to a second oscillator, called the FLO (frq-less oscillator). This study reports additional conditions that allow this rhythmicity to occur. Rhythmicity was restored to mutants lacking either the frq, or wc-1, or wc-2 genes in D/D (constant darkness) or L/L (constant light) by the addition of low levels of menadione, a known stimulator of ROS (reactive oxygen species). Additional studies are reported on the rhythm effects from caffeine, a known cAMP phospho-diesterase inhibitor as well as the effects from mutations in the csp-1 gene, the rco-1 gene, and other genes. A theme ties all of these "downstream effects" together, i.e., they affect either components thought to be part of the conidiation process itself, or the RAS-cAMP-protein kinase pathway. Since mutations in these components unexpectedly had rhythm effects, this suggests that these components may be good candidates for some part of the frq-less oscillator.
Brody
Stuart
S
Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093-0116, USA. sbrody@ucsd.edu
Oelhafen
Kim
K
Schneider
Kevin
K
Perrino
Sabrina
S
Goetz
Alexandra
A
Wang
Charlene
C
English
Carter
C
D002110:Caffeine / Q000494:pharmacology; D002940:Circadian Rhythm / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D008027:Light; D009154:Mutation; D009492:Neurospora crassa / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D024483:Vitamin K 3 / Q000494:pharmacology; D014815:Vitamins / Q000494:pharmacology
D004268:DNA-Binding Proteins; C087405:FRQ protein, Neurospora crassa; D005656:Fungal Proteins; D010726:Phosphodiesterase Inhibitors; C102112:RCO-1 protein, Neurospora crassa; D012097:Repressor Proteins; D014157:Transcription Factors; D014815:Vitamins; C105589:wc-1 protein, Neurospora crassa; C103772:white collar 2 protein, Neurospora; D002110:Caffeine; D024483:Vitamin K 3