Faculty Opinions recommendation of Arabidopsis JMJD5/JMJ30 acts independently of LUX ARRHYTHMO within the plant circadian clock to enable temperature compensation.

2020 ◽  
Author(s):  
Alex Webb
Keyword(s):  
Circadian Clock ◽  
Temperature Compensation

scholarly journals Epistatic and Synergistic Interactions Between Circadian Clock Mutations in Neurospora crassa

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 537-543
Author(s):  
Louis W Morgan ◽  
Jerry F Feldman
Keyword(s):  
Circadian Clock ◽  
Neurospora Crassa ◽  
Mutant Strain ◽  
Temperature Compensation ◽  
Double Mutant ◽  
Synergistic Interactions ◽  
Long Period ◽  
Double Mutant Strain ◽  
Short Period ◽  
Compensation Mechanisms

Abstract We identified a series of epistatic and synergistic interactions among the circadian clock mutations of Neurospora crassa that indicate possible physical interactions among the various clock components encoded by these genes. The period-6 (prd-6) mutation, a short-period temperature-sensitive clock mutation, is epistatic to both the prd-2 and prd-3 mutations. The prd-2 and prd-3 long-period mutations show a synergistic interaction in that the period length of the double mutant strain is considerably longer than predicted. In addition, the prd-2 prd-3 double mutant strain also exhibits overcompensation to changes in ambient temperature, suggesting a role in the temperature compensation machinery of the clock. The prd-2, prd-3, and prd-6 mutations also show significant interactions with the frq7 long-period mutation. These results suggest that the gene products of prd-2, prd-3, and prd-6 play an important role in both the timing and temperature compensation mechanisms of the circadian clock and may interact with the FRQ protein.

scholarly journals Cross-scale Analysis of Temperature Compensation in the Cyanobacterial Circadian Clock System

2021 ◽  
Author(s):  
Yoshihiko Furuike ◽  
Dongyan Ouyang ◽  
Taiki Tominaga ◽  
Tatsuhito Matsuo ◽  
Atsushi Mukaiyama ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Temperature Compensation ◽  
Thermal Fluctuation ◽  
System Level ◽  
Dependent Manner ◽  
Clock System ◽  
Terminal Domain ◽  
Internal Motions ◽  
Clock Proteins ◽  
Quasielastic Neutron

Clock proteins maintain constant enzymatic activity regardless of temperature, even though thermal fluctuation is accelerated as temperature increases. We investigated temperature influences on the dynamics of KaiC, a temperature-compensated ATPase in the cyanobacterial circadian clock system, using quasielastic neutron scattering. The frequency of picosecond to sub-nanosecond incoherent local motions in KaiC was accelerated very slightly in a temperature-dependent manner. Our mutation studies revealed that internal motions of KaiC include several contributions of opposing temperature sensitivities. To take advantage of this balancing effect, the motional frequency of local dynamics in KaiC needs to exceed ~0.3 ps-1. Some of the mutation sites may be in a pathway through which the motional frequency in the C-terminal domain of KaiC is fed back to the active site of ATPase in its N-terminal domain. The temperature-compensating ability at the dynamics level is likely crucial for circadian clock systems, into which the clock proteins are incorporated, to achieve reaction- or even system-level temperature compensation of the oscillation frequency.

scholarly journals PERIOD phosphoclusters control temperature compensation of the Drosophila circadian clock

2021 ◽  
Author(s):  
Patrick Emery ◽  
Radhika Joshi ◽  
Yao Cai ◽  
Yomgliang Xia ◽  
Joanna Chiu
Keyword(s):  
Cell Culture ◽  
Circadian Clock ◽  
Temperature Compensation ◽  
Thermal Compensation ◽  
Functional Heterogeneity ◽  
Temperature Dependent ◽  
Critical Feature ◽  
Control Temperature ◽  
Functional Homolog

Temperature compensation is a critical feature of circadian rhythms, but how it is achieved remains elusive. Here, we uncovered the important role played by the Drosophila PERIOD (PER) phosphodegron in temperature compensation. Using CRISPR-Cas9, we introduced a series of mutations that altered three Serines (S44, 45 and 47) belonging to the PER phosphodegron, the functional homolog of mammalian PER2’s S487 phosphodegron, which impacts temperature compensation. While all three Serine to Alanine substitutions lengthened period at all temperatures tested, temperature compensation was differentially affected. S44A and S45A substitutions caused decreased temperature compensation, while S47A resulted in overcompensation. These results thus reveal unexpected functional heterogeneity of phosphodegron residues in thermal compensation. Furthermore, mutations impairing phosphorylation of the per^s phosphocluster decreased thermal compensation, consistent with its inhibitory role on S47 phosphorylation. Interestingly,the S47A substitution caused increased accumulation of hyper-phosphorylated PER at warmer temperatures. This finding was corroborated by cell culture assays in which S47A caused excessive temperature compensation of phosphorylation-dependent PER degradation. Thus, we show a novel role of the PER phosphodegron in temperature compensation through temperature-dependent modulation of the abundance of hyper-phosphorylated PER. Our work also reveals interesting mechanistic convergences and differences between mammalian and Drosophila temperature compensation of the circadian clock.

scholarly journals Mutation of a PER2 phosphodegron perturbs the circadian phosphoswitch

2020 ◽  
Vol 117 (20) ◽  
pp. 10888-10896 ◽  
Author(s):  
Shusaku Masuda ◽  
Rajesh Narasimamurthy ◽  
Hikari Yoshitane ◽  
Jae Kyoung Kim ◽  
Yoshitaka Fukada ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Messenger Rna ◽  
Temperature Compensation ◽  
Mrna Levels ◽  
Circadian Period ◽  
Embryonic Fibroblasts ◽  
Casein Kinase 1 ◽  
Ubiquitin E3 Ligase ◽  
Three Phase

Casein kinase 1 (CK1) plays a central role in regulating the period of the circadian clock. In mammals, PER2 protein abundance is regulated by CK1-mediated phosphorylation and proteasomal degradation. On the other hand, recent studies have questioned whether the degradation of the core circadian machinery is a critical step in clock regulation. Prior cell-based studies found that CK1 phosphorylation of PER2 at Ser478 recruits the ubiquitin E3 ligase β-TrCP, leading to PER2 degradation. Creation of this phosphodegron is regulated by a phosphoswitch that is also implicated in temperature compensation. However, in vivo evidence that this phosphodegron influences circadian period is lacking. Here, we generated and analyzed PER2-Ser478Ala knock-in mice. The mice showed longer circadian period in behavioral analysis. Molecularly, mutant PER2 protein accumulated in both the nucleus and cytoplasm of the mouse liver, while Per2 messenger RNA (mRNA) levels were minimally affected. Nuclear PER1, CRY1, and CRY2 proteins also increased, probably due to stabilization of PER2-containing complexes. In mouse embryonic fibroblasts derived from PER2-Ser478Ala::LUC mice, three-phase decay and temperature compensation of the circadian period was perturbed. These data provide direct in vivo evidence for the importance of phosphorylation-regulated PER2 stability in the circadian clock and validate the phosphoswitch in a mouse model.

scholarly journals Circadian Clock-Specific Roles for the Light Response Protein WHITE COLLAR-2

2001 ◽  
Vol 21 (8) ◽  
pp. 2619-2628 ◽  
Author(s):  
Michael A. Collett ◽  
Jay C. Dunlap ◽  
Jennifer J. Loros
Keyword(s):  
Circadian Clock ◽  
Temperature Compensation ◽  
Light Response ◽  
White Collar ◽  
Normal Activity ◽  
Relative Increase ◽  
Period Length ◽  
Mrna Levels ◽  
Temperature Dependent ◽  
Protein Levels

ABSTRACT To understand the role of white collar-2 in theNeurospora circadian clock, we examined alleles ofwc-2 thought to encode partially functional proteins. We found that wc-2 allele ER24 contained a conservative mutation in the zinc finger. This mutation results in reduced levels of circadian rhythm-critical clock gene products, frq mRNA and FRQ protein, and in a lengthened period of the circadian clock. In addition, this mutation altered a second canonical property of the clock, temperature compensation: as temperature increased, period length decreased substantially. This temperature compensation defect correlated with a temperature-dependent increase in overall FRQ protein levels, with the relative increase being greater in wc-2(ER24) than in wild type, while overall frq mRNA levels were largely unaltered by temperature. We suggest that this temperature-dependent increase in FRQ levels partially rescues the lowered levels of FRQ resulting from the wc-2 (ER24) defect, yielding a shorter period at higher temperatures. Thus, normal activity of the essential clock component WC-2, a positive regulator offrq, is critical for establishing period length and temperature compensation in this circadian system.

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