Mathematical Model for the Kai-Protein-Based Chemical Oscillator and Clock Gene Expression Rhythms in Cyanobacteria

In the cyanobacterium, Synechococcus elongatus, most promoters are regulated by a circadian clock under continuous light (LL) conditions. Nevertheless, the basic circadian oscillation is primarily generated by alternating KaiC phosphorylation/dephosphorylation reactions at the posttranslational leve...

Full description

Saved in:
Bibliographic Details
Published in:Journal of biological rhythms 2007-02, Vol.22 (1), p.69-80
Main Authors: Miyoshi, Fumihiko, Nakayama, Yoichi, Kaizu, Kazunari, Iwasaki, Hideo, Tomita, Masaru
Format: Article
Language:English
Subjects:
Bacterial Proteins - genetics
Bacterial Proteins - metabolism
Biological Clocks - genetics
Biological Clocks - physiology
Circadian rhythm
Circadian Rhythm - physiology
Circadian Rhythm Signaling Peptides and Proteins
Circadian rhythms
Clock gene
Computer Simulation
Coupling (molecular)
Cyanobacteria
Dephosphorylation
Elongation
Feedback
Gene expression
Gene Expression Regulation, Bacterial
Genetic aspects
In vitro methods and tests
Kinases
Mathematical models
Models, Biological
Molecular dynamics
Phosphorylation
Promoters
Protein interaction
Proteins
Robustness (mathematics)
Synechococcus - genetics
Synechococcus - physiology
Synechococcus elongatus
Transcription
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:In the cyanobacterium, Synechococcus elongatus, most promoters are regulated by a circadian clock under continuous light (LL) conditions. Nevertheless, the basic circadian oscillation is primarily generated by alternating KaiC phosphorylation/dephosphorylation reactions at the posttranslational level. Indeed, the KaiC phosphorylation cycle was recently reconstituted in vitro by incubating KaiA, KaiB, and KaiC proteins with ATP. However, the molecular dynamics of this chemical oscillation and the mechanism that drives the circadian transcription/translation rhythms remain unknown. In this report, the KaiC phosphorylation cycle and the gene regulatory network in the cyanobacterial circadian system have been modeled. The model reproduces the robust KaiC phosphorylation cycle in the absence of de novo gene expression as is observed in vitro, as well as its coupling to transcriptional/translational feedback in LL conditions in vivo. Moreover, the model is consistent with most previous experiments, including various combinations of genetic knockout or overexpression of kai genes. It also predicts that multiple KaiC phosphorylation states and dynamic Kai protein interactions may be required for the cyanobacterial circadian system.
ISSN:0748-7304
1552-4531
DOI:10.1177/0748730406295749