title: Precise circadian clocks in prokaryotic cyanobacteria.
abstract: Prokaryotic cyanobacteria express robust circadian (daily) rhythms under the control of a timing mechanism that is independent of the cell division cycle. This biological clock orchestrates global regulation of gene expression and controls the timing of cell division. Proteins that may be involved in input pathways have been identified. Mutational screening has identified three clock genes that are organized as a gene cluster. The structure of cyanobacterial clock proteins, their phosphorylation, and regulation is described. A new model for the core clockwork in cyanobacteria proposes that rhythmic changes in the status of the chromosome underlie the rhythms of gene expression. Mixed-strain experiments demonstrate that this timekeeper confers adaptive value when different strains compete against each other.
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA. carl.h.johnson@vanderbilt.edu
authors.forename: Carl Hirschie
authors.initials: CH
authors.lastname: Johnson
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology*; D056925:Circadian Rhythm Signaling Peptides and Proteins; D000458:Cyanobacteria / Q000235:genetics / Q000502:physiology*; D008163:Luminescent Measurements; D013997:Time Factors
chemical_list: D001426:Bacterial Proteins; D056925:Circadian Rhythm Signaling Peptides and Proteins; C114269:KaiA protein, cyanobacteria; C114270:KaiB protein, cyanobacteria; C114271:KaiC protein, cyanobacteria