Related Experiment Video
Updated: May 20, 2026
11:56
In Vitro Bioluminescence Assay to Characterize Circadian Rhythm in Mammary Epithelial Cells
Published on: September 28, 2017
CmpR is important for circadian phasing and cell growth.
Hiromitsu Tanaka1, Mai Kitamura, Yoko Nakano
1Department of Genome System Science, Graduate School of Nanobioscience, Yokohama City University, Seto 22-2, Kanazawa-ku, Yokohama 236-0027, Japan.
Plant & Cell Physiology
|June 30, 2012
Summary
Researchers identified CmpR as a regulator affecting the cyanobacteria circadian clock. CmpR influences pex gene expression and circadian rhythm phase, potentially through metabolic and redox status.
Area of Science:
- * Circadian biology
- * Molecular genetics
- * Cyanobacterial physiology
Background:
- * The cyanobacterium Synechococcus elongatus PCC 7942 utilizes a circadian clock synchronized by light/dark cycles.
- * The transcription factor Pex regulates the core circadian oscillator by repressing kaiA transcription, with its own expression increasing in darkness.
- * The regulatory mechanism controlling pex expression in response to darkness remained unelucidated.
Purpose of the Study:
- * To investigate the molecular mechanisms underlying the regulation of pex gene transcription in Synechococcus elongatus PCC 7942.
- * To identify genetic factors that influence pex expression and circadian rhythm.
- * To understand the role of CmpR in regulating pex and its impact on circadian timing and stress response.
Main Methods:
- * Construction of a pex expression bioluminescent reporter system.
- * Screening for mutants with altered luminescence via random insertion mutagenesis.
- * Molecular genetic analysis of identified mutants, including CmpR, flavodoxin, and ycf22, focusing on pex mRNA levels, circadian phase, and stress phenotypes.
- * In vitro DNA binding assays to assess CmpR's interaction with target promoters.
Main Results:
- * A mutant with an insertion in the CmpR locus exhibited a 1.8-fold increase in pex mRNA and a 5-hour delay in circadian peak phase.
- * CmpR-deficient cells displayed a high-light stress phenotype, which was complemented by ectopic gene induction.
- * A double cmpR/pex mutation partially suppressed the circadian phase abnormality observed in the cmpR mutant.
- * In vitro assays showed CmpR binds to the psbAII promoter but not to pex DNA.
Conclusions:
- * CmpR plays a role in regulating pex expression and circadian rhythm phase in Synechococcus elongatus PCC 7942.
- * The observed phenotypes in cmpR-deficient cells are likely due to impaired metabolic and/or redox status rather than direct transcriptional regulation of pex.
- * Further research is needed to fully elucidate the complex interplay between CmpR, metabolism, redox balance, and the circadian clock.
More Related Videos
Related Concept Videos
02:19Circadian Rhythms and Gene Regulation
The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
02:19Circadian Rhythms and Gene Regulation
The biological clock is involved in many aspects of regulating complex physiology in all animals. It was in 1935 when German zoologists, Hans Kalmus and Erwin Bünning, discovered the existence of circadian rhythm in Drosophila melanogaster. However, the internal molecular mechanisms behind the circadian clock remained a mystery until 1984, when Jeffrey C. Hall, Michael Rosbash, and Michael W. Young discovered the expression of the Per gene oscillating over a 24-hour cycle. In subsequent years,...
02:45Biological Clocks and Seasonal Responses
The circadian—or biological—clock is an intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles called circadian rhythms. Photoperiodism is a collective term for the biological responses of plants to variations in the relative lengths of dark and light periods. The period of light-exposure is called the photoperiod.
02:36Cells Coordinate Growth and Proliferation
Cell size is a significant factor impacting cellular design, function, and fitness. There exists some internal coordination by which cells double their masses before division, thus, achieving homeostasis. Coordination between cell growth and proliferation depends on the checkpoints in between cell cycle phases. Loss of coordination or failure in the checkpoint mechanism can drive the cell to uncontrolled growth and loss of cellular function. Like dividing cells that coordinate cellular growth,...
02:36Cells Coordinate Growth and Proliferation
Cell size is a significant factor impacting cellular design, function, and fitness. There exists some internal coordination by which cells double their masses before division, thus, achieving homeostasis. Coordination between cell growth and proliferation depends on the checkpoints in between cell cycle phases. Loss of coordination or failure in the checkpoint mechanism can drive the cell to uncontrolled growth and loss of cellular function. Like dividing cells that coordinate cellular growth,...
01:45Positive Regulator Molecules
To consistently produce healthy cells, the cell cycle—the process that generates daughter cells—must be precisely regulated.