Related Experiment Video
Updated: Jun 21, 2026
12:02
Studying Cell Cycle-regulated Gene Expression by Two Complementary Cell Synchronization Protocols
Published on: June 6, 2017
Divergent S phase checkpoint activation arising from prereplicative complex deficiency controls cell survival.
Eric Lau1, Gary G Chiang, Robert T Abraham
1The Burnham Institute for Medical Research, La Jolla, CA 92037, USA.
Molecular Biology of the Cell
|July 10, 2009
Summary
Depleting Cdc6, a protein crucial for DNA replication, halts normal cells but kills cancer cells by activating a DNA damage response. This suggests targeting Cdc6 could selectively eliminate tumors.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- The DNA replication machinery is vital for cell cycle progression.
- The specific roles of replication proteins in S phase checkpoint activation are not fully understood.
- The prereplicative complex (pre-RC) is essential for initiating DNA replication.
Purpose of the Study:
- To investigate the function of the pre-RC protein Cdc6 in cell cycle control.
- To determine the impact of Cdc6 depletion on normal and cancer cells.
- To elucidate the role of the ATR-dependent S phase checkpoint in response to pre-RC disruption.
Main Methods:
- Depletion of Cdc6 using specific reagents in human nontransformed diploid cells and cancer cell lines.
- Analysis of cell cycle progression (G1, S phase arrest).
- Assessment of S phase checkpoint activation and replication fork stability via ATR pathway monitoring.
Main Results:
- Cdc6 depletion caused nonlethal G1-G1/S and S phase arrest in normal cells.
- Cancer cell lines exhibited G1-G1/S arrest and cell death upon Cdc6 depletion.
- Differential activation of the ATR-dependent S phase checkpoint was observed, with compromised sensing in cancer cells.
- Chromatin alterations induced by pre-RC deficiency required higher replication stress to activate the checkpoint in cancer cells.
Conclusions:
- Cdc6 plays a critical role in regulating cell cycle progression and checkpoint control.
- Disruption of pre-RC function leads to distinct cellular responses in normal versus cancer cells.
- The ATR-dependent S phase checkpoint is differentially regulated in cancer cells, impacting their sensitivity to replication stress.
- Targeting pre-RC components like Cdc6 may offer a selective therapeutic strategy against cancer by exploiting compromised checkpoint mechanisms.
Related Concept Videos
02:38S-Cdk Initiates DNA Replication
The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
02:38S-Cdk Initiates DNA Replication
The cell cycle is a series of events leading to DNA duplication followed by the division of cell content to form two daughter cells. The cell cycle progresses in four stages—the cell increases in size (gap 1 or G1-phase), duplicates its DNA (synthesis or S-phase), prepares to divide (gap 2 or G2-phase), and divides (mitosis or M-phase).
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
Two states at the origin of replication
In eukaryotes, the initiation of replication occurs at many sites on the chromosomes, called the origins of replication.
01:28The Cell Cycle Control System
The cell cycle regulation directs how a cell proceeds from one phase to the next and begins mitosis. The cell cycle control system includes intracellular regulatory molecules and external triggers. They provide "stop" or "advance" signals and operate at specific cell cycle stages termed checkpoints to ensure that a particular process is completed before the cell advances to the next phase.
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and function at the cell...
Cyclins and cyclin-dependent kinases (Cdks) are the primary cell cycle regulators and function at the cell...
02:11The Cell Cycle Control System
The cell cycle is an organized set of events that leads the cell to divide into two daughter cells, each containing chromosomes identical to the parent cell. It is the cell cycle that leads to the formation of an entire organism from a single-cell zygote. Besides, cell division also functions in the renewal or repair of tissues in adult multicellular eukaryotes. For example, in the bone marrow, the stem cells divide to form new blood cells. Although essential for several functions, cell...
02:11The Cell Cycle Control System
The cell cycle is an organized set of events that leads the cell to divide into two daughter cells, each containing chromosomes identical to the parent cell. It is the cell cycle that leads to the formation of an entire organism from a single-cell zygote. Besides, cell division also functions in the renewal or repair of tissues in adult multicellular eukaryotes. For example, in the bone marrow, the stem cells divide to form new blood cells. Although essential for several functions, cell...
02:36DNA Damage can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...