Related Experiment Video
Updated: Jul 28, 2026
07:27
Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
Published on: April 29, 2010
DNA synthesis at individual replication forks requires the essential initiation factor Cdc45p
J A Tercero1, K Labib, J F Diffley
1ICRF Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, UK.
The EMBO Journal
|May 3, 2000
Summary
Cdc45p is essential for DNA replication initiation and elongation in Saccharomyces cerevisiae. Its loss prevents DNA synthesis and blocks replication fork progression, highlighting its dual role in cell cycle progression.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Cdc45p is known to assemble at replication origins before initiation.
- Its precise role in DNA replication, particularly during elongation, requires further elucidation.
Purpose of the Study:
- To investigate the function of Cdc45p during both initiation and elongation phases of DNA replication.
- To determine the impact of Cdc45p loss on replication fork progression and cell cycle progression.
Main Methods:
- Construction of a heat-inducible cdc45 degron mutant in Saccharomyces cerevisiae.
- Analysis of DNA replication and cell cycle progression following Cdc45p depletion at restrictive temperatures.
- Utilizing density substitution techniques to track replication fork dynamics.
Main Results:
- Loss of Cdc45p in G1 phase completely inhibited DNA replication but allowed entry into mitosis.
- Depletion of Cdc45p during S-phase blocked S-phase completion without activating replication checkpoints.
- Cdc45p inactivation after replication fork establishment prevented individual fork progression, demonstrating a role in elongation.
Conclusions:
- Cdc45p plays a critical and essential role in both the initiation and elongation phases of chromosomal DNA replication.
- This study provides direct functional evidence for Cdc45p's involvement in replication fork progression.
- Cdc45p functions similarly to SV40 large T antigen in orchestrating DNA replication.
More Related Videos
Related Concept Videos
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
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.
01:02The DNA Replication Fork
An organism’s genome needs to be duplicated in an efficient and error-free manner for its growth and survival. The replication fork is a Y-shaped active region where two strands of DNA are separated and replicated continuously. The coupling of DNA unzipping and complementary strand synthesis is a characteristic feature of a replication fork. Organisms with small circular DNA, such as E. coli, often have a single origin of replication; therefore, they have only two replication forks, one in...
02:37Restarting Stalled Replication Forks
DNA replication is initiated at sites containing predefined DNA sequences known as origins of replication. DNA is unwound at these sites by the minichromosome maintenance (MCM) helicase and other factors such as Cdc45 and the associated GINS complex.The unwound single strands are protected by replication protein A (RPA) until DNA polymerase starts synthesizing DNA at the 5’ end of the strand in the same direction as the replication fork. To prevent the replication fork from falling apart, a...
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.