Escherichia Coli Replication Fork
Escherichia Coli Replication Fork - Related Videos
01:02
The DNA Replication Fork
0 Views •
2020
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...
01:02
The DNA Replication Fork
0 Views •
2023
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...
02:37
Restarting Stalled Replication Forks
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2020
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...
03:09
Fluorescently Tagged Repressor Protein-Mediated Replication Blockage in Escherichia coli
0 Views •
2025
Source: Mettrick, K. A., Lawrence, et al., Inducing a Site-Specific Replication Blockage in E. coli Using a Fluorescent Repressor Operator System. J. Vis. Exp. (2016)This video demonstrates site-specific replication fork blockage in Escherichia coli using arabinose-induced expression of yellow fluorescent protein-tagged TetR that binds chromosomal tetO arrays.
07:27
Direct Restart of a Replication Fork Stalled by a Head-On RNA Polymerase
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Cited by 10 •
2010
The fate of the replisome following a collision with a head-on RNA polymerase (RNAP) is unknown. We find that the replisome stalls upon collision with a head-on RNAP, but resumes elongation after displacing the RNAP from DNA. Mfd promotes replication restart by facilitating displacement of the RNAP after the collision.
FAQs
DnaB helicase separates the parental DNA strands, creating exposed templates for copying. Single-strand binding proteins stabilize these templates so they remain available for synthesis, while DnaG primase produces the RNA primers needed to begin DNA polymerase III activity. Their coordination links strand separation, template protection, and initiation, allowing replication to proceed efficiently at the fork.
The two DNA templates are copied differently at the fork. DNA synthesis on the leading strand proceeds continuously, whereas the lagging strand is produced as separate Okazaki fragments. These fragments provide a way to copy that template in the fork’s coordinated replication process, after which they are joined to create a continuous strand.
The fork combines rapid DNA unwinding with the production of new DNA on two differently organized templates. Any disruption in strand separation, template stabilization, primer formation, or fragment joining can interfere with coordinated copying. Studying these vulnerabilities helps explain how replication errors and fork damage can arise during bacterial chromosome duplication.
Accurate inheritance depends on coordinating parental-strand separation with primer formation and DNA synthesis on both templates. Continuous leading-strand production and discontinuous lagging-strand production must remain synchronized as the fork advances. When this organization functions properly, the chromosome can be duplicated in a form suitable for transmission to daughter cells.
A useful sequence begins with DnaB-mediated separation of the parental strands, followed by stabilization of the exposed templates by single-strand binding proteins. DnaG primase then supplies RNA primers for DNA polymerase III. Researchers can compare continuous leading-strand synthesis with lagging-strand Okazaki-fragment production to investigate how the replication machinery operates as a coordinated system.
The fork is essential for bacterial genome propagation, so its machinery provides a potential focus for antimicrobial strategies. Research can examine how disrupting helicase activity, template stabilization, primer synthesis, or the coordinated copying process affects chromosome replication. Such studies connect fork biology with efforts to interfere with bacterial growth and inheritance.