regulation of DNA-templated DNA replication

Definition

Target type: biologicalprocess

Any process that modulates the rate, frequency, or extent of DNA-templated DNA replication, the process in which new strands of DNA are synthesized. [GOC:dph, GOC:tb]

DNA-templated DNA replication is a highly regulated process that ensures the faithful duplication of the genome during cell division. This process is essential for the survival of all living organisms and involves a complex interplay of proteins and enzymes that coordinate the unwinding of the DNA helix, the synthesis of new DNA strands, and the proofreading of newly synthesized DNA.

**Initiation:**
* The process begins with the recognition of specific DNA sequences called origins of replication. These origins are typically rich in AT base pairs, which are easier to separate than GC base pairs.
* The origin recognition complex (ORC) binds to the origin and recruits other proteins, including Cdc6 and Cdt1, which help to load the helicase MCM2-7 onto the DNA.
* The MCM2-7 helicase is responsible for unwinding the DNA helix, creating a replication fork.

**Elongation:**
* Once the DNA is unwound, single-stranded DNA binding proteins (SSBs) bind to the single strands to prevent them from re-annealing.
* DNA polymerase α/primase synthesizes a short RNA primer on each strand, providing a starting point for DNA polymerase δ and ε to extend the DNA strands.
* DNA polymerase δ and ε use the parental DNA strands as templates to synthesize new complementary strands.
* The leading strand is synthesized continuously in the 5' to 3' direction.
* The lagging strand is synthesized discontinuously in short fragments called Okazaki fragments.
* DNA ligase joins the Okazaki fragments together.

**Termination:**
* Replication terminates when the two replication forks meet.
* The process involves specific sequences called termination sites that signal the end of replication.

**Regulation:**
* DNA replication is tightly regulated to ensure that the genome is replicated only once per cell cycle.
* Several mechanisms control the timing and fidelity of DNA replication, including:
* **Cell cycle checkpoints:** These checkpoints monitor the completion of specific steps in the replication process and prevent the initiation of DNA replication until the previous steps are completed.
* **Licensing factors:** These factors control the loading of the MCM2-7 helicase onto the origin and prevent the re-initiation of replication at the same origin.
* **DNA damage checkpoints:** These checkpoints stop replication if DNA damage is detected, allowing time for repair before replication continues.

**Fidelity:**
* DNA replication is highly accurate, with an error rate of less than one error per billion nucleotides.
* This accuracy is achieved through the proofreading activity of DNA polymerases and the action of DNA repair mechanisms.

**Conclusion:**
* DNA-templated DNA replication is a complex and essential process that ensures the faithful duplication of the genome during cell division.
* The regulation of this process is critical for maintaining genomic stability and ensuring the survival of organisms.'
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Proteins (1)

Compounds (2)