regulation of DNA strand elongation

Definition

Target type: biologicalprocess

Any process that modulates the rate, frequency or extent of DNA strand elongation. DNA strand elongation is the DNA metabolic process in which an existing DNA strand is extended by activities including the addition of nucleotides to the 3' end of the strand. [GOC:mah]

DNA strand elongation, the process of adding nucleotides to a growing DNA chain, is intricately regulated to ensure accurate and efficient replication. This regulation involves a complex interplay of factors, including:

**1. Initiation:**
* **Origin Recognition Complex (ORC):** Binds to specific DNA sequences (origins of replication) marking the starting point of replication.
* **Cdc6 and Cdt1:** These proteins recruit the MCM helicase to the origin, forming the prereplicative complex (pre-RC).
* **Cyclin-dependent kinases (CDKs):** Phosphorylate pre-RC components, triggering the activation of the origin.

**2. Elongation:**
* **DNA Helicase:** Unwinds the DNA double helix, separating the strands to provide templates for replication.
* **Single-stranded Binding Proteins (SSBs):** Stabilize the single-stranded DNA, preventing it from re-annealing.
* **DNA Polymerases:** Catalyze the addition of nucleotides to the growing DNA strand. DNA polymerase III is the primary polymerase responsible for elongation in E. coli.
* **Primase:** Synthesizes short RNA primers to initiate DNA synthesis, as DNA polymerase can only add nucleotides to a pre-existing 3' hydroxyl group.
* **Sliding Clamp:** Holds the DNA polymerase onto the DNA template, ensuring processivity.

**3. Termination:**
* **Specific Termination Sequences:** Signal the end of replication.
* **Tus Protein (in E. coli):** Binds to termination sequences and prevents helicase from unwinding further.

**4. Proofreading:**
* **DNA Polymerases:** Possess 3' to 5' exonuclease activity that allows them to remove mismatched nucleotides, enhancing replication accuracy.

**5. Checkpoint Control:**
* **Checkpoint Proteins:** Monitor the replication process and arrest cell cycle progression if errors are detected, ensuring genomic integrity.

**6. Regulation of Replication Origin Activation:**
* **Licensing Factor (MCM):** Only one replication origin is activated per cell cycle, preventing re-replication.
* **Cdk-mediated Phosphorylation:** Activates the origin, while also inhibiting origin licensing in the next cycle.

**7. Nucleosome Assembly:**
* **Histones:** After replication, new DNA strands are wrapped around histone proteins, forming nucleosomes, restoring the chromatin structure.

The regulation of DNA strand elongation is essential for maintaining genomic integrity and ensuring proper cell function. Any errors in this process can lead to mutations, DNA damage, and potentially disease.'
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Proteins (3)

Compounds (6)