Polymerase Delta
Polymerase Delta - Related Videos
01:17
The Delta-to-Delta Circuit
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2024
In a delta-delta configuration, the source and the load are connected in a delta manner, forming a closed loop that divides the network into three distinct phases. This configuration makes the phase voltages identical to line voltages. Assuming the sources are in positive sequence, the phase voltages can be expressed directly without having a neutral wire. The phase currents in a delta-connected load are calculated by dividing the phase voltage by the load impedance per phase: In this...
02:10
Translesion DNA Polymerases
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2020
Translesion (TLS) polymerases rescue stalled DNA polymerases at sites of damaged bases by replacing the replicative polymerase and installing a nucleotide across the damaged site. Doing so, TLS allows additional time for the cell to repair the damage before resuming regular DNA replication. TLS polymerases are found in all three domains of life - archaea, bacteria, and eukaryotes. Of the different classes of TLS polymerases, members of the Y family are fitted with specialized structures that...
05:47
Intravital Visualization of Gamma Delta Intraepithelial Lymphocytes
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2025
This video demonstrates the visualization of γδ intraepithelial lymphocytes (IELs) in transgenic mice using confocal microscopy. The surgical procedure involves creating a perforation line and making a longitudinal incision to expose the intestinal mucosa and villi. The transgenic mice express reporter proteins exclusively in γδ IELs, allowing their tracking. Intravital imaging captures the dynamic movement of green fluorescence-labeled γδ IELs along the intestinal epithelial cell's basement...
00:58
Eukaryotic RNA Polymerases
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2025
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action. All three eukaryotic RNAPs require specific transcription factors, of which the...
00:43
Bacterial RNA Polymerase
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2020
Unlike eukaryotes, bacteria use a single RNA Polymerase (RNAP) to transcribe all genes. The different subunits of bacterial RNAPhave distinct functions. The multisubunit structure of the bacterial RNAP helps the enzyme to maintain catalytic function, facilitate assembly, interact with DNA and RNA, and self-regulate its activity. In most genes, the transcription site is a single base present upstream of the coding sequence. Though RNAP is a catalytically efficient enzyme, it does not recognize...
FAQs
Polymerase Delta extends an existing RNA-DNA primer by adding nucleotides to the growing strand in the 5′-to-3′ direction. Its association with the sliding clamp PCNA supports processive synthesis, allowing the enzyme to remain engaged with DNA while extending the primer. This coordination is particularly important when completing discontinuous segments of the newly synthesized strand.
The 3′-to-5′ exonuclease activity provides proofreading during DNA synthesis. When an incorrect nucleotide is incorporated, this activity can remove many such errors before synthesis continues. By reducing copying mistakes at the point of replication, proofreading helps preserve the accuracy of genetic information and limits the accumulation of mutations that could contribute to genomic instability.
On the lagging strand, Polymerase Delta extends RNA-DNA primers to produce Okazaki fragments, which are short sections made during discontinuous DNA synthesis. Repeated primer extension enables the cell to copy this strand despite the directional constraints of DNA synthesis. The enzyme can also contribute to leading-strand replication, showing that its activity is not restricted to one replication context.
PCNA functions as a sliding clamp that works with Polymerase Delta during DNA synthesis. Its association with the polymerase supports processive extension, meaning the enzyme can continue copying DNA efficiently rather than disengaging after limited synthesis. This partnership is especially relevant to the repeated extension of primers during lagging-strand replication and Okazaki fragment formation.
Beyond genome duplication, Polymerase Delta contributes to DNA repair pathways. Its synthesis and proofreading activities help restore accurate DNA sequences when damaged or incorrectly copied regions require correction. This repair function connects polymerase activity with genome stability: effective repair helps preserve genetic information, whereas impaired replication or repair can increase mutations and broader genomic instability.
Studying defects in Polymerase Delta helps researchers examine how replication fidelity and DNA repair support stable genomes. Altered activity can be considered in relation to increased copying errors, mutations, and genomic instability, as well as disease-associated consequences. The complex therefore provides a useful biological context for connecting molecular DNA synthesis mechanisms with the preservation or disruption of genetic information.