Translesion Synthesis
Translesion Synthesis - Related Videos
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...
08:33
Hydrogel Synthesis
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2023
Source: Amber N. Barron, Ashlea Patterson, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT Hydrogels are a versatile class of cross-linked polymers produced through relatively simple procedures and with generally inexpensive materials. They can be formed from solution and involve a polymer backbone formed from monomer reagents, an initiator which makes the polymer reactive and a crosslinking species which binds the polymer chains...
09:42
Solid Phase Synthesis
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2023
Source: Vy M. Dong and Diane Le, Department of Chemistry, University of California, Irvine, CA Merrifield's solid-phase synthesis is a Nobel Prize winning invention where a reactant molecule is bound on a solid support and undergoes successive chemical reactions to form a desired compound. When the molecules are bound to a solid support, excess reagents and byproducts can be removed by washing away the impurities, while the target compound remains bound to the resin. Specifically, we will...
02:17
Synthesis and Decomposition Reactions
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2020
Synthesis and decomposition are two types of redox reactions. Synthesis means to make something, whereas decomposition means to break something. The reactions are accompanied by chemical and energy changes. Synthesis Reactions Synthesis reactions are also called combination reactions. It is a reaction in which two or more substances combine to form a complex substance. Synthesis reactions are generally represented as: A + B → AB or A + B → C. The formation of nitrogen dioxide is a synthesis...
02:36
Transfer RNA Synthesis
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2020
One of the unique features of tRNA is the presence of modified bases. In some tRNAs, modified bases account for nearly 20% of the total bases in the molecule. Altogether, these unusual bases protect the tRNA from enzymatic degradation by RNases. Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...
FAQs
At a stalled replication fork, TLS depends on a handoff from the normal replication machinery to a specialized polymerase. The specialized enzyme inserts a nucleotide opposite the damaged base or across another distortion, creating a temporary route past the obstruction. Once the lesion has been bypassed, replication can continue, linking lesion bypass to completion of genome duplication.
The key distinction is fidelity. Replicative polymerases normally copy DNA accurately, whereas TLS polymerases are recruited specifically when damage blocks that process and can insert nucleotides with lower accuracy. This trade-off allows synthesis to proceed past a lesion, but it also means that restarting replication may leave behind a mutation, affecting later genome stability.
The outcome reflects a balance between successful lesion bypass and the lower accuracy associated with specialized polymerases. When the damaged region is traversed and synthesis resumes, the cell can complete genome duplication and survive the damage. If nucleotide insertion is inaccurate, the same tolerance process can convert a temporary replication problem into a lasting mutation.
Useful endpoints include whether replication resumes after a damaged template is encountered, whether genome duplication is completed, and whether cells survive the damage. Researchers also need to consider mutation formation and overall genome stability, because successful bypass can preserve viability while still increasing the risk of copying errors.
TLS connects DNA damage with two contrasting consequences: cells may tolerate lesions well enough to continue genome duplication, yet error-prone bypass may introduce mutations. Examining that relationship helps biology research interpret how damage responses influence genome stability and disease mechanisms, without treating survival after damage as evidence that the underlying DNA sequence remained unchanged.
Cancer research can view TLS as a potential point for targeting DNA-damage responses. Its activity supports replication and survival after damage, while its lower accuracy can contribute to mutations. Studying that balance may help researchers consider strategies that alter damage tolerance or mutagenesis in cancer, although this represents a potential strategy rather than a defined treatment.