Summary: A brief understanding of how radiolabeling is becoming outdated.
To identify the presence of an oligonucleotide they must be labeled. One form of labeling involves deoxyribonucleotide triphosphates through radioactive nuclei. This form of radioactive labeling utilizes the process of phosphorylation. The 3’end modification is through terminal transferase and the 5’-end modification is through phosphorylation.
One of the advantages of radiolabeling oligonucleotides is that there is a high level sensitivity involved within the process. On the downside, the disadvantages could possibly outweigh the good. Some negative aspects of radiolabeling include: reduced half-lives of certain nuclei, waste disposal issues, and expenses. Also, the kinase enzymes that are being labeled are only carried out on a very small scale, giving way to other labeling methods being preferred.
As a result, scientists use a different approach by applying a chemiluminescent or fluorescent label to the oligonucleotide. In many applications these forms of labeling have taken over and increased in popularity due to their advantages over radiolabeling.
When it comes to properly labeling an oligonucleotide or a DNA probe they must have certain properties to make them suitable for attachment. Dual-labeled probes are applicable to this as well. Labels should be easily detected when concentrations are at a low rate. Under non-weathered conditions, the label should be attached fairly easily under a simple and cheap protocol. Lastly, there should be the ability to detect different levels and differentiate each one with relative ease.
While the labeling process may seem arduous and confusing at first, this brief overview should help you understand the basics of oligonucleotide labeling.
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