April 24, 2017
The term oligonucleotide comes from the Greek word “oligo,” meaning small or few. The length of the oligonucleotide is denoted by ‘mer’ (comes from Greek word Meros, which means part). Oligonucleotides are small DNA or RNA molecules (oligomers), which are widely applied in various fields like research, forensic science, polymerase chain reaction (PCR), library construction, artificial gene synthesis, DNA sequencing, genetic testing, molecular probing, DNA microarrays, southern blots, fluorescent in situ hybridization (FISH), antisense therapy, ASO analysis, etc. Oligonucleotides can be prepared in the laboratory by solid phase chemical synthesis
PCR assays and panels are designed to detect and quantify the expression of biologically related genes. They provide a detailed picture of metabolic processes, disease processes and signaling. The oligonucleotides are designed in such a way that the PCR amplicons can avoid regions consisting of SNPs and areas of cross homology and span introns where possible.
Antisense oligonucleotides reduce the amount of protein synthesis by reducing the processing or translation of mRNA . This approach is being used in many clinical trials for cancer treatment. Antisense therapy is being currently used for treatment of familial hypercholesterolemia and cytomegalovirus retinitis.
Fluorescence In Situ Hybridization (FISH) is used for detection and localization of RNA and DNA within cells and tissues of the body. Oligonucleotides which are used as probes have the following characteristics- they are 20 to 30 nucleotides long, they are often multiple and non overlapping, they are labeled at the ends of within itself multiple times to increase sensitivity, they are generally paired with fluorescent secondary antibodies when labeled with biotin or digoxigenin, they can be directly labeled with fluorescent dyes such as Cy3 , Cy5 etc.FISH is used extensively in clinical research and pathological studies.
Other common applications of oligonucleotide include nucleic acid aptamer design, allele specific oligonucletide testing and triplex forming oligonucleotides for binding of Ds DNA.
Disclaimer: The information given in this write-up is purely for educating the reader. It is not meant to be a substitute for any advice from a medical expert.