Oligonucleotide: Definition, Function, and Examples

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Oligonucleotide Definition

Oligonucleotide is a short polymer made up of three to twenty nucleotide units, each of which contains a nucleobase, a sugar, and a phosphate group.

What is Oligonucleotide?

A nucleotide is the most fundamental component of nucleic acid polymers (e.g. DNA and RNA). A nucleobase (either a purine or a pyrimidine), a five-carbon sugar (pentose), and a phosphate group make up this chemical molecule. Ribose or deoxyribose can be found in the sugar component.

The sugar component of the nucleotides that make up RNA is called ribose sugar. DNA has a sugar component called deoxyribose. The sugar rings of two neighbouring nucleotide monomers are connected by each phosphate group.

The backbone of a nucleic acid is made up of phosphate groups and sugar moieties. The chain’s directionality goes from the 5′ end to the 3′ end. The two strands of DNA are oriented in opposing directions. This allows nucleobase components to pair with complimentary bases.

Nucleotides also come in cyclic forms, in addition to the lengthy chain of nucleic acids. When the phosphate group is connected twice to the sugar moiety, specifically to the two hydroxyl groups of the component sugar, cyclic nucleotides are formed.

Purines and pyrimidines are the two types of basic nucleotides. Adenine and guanine are frequent purine bases in DNA, while thymine and cytosine are common pyrimidine bases.

The chain is directed from the 5′ end to the 3′ end.The two strands of DNA are oriented opposite each other in DNA. To facilitate complementary base pairing between nucleobase components, this is done.

Nucleotides also come in cyclic forms in addition to the lengthy chain of nucleic acids. When the phosphate group is connected twice to the sugar moiety, especially the two hydroxyl groups of the component sugar, cyclic nucleotides are formed.

Purines and pyrimidines are two types of nucleotides that make up DNA. Adenine and guanine are the purine bases of DNA, whereas thymine and cytosine are the pyrimidine bases.

Oligonucleotide Characteristics

An oligonucleotide is a DNA molecule made up of three to twenty nucleotides. A nucleobase, a pentose moiety, and a phosphate group make up each monomeric unit component. Short DNA or RNA molecules are known as oligonucleotides.

They create a duplex when they attach to complementary oligonucleotides or nucleic acids. As a result, they’re utilised to check for the existence of nucleic acids.

Oligonucleotide Examples

Aptamers (from the Latin aptus (“-fit”) and Greek meros (“-part”), which are oligonucleotides (because other aptamers can be peptide molecules), are oligonucleotides that are mostly utilised for research and therapeutic purposes (e.g. as macromolecular drugs).

Aptamers have non-covalent interactions that allow them to attach to particular target locations. Aptamers are utilised for molecular recognition; they are sometimes chosen over antibodies because they can be designed and synthesised fully in vitro, with little or no immunogenicity.

DNA or RNA strands utilised in antisense treatment are known as antisense oligonucleotides. They have the ability to bind to the desired complementary sequence and therefore target particular RNAs.

Antisense oligonucleotides are used in antisense treatment to treat malignancies, diabetes, amyotrophic lateral sclerosis, Duchenne muscular dystrophy, asthma, arthritis, pouchitis, and other diseases.

Morpholino oligomers are used to manipulate gene expression. They can be used to disable a gene’s function. Understanding the function of a protein necessitates the use of gene knockdown.

Biological Importance of Oligonucleotide

In essence, oligomers have a role in gene expression control (e.g. microRNA). For usage in PCR (polymerase chain reaction), DNA sequencing, DNA microarrays, Southern blots, ASO analysis, FISH (fluorescent in situ hybridization), molecular probing, and library creation, oligomers are synthesised via solid-phase chemical synthesis.

Oligomers are utilised to detect the presence of DNA or RNA because they attach easily to nucleic acids. As a result, they’re mostly employed in forensics, genetic testing, and research. The use of oligomers in antisense treatment is also essential.

They are a brief sequence synthesised to match a location where a mutation is known to occur and then used as a probe in molecular genetics (oligonucleotide probes).

Oligonucleotide Citations
  • Safety of antisense oligonucleotide and siRNA-based therapeutics. Drug Discov Today . 2017 May;22(5):823-833.
  • Antisense Oligonucleotide Therapies for Neurodegenerative Diseases. Annu Rev Neurosci . 2019 Jul 8;42:385-406.
  • Advances in oligonucleotide drug delivery. Nat Rev Drug Discov . 2020 Oct;19(10):673-694.
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