Oligonucleotide
Oligonucleotides are short sequences of
nucleotides (
RNA or
DNA), typically with twenty or fewer bases. Automated synthesizers allow the synthesis of oligonucleotides up to 160 to 200 bases. Oligonucleotides are often used as probes for detecting complementary DNA or RNA because they bind readily to their
complements. Examples of procedures that use oligonucleotides are
DNA microarrays,
Southern blots, and
fluorescent in situ hybridization (FISH). Oligonucleotides can also be used for the synthesis of artificial genes.
Oligonucleotides composed of DNA (deoxyoligonucleotides) are often used in the
polymerase chain reaction (PCR), a procedure that can be employed to amplify almost any piece of DNA. In this instance, the oligonucleotide is often referred to as a primer, or a short piece of DNA that binds to its complementary target sequence. This generates a place for a
polymerase to bind and extend the primer by the addition of
nucleotides to make a copy of the target sequence.
Oligonucleotides are often referred to as oligos, in "science slang".
Antisense oligonucleotides are single strands of DNA or RNA that are complementary to a chosen sequence. In the case of antisense RNA they prevent translation of complementary RNA strands by binding to it. Antisense DNA can be used to target a specific, complementary (coding or
non-coding) RNA. If binding takes places this DNA/RNA hybrid can be degraded by the enzyme
RNase H. Antisense oligonucleotides are being created to use on RNA that eventually produces telomerase, which is active in cancer cells.
One subtype of DNA MicroArrays can be described as substrates (nylon, glass etc.) to which oligonucleotides have been bound at high density. Currently there exist three applications of DNA MicroArrays: polymorphism studies, gene expression studies, and tracking down certain diseases.
Oligonucleotides, published by Mary Ann Liebert, Inc., is a peer-reviewed journal on natural or synthetic nucleic acid-based compounds such as oligonucleotides, RNA, ribozymes, RNAi, and aptamers and their biologic effects and applications both
in vitro and
in vivo. The clinical development of these agents, including toxicologic and pharmacologic issues are covered, as well as technology improvements and new applications of nucleic acids as tools or drugs, not only in the oligonucleotide field, but also in areas such as immune modulation or target validation.
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Amino acids are the building blocks of proteins. There are 20 natural amino acids.
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Antigen is a substance which, after take-up by an organism, elicits an immune response.
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Antibody is a protein produced by the immune system in order to protect the body against a foreign substance (antigen).
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Aptamer Oligonucleotides with important biological applications
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Chromosome*
DNA*
Epitope is the smallest part of an antigen that can be recognised by an antibody.
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Gene*
Morpholino oligos have non-natural backbones which do not activate RNase-H but can knockdown gene expression or modify splicing.
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Polymorphism The appearance in a population of the same gene in multiple forms because of mutations.
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Polynucleotide*
Recombinant DNA is DNA formed by the artificial combination of several exisiting DNA strands.
PIERCE, "GENETICS: A Conceptual Approach"2005
