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oligonucleotide

 
Dictionary: ol·i·go·nu·cle·o·tide   (ŏl'ĭ-gō-nū'klē-ə-tīd, -nyū'-, ō'lĭ-) pronunciation
n.
A short polymer of two to twenty nucleotides.


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Sci-Tech Encyclopedia: Oligonucleotide
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A deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) sequence composed of two or more covalently linked nucleotides. Oligonucleotides are classified as deoxyribooligonucleotides or ribooligonucleotides. Fragments containing up to 50 nucleotides are generally termed oligonucleotides, and longer fragments are called polynucleotides.

A deoxyribooligonucleotide consists of a 5-carbon sugar called deoxyribose joined covalently to phosphate at the 5′ and 3′ carbons of this sugar to form an alternating, unbranched polymer. A ribooligonucleotide consists of a similar repeating structure where the 5-carbon sugar is ribose. Chemically synthesized oligonucleotides of predetermined sequence have proven to be very useful for studying a large number of biochemical processes. In the 1960s, these compounds were used to decipher the genetic code. Later, chemically prepared deoxyoligonucleotides were joined to form genes for transfer RNAs. Gene synthesis from synthetic deoxyoligonucleotides is now routinely used to prepare genes and modified genes for proteins having potential clinical applications. Oligonucleotides have also been used to diagnose genetic disorders and bacterial or viral infections. See also Nucleic acid.


Dental Dictionary: oligonucleotide
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n

A compound made up of the condensation of a small number of nucleotides.

Veterinary Dictionary: oligonucleotide
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A polymer made up of a few to a hundred or more nucleotides. Can be made synthetically to a specified sequence.

  • o. ligation assay — a technique for detecting a specific nucleotide pair in a gene.
Wikipedia: Oligonucleotide
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For the software see: OLIGO Primer Analysis Software.

An oligonucleotide is a short nucleic acid polymer, typically with twenty or fewer bases. Although they can be formed by bond cleavage of longer segments, they are now more commonly synthesized by polymerizing individual nucleotide precursors. Automated synthesizers allow the synthesis of oligonucleotides up to 160 to 200 bases.

The length of the oligonucleotide is usually denoted by "mer" (from Greek meros, "part"). For example, a fragment of 25 bases would be called a 25-mer. Because oligonucleotides readily bind to their respective complementary nucleotide, they are often used as probes for detecting DNA or RNA. Examples of procedures that use oligonucleotides include DNA microarrays, Southern blots, ASO analysis, fluorescent in situ hybridization (FISH), and the synthesis of artificial genes.

Oligonucleotides composed of DNA (oligodeoxyribonucleotides) are often used in the polymerase chain reaction, a procedure that can greatly amplify almost any small piece of DNA. There, the oligonucleotide is referred to as a primer, allowing DNA polymerase to extend the oligonucleotide and replicate the complementary strand.

Contents

Synthesis

Oligonucleotides are chemically synthesized using building blocks, protected phosphoramidites of natural or chemically modified nucleosides or, to a lesser extent, of non-nucleosidic compounds. The oligonucleotide chain assembly proceeds in the direction from 3'- to 5'-terminus by following a routine procedure referred to as a "synthetic cycle". Completion of a single synthetic cycle results in the addition of one nucleotide residue to the growing chain. A less than 100% yield of each synthetic step and the occurrence of side reactions set practical limits of the efficiency of the process so that the maximum length of synthetic oligonucleotides hardly exceeds 200 nucleotide residues. HPLC and other methods can be used to isolate products with the desired sequence

Antisense oligonucleotides

Antisense oligonucleotides are single strands of DNA or RNA that are complementary to a chosen sequence. In the case of antisense RNA they prevent protein translation of certain messenger RNA strands by binding to them. 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.

DNA microarray

One subtype of DNA microarrays can be described as substrates (nylon, glass, etc.) to which oligonucleotides have been bound at high density. There are a number of applications of DNA microarrays within the life sciences.

See also

  • Aptamer — oligonucleotides with important biological applications
  • Morpholino — oligos with non-natural backbones, which do not activate RNase-H but can reduce gene expression or modify RNA splicing
  • Polymorphism — the appearance in a population of the same gene in multiple forms because of mutations; can often be tested with ASO probes
  • Polynucleotide
  • CpG Oligodeoxynucleotide - an ODN with immunostimulatory properties

External links

References

  • Pierce, "GENETICS: A Conceptual Approach", 2005
  • Weiss, B. (ed.): Antisense Oligodeoxynucleotides and Antisense RNA : Novel Pharmacological and Therapeutic Agents, CRC Press, Boca Raton, FL, 1997
  • Weiss, B., Davidkova, G., and Zhou, L-W.: Antisense RNA gene therapy for studying and modulating biological processes. Cell. Mol. Life Sci., 55:334-358, 1999

 
 

 

Copyrights:

Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Sci-Tech Encyclopedia. McGraw-Hill Encyclopedia of Science and Technology. Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved.  Read more
Dental Dictionary. Mosby's Dental Dictionary. Copyright © 2004 by Elsevier, Inc. All rights reserved.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Oligonucleotide" Read more