Operon
Operon
An operon is a functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter. The genes are transcribed together into an mRNA strand and either translated together in the cytoplasm, or undergo splicing to create monocistronic mRNAs that are translated separately, i.e. several strands of mRNA that each encode a single gene product. The result of this is that the genes contained in the operon are either expressed together or not at all. Several operons are influenced by a repressor protein that inhibits mRNA synthesis.
History[edit | edit source]
The concept of the operon was first proposed in 1960 by François Jacob and Jacques Monod. Jacob and Monod were the first to discover the operon while studying the E. coli lac operon. They found out that the three structural genes lacZ, lacY, and lacA, are transcribed as a single unit, under the control of a single promoter and operator.
Structure[edit | edit source]
An operon contains one or more structural genes which are generally transcribed into one polycistronic mRNA (a single mRNA molecule that codes for multiple proteins). However, the definition of an operon does not require the mRNA to be polycistronic, though in practice, it usually is.
Function[edit | edit source]
The function of the operon is to regulate the efficient expression of genes according to the metabolic needs of the cell. If the products of the genes are required by the cell, the operon is switched on, allowing the genes to be expressed and the proteins to be produced. If the products are not required, the operon is switched off, and the genes are not expressed.
Types of Operons[edit | edit source]
There are two types of operons: inducible operons and repressible operons. Inducible operons are usually associated with catabolic pathways and are normally off, but can be turned on when the substrate that needs to be catabolized is present. Repressible operons are usually associated with anabolic pathways and are normally on, but can be turned off when the end product of the pathway is present in sufficient amounts.
See also[edit | edit source]
| Operon Resources | |
|---|---|
|
 |
Search WikiMD
Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD
|
WikiMD's Wellness Encyclopedia |
| Let Food Be Thy Medicine Medicine Thy Food - Hippocrates |
Translate this page: - East Asian
中文,
日本,
한국어,
South Asian
हिन्दी,
தமிழ்,
తెలుగు,
Urdu,
ಕನ್ನಡ,
Southeast Asian
Indonesian,
Vietnamese,
Thai,
မြန်မာဘာသာ,
বাংলা
European
español,
Deutsch,
français,
Greek,
português do Brasil,
polski,
română,
русский,
Nederlands,
norsk,
svenska,
suomi,
Italian
Middle Eastern & African
عربى,
Turkish,
Persian,
Hebrew,
Afrikaans,
isiZulu,
Kiswahili,
Other
Bulgarian,
Hungarian,
Czech,
Swedish,
മലയാളം,
मराठी,
ਪੰਜਾਬੀ,
ગુજરાતી,
Portuguese,
Ukrainian
Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.
Contributors: Prab R. Tumpati, MD
