operon


operon
A genetic functional unit that controls production of a messenger RNA; it consists of an operator gene and two or more structural genes located in sequence in the cis position on one chromosome. [L. operor, to work, act, + -on]
- Lac o. a collection of adjacent bacterial genes responsible for the entry and metabolism of lactose; contains the genes coding for three enzymes and is flanked by a repressor and a promoter region to control expression.

* * *

op·er·on 'äp-ə-.rän n a group of closely linked genes that produces a single messenger RNA molecule in transcription and that consists of structural genes and regulating elements (as an operator and promoter)

* * *

n.
a group of closely linked genes that regulate the production of enzymes in bacteria. An operon is composed of one or more structural genes, which determine the nature of the enzymes made, and operator and promoter genes, which control the working of the structural genes. The operator is itself controlled by a regulator gene, which is not part of the operon.

* * *

op·er·on (opґər-on) [L. opera work + Gr. -on neuter ending] in prokaryotes, a chromosomal segment constituting a functional unit of transcription and so of genetic regulation. It comprises one or more structural genes, their promoter, and an operator region that through interaction with a regulator protein controls the structural genes.

Escherichia coli lac operon. In the absence of lactose, the product of the repressor gene binds the operator region and prevents transcription of genes involved in lactose utilization by blocking movement of the RNA polymerase from promoter to structural gene region; the operon is repressed. If lactose is added, an inducer binds the repressor protein, lessening its affinity for the operator. The RNA polymerase can then proceed from promoter to structural genes, so that the operon is derepressed, or expressed.


Medical dictionary. 2011.

Look at other dictionaries:

  • Operon — Opéron Un opéron est un groupement de gènes et de séquences régulatrices du génome des procaryotes chez qui cette organisation est principalement rencontrée. Les gènes concourent à la réalisation d une même fonction physiologique et sont… …   Wikipédia en Français

  • opéron — [ ɔperɔ̃ ] n. m. • 1961; de opérer ♦ Biol. Ensemble de gènes contigus sur le chromosome, dont les fonctions sont reliées et qui est une unité coordonnée de transcription régulée par un effecteur protéique. ● opéron nom masculin Groupe de gènes de …   Encyclopédie Universelle

  • operon — OPERÓN s.m. (biol.) Amsamblu de gene structurale a căror expresie fenotipică este controlată de un operator; unitate genetică a cărei expresie fenotipică este reglată de un represor. [< fr. opéron, it. operone]. Trimis de LauraGellner,… …   Dicționar Român

  • operon — operon. См. транскриптон. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • operón — (en biología molecular) segmento de ADN formado por un gen operador y uno o más genes estructurales con funciones relacionadas, controlado por el gen operador junto con un gen regulador. Diccionario ilustrado de Términos Médicos.. Alvaro Galiano …   Diccionario médico

  • Operon — Operon, mehrere Strukturgene umfassende Funktionseinheit in Protocyten, die ein gemeinsames mRNA Molekül bildet, deren Gene also entweder alle aktiv oder inaktiv sind und die unter der Kontrolle eines ⇒ Operators steht …   Deutsch wörterbuch der biologie

  • operon — opèrōn m <G operóna> DEFINICIJA biol. jedinstvo gena operatora i strukturnih gena kojima on upravlja; pod kontrolom je fizioloških stanja u staničnoj plazmi ETIMOLOGIJA lat. operator + on …   Hrvatski jezični portal

  • operon — [äp′ə rän΄] n. [< L operare, to work (see OPERATE) + ON] a cluster of genes, with related functions acting as a coordinated unit controlled by a regulatory gene …   English World dictionary

  • Operon — A typical operon In genetics, an operon is a functioning unit of genomic DNA containing a cluster of genes under the control of a single regulatory signal or promoter.[1][2] The genes are tr …   Wikipedia

  • Operón — Un Operón se define como una unidad genética funcional formada por un grupo o complejo de genes capaces de ejercer una regulación de su propia expresión por medio de los sustratos con los que interaccionan las proteínas codificadas por sus genes …   Wikipedia Español

  • operon — /op euh ron /, n. Genetics. a set of two or more adjacent cistrons whose transcription is under the coordinated control of a promoter, an operator, and a regulator gene. [1960 65; < F opéron, equiv. to opér(er) to work, OPERATE + on ON1] * * *… …   Universalium