Search results
Results from the WOW.Com Content Network
The lac operon of the model bacterium Escherichia coli was the first operon to be discovered and provides a typical example of operon function. It consists of three adjacent structural genes, a promoter, a terminator, and an operator. The lac operon is regulated by several factors including the availability of glucose and lactose.
The lactose operon (lac operon) is an operon required for the transport and metabolism of lactose in E. coli and many other enteric bacteria.Although glucose is the preferred carbon source for most enteric bacteria, the lac operon allows for the effective digestion of lactose when glucose is not available through the activity of β-galactosidase. [1]
Genetic regulatory circuits (also referred to as transcriptional regulatory circuits) is a concept that evolved from the Operon Model discovered by François Jacob and Jacques Monod. [1] [2] [3] They are functional clusters of genes that impact each other's expression through inducible transcription factors and cis-regulatory elements. [4] [5]
The Lac operon is an interesting example of how gene expression can be regulated. Viruses, despite having only a few genes, possess mechanisms to regulate their gene expression, typically into an early and late phase, using collinear systems regulated by anti-terminators (lambda phage) or splicing modulators .
A structural gene is a gene that codes for any RNA or protein product other than a regulatory factor (i.e. regulatory protein).A term derived from the lac operon, structural genes are typically viewed as those containing sequences of DNA corresponding to the amino acids of a protein that will be produced, as long as said protein does not function to regulate gene expression.
The transcription of an operon's mRNA is often controlled by a repressor that can occur in an active or inactive state depending on the presence of specific metabolites. [65] When active, the repressor binds to a DNA sequence at the beginning of the operon, called the operator region , and represses transcription of the operon ; when the ...
The gal operon contains two operators, O E (for external) and O I (for internal). The former is just upstream of the promoter, and the latter is just after the galE gene (the first gene in the operon). These operators bind the repressor, GalR, which is encoded from outside the operator region. For this repressor protein to function properly ...
The Histidine operon leader is an RNA element found in the bacterial histidine operon. At least 6 amino acid operons are known to be regulated by attenuation . [ 1 ] In each a leader sequence of 150–200 bp is found upstream of the first gene in the operon.