Search results
Results from the WOW.Com Content Network
The repressor is shown in complex with operator DNA (gold) and ONPF (green), an anti-inducer ligand (i.e. a stabilizer of DNA binding) The lac repressor (LacI) is a DNA-binding protein that inhibits the expression of genes coding for proteins involved in the metabolism of lactose in bacteria. These genes are repressed when lactose is not ...
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]
The T7 gene is itself under the control of a lac promoter. Normally, both the lac promoter and the T7 promoter are repressed in the E. coli cell by the Lac repressor. In order to initiate transcription, an inducer must bind to the lac repressor and prevent it from inhibiting the gene expression of the T7 gene. Once this happens, the gene can be ...
Illustration of an activator. In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. [ 1 ][ 2 ] The function of TFs is to regulate—turn on and off—genes in order ...
Repressilator. The repressilator is a genetic regulatory network consisting of at least one feedback loop with at least three genes, each expressing a protein that represses the next gene in the loop. [ 1] In biological research, repressilators have been used to build cellular models and understand cell function.
Up-regulation is a process which occurs within a cell triggered by a signal (originating internal or external to the cell), which results in increased expression of one or more genes and as a result the proteins encoded by those genes. Conversely, down-regulation is a process resulting in decreased gene and corresponding protein expression.
A repressor that binds with a co-repressor is termed an aporepressor or inactive repressor. One type of aporepressor is the trp repressor , an important metabolic protein in bacteria. The above mechanism of repression is a type of a feedback mechanism because it only allows transcription to occur if a certain condition is present: the presence ...
The repressor will then bind to the operator, stopping the manufacture of lactase. In genetics, a promoter is a sequence of DNA to which proteins bind to initiate transcription of a single RNA transcript from the DNA downstream of the promoter. The RNA transcript may encode a protein , or can have a function in and of itself, such as tRNA or rRNA.