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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 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 ...
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.
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]
Function. β-Galactosidase is an exoglycosidase which hydrolyzes the β- glycosidic bond formed between a galactose and its organic moiety. It may also cleave fucosides and arabinosides but at a much lower rate. It is an essential enzyme in the human body. Deficiencies in the protein can result in galactosialidosis or Morquio B syndrome.
Expression vectors are the basic tools in biotechnology for the production of proteins. The vector is engineered to contain regulatory sequences that act as enhancer and promoter regions and lead to efficient transcription of the gene carried on the expression vector. [1] The goal of a well-designed expression vector is the efficient production ...
The repressor will then bind to the operator, stopping the manufacture of lactase. In molecular genetics, a repressor is a DNA- or RNA-binding protein that inhibits the expression of one or more genes by binding to the operator or associated silencers. A DNA-binding repressor blocks the attachment of RNA polymerase to the promoter, thus ...