Regulation of Gene Expression

Created March 2020, Offline version here
Video by 'Professor Dave explains', also on his YouTube Channel.

    In Escherichia coli, the trp operon, responsible for tryptophan production, is made up of the , the and 5 trp genes. Normally, the operon is . The trp operon repressor is produced and is present in an state that has affinity for the operator.
    activate(s) the repressor by binding to it and changing its . The active repressor binds to the and turns the operon , by transcription of the trp genes and production of tryptophan. The trp operon is an example of gene expression/regulation, where protein binding dictates whether or not genes will be expressed. Alternatively, gene expression/regulation occurs when proteins are required to interact with in order to activate transcription. These proteins are called transcription factors. Transcription factors have a binding domain with an affinity for a specific . Some transcription factors bind to parts of a gene promoter, such as a . Gene expression can also be controlled through the use of that facilitate gene when tightly bound to genes. When DNA is tightly bound, gene expression is , as cannot access the DNA to transcribe the gene.