What r promoters, operators and operon in genetic engg?
An operator is a segment of DNA that a regulatory protein binds to. It is classically defined in the lac operon as a segment between the promoter and the genes of the operon. A repressor or activator can bind to an operator. Promoter is the RNA polymerase binding site. Jacob and Monod proposed the Operon Model of Gene Expression in bacteria. An operon is a series of genes that are transcribed as a single mRNA as well as all of the cis-acting sites that are involved in transcription of the series and/or its regulation. Genes in an operon code for a diffusible gene product which may be a polypeptide or an RNA molecule. There are 2 classes of gene: Structural Genes. Regulator Genes. The sites at which regulator proteins act are also genetic elements. However, their functions are confined to the DNA molecule on which they are located and any genes that are adjacent to the element. They are cis-acting elements.
