Lac operon transcription in the E. coli bacterium, animation. One of the main ways in which a cell can switch transcription (the first step of gene expression) on and off uses protein repressors to bind to a site (the operator) next to or adjacent to the promoter. When bound this repressor prevents the initiation of transcription. This animation shows the lac operon (a unit of genomic DNA that contains a cluster of genes under the control of a single promoter) being transcribed in the presence of lactose. The repressor (red) is inactivated by lactose (yellow). RNA polymerase can move from its binding site at the promoter along the DNA template and can catalyse the transcription of the genes lacZ, lacY and lacA. These genes code for beta-galactosidase, permease and transacetylase respectively which can then be used by the bacterium to obtain energy from lactose. | |
Licence : | Droits gérés |
Crédit : | Science Photo Library / Biocosmos / Francis Leroy & Mathilde Vanspeybrouck |
Model Release : | Non requis |
Property release : | Non requis |
Durée : | 47 Secondes |
Aspect ratio : | 16/9 |
Restrictions : | - |