In: Biology
How is co-expression induced?
Co-expression refers to the expression of multiple genes regulated by the same transcriptional control. These could either be the functionally related genes involved in a common biological process or the ones that are interdependent to elicit a particular response in the cell.
For instance - Operon system - An operon consists of multiple genes that have a coordinated expression in reponse to the regulations imposed by the trancription machinery.
So, how the regulation in this co-expression system is imposed?
This control is elicited in different ways:
1. When product of one gene acts as an inducer for the transcriptional activation of another. For eg- In many pigmented flowers, expression of one gene yields a product that induces another to trancribe so that the pigments are formed.
2. Expression from a single promotor- In operons, cluster of genes involved in a single pathway are regulated by a single promoter. for eg- Lac operon.
3. Epigenetic regulations - Certain epigenetic modifications on gene promotors simultaneously activate genes involved in a particular biological activity. for eg- acetylation by histone acetyltransferases (HATs) is one such modification.