Gene Expression: Overview of Control

Some eukaryotic gene regulatory proteins work individually, but most act within a complex of proteins. Furthermore, a single gene regulatory protein may participate in multiple types of regulatory complexes. For example, a protein might function in a complex that activates the transcription of one gene and in a complex that represses transcription of another gene.

A gene that must be turned on at different times and in different tissues during development might have gene regulatory proteins clustered at multiple sites along its regulatory region. These complexes can then regulate the expression of the gene in a variety of developmental processes. The rate of RNA synthesis initiation will depend on the combination of regulatory proteins bound to the control regions of the gene. Thus, we can think of the regulatory region of the gene as an information processor, like a computer, that integrates input from all the regulatory proteins present and determines an appropriate level of RNA synthesis.