Activator (genetics)

Activator (genetics) is a protein that increases gene expression by binding to an enhancer or to a promoter. Activators function by increasing the rate of transcription of a particular gene.

Function

Activators play a crucial role in the regulation of gene expression. They are capable of binding to specific DNA sequences, known as enhancer regions, located upstream or downstream of the gene they regulate. Once bound, they interact with the RNA polymerase and other transcription factors to initiate the process of transcription.

Activators can also bind to promoter regions, which are located at the start of the gene. This binding helps to position the RNA polymerase correctly and enhances its ability to begin transcription.

Types of Activators

There are two main types of activators: general and specific.

General activators are required for all transcription events and are part of the basal transcription machinery. They include proteins such as TFIID, TFIIA, and TFIIB.

Specific activators, on the other hand, are not universally required but instead increase the transcription of specific genes. They bind to specific DNA sequences and interact with the general transcription machinery to enhance transcription.

Role in Disease

Alterations in the function of activators can lead to various diseases. For example, mutations in the gene encoding the activator protein p53 can lead to cancer, as p53 plays a crucial role in controlling cell growth and preventing tumor formation.

See Also

• Repressor (genetics)
• Transcription factor
• Gene expression
• Regulation of gene expression