Genetic+Control+via+Activators+and+Enhancer+Elements

Genetic Control via Activators and Enhancer Elements Gene transcription: - Most gene regulation occurs at the site of transcription - Gene transcription begins at promoter regions - Transcription factors assemble on the promoter region - Basal factors bind to the promoter region along with a TATA binding protein - This captures RNA polymerase which creates the whole transcription initiation complex - These factors are necessary for transcription - However they are only responsible for transcription and not the speed at which it occurs - To effect transcription speed you need to involve an enhancer

Enhancers: - Enhancers are areas of DNA that are responsible for increasing the rates of transcription - Enhancers are often associated with genes that are abundantly expressed - Ex: immunoglobin genes (encode for antibodies), B-hemoglobin gene in humans, and storage genes in soybeans. - Enhancers can be found in regions upstream, downstream, or directly near the gene it enhances - Enhancer regions can be thousands of base pairs away from the gene - This is made possible by binding to activators

Activators: - Activators bind to enhancers connecting them to the promoter region - Activators bind to co-activators which attach themselves to the basal factors in the transcription complex - This creates a loop in the DNA bringing the enhancer closer to the promoter





Importance: The understanding of how this process works is significant in the study of cellular physiology. By understanding how this works it can be used to control expression of genes. By finding out how to signal for these activators it could be controlled and certain cell functions such as creating antibodies could be increased in individuals who have low functioning immune systems.

Papers about Activators and Enhancers:

Marc G Wathelet, Charles H Lin, Bhavin S Parekh, Lucienne V Ronco, Peter M Howley, Tom Maniatis, Virus Infection Induces the Assembly of Coordinately Activated Transcription Factors on the IFN-β Enhancer In Vivo, Molecular Cell, Volume 1, Issue 4, March 1998, Pages 507-518, ISSN 1097-2765, http://dx.doi.org/10.1016/S1097-2765(00)80051-9.

This paper discusses a virus activated enhancer gene that reacts when a cell is infected. The main focus of this paper is on enhancer genes and activators

Weiher H, König M, Gruss P. “Multiple point mutations affecting the simian virus 40 enhancer.”, Science. 1983 Feb 11;219(4585):626-31.

This paper is about how research was done on a certain enhancer gene to find out how the gene is coded. They created point mutations at certain spots on the gene as a way to see what areas are significant for the coding.

Michael Levine1 & Robert Tjian, “Transcription regulation and animal diversity” Nature 424, 147-151 (10 July 2003) | doi:10.1038/nature01763

This paper is a review of how diversity in animal species can be related to the complexity of its gene transcription. The paper using enhancers and activators to show how these regions are more complex than organisms who don’t have them.

References: - [] - [|http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Promoter.html#enhancers] - [] - []