| Description |
Transcription factors are proteins which function intracellularly to regulate gene expression. Transcriptional regulation of gene expression is made possible by the DNA binding ability of transcription factors. By binding to specific regions of DNA near the sites at which gene transcription begins, transcription factors facilitate the activation or repression of transcription, thus allowing differential gene expression between cells within any given organism, despite duplicate genetic composition. This differential gene expression then results in divergent protein production among varying cell types, as is characteristic of multicellular organisms. Furthermore, transcription factors regulate normal cell growth and function on a continuing basis throughout the life of the cell. Abnormalities in this regulation cause various cellular irregularities, including cancer. Though transcription factors act primarily to help regulate gene expression, they themselves are also regulated. The regulation of transcription factor function may be accomplished by various methods within the cell, including protein partnership, phosphorylation, and proteolysis. In this thesis, the modulation of Ets-1, a eukaryotic transcription factor, is analyzed. Ets-1 has been implicated in a variety of metabolic regulatory pathways involving cell growth, division, and transformation, and is thus considered to be a proto-oncogene. Herein, the effects of phosphorylation on Ets-1 DNA binding are investigated. Casein Kinase I is used to accomplish the phosphorylation of Ets-1, and gel mobility shift analyses are utilized to determine the effects of such phosphorylationon Ets-1 DNA binding activity. Data indicate substantial inhibition of Ets-1 DNA binding activity upon phosphorylationby Casein Kinase I. Furthermore, the sites of Casein Kinase I phosphorylation are localized by inspection of phosphorylation efficiency data and proteolysis, to the region between amino acid residues N164 and N244 on Ets-1. Intracellularly, Casein Kinase I might easily be utilized as one method of Ets-1 DNA binding modulation. |
