Question

There is a gene in eukaryotes under the control of a transcriptional activator that ultimately regulates chromatin structure. This transcription factor requires dimerization to function. Given your understanding of how transcription factors work, list four different mutations that could disrupt the regulation of this gene and the functional consequences of these individ ual mutations. Consider both cis- and trans- acting elements and different protein domains.

Answer 1

Several different mutations can render Transcription Activators unable to promote transcription of it's target gene:

1. Mutation that prevents Transcription Factor Dimerisation: In the given example, because the Transcription Factor requires dimerisation to function. A mutation that disrupts dimer formation will prevent the Transcription Factor from activating gene transcription.
2. Mutation that prevents Transcription Factor from binding to Chromatin Remodeling Proteins: Since this transcription activator results in Chromatin remodeling, a mutation in the domain that binds to and recruits chromatin remodeling proteins will prevent the transcription factor from being able to promote chromatin remodeling.
3. Mutation that prevents Transcription Factor from binding DNA: A mutation that abrogates either the ability or the specificity of Transcription Activator to bind to DNA will prevent the activator to effectively promote transcription of the target gene.
4. Mutation that prevents binding of co-activator: Many activators promote transcription from a locus in the presence of a co-activator. A mutation that prevents the binding of the co-activator to the activator will prevent expression of the target gene.