Question

In eukaryotic cells, there are specific transcription factors (activators) that regulate gene expression. Describe the organization of eukaryotic genes (i.e. promoters/enhancers) and how transcription factors are able to control gene expression and enzyme activity.

a) Throughout the course we discussed the enzyme lactase and how it is differently regulated (and therefore expressed) in different human populations. Describe how this gene is differently expressed in different populations and when this/these change(s) are predicted to have taken place.

b) Differential gene expression is important for cell type specific transcription of genes. Name and describe the different ways that genes can be regulated in eukaryotes, including the role of activators in this process.

Answer 1

RNA polymerase binds to a promoter with help from a set of proteins called general transcription factors. ... Instead, there is a large class of transcription factors that control the expression of specific, individual genes. For instance, a transcription factor might activate only a set of genes needed in certain neurons.

However, unlike prokaryotic cells, the eukaryotic RNA polymerase requires other proteins, or transcription factors, to facilitate transcription initiation. Transcription factors are proteins that bind to the promoter sequence and other regulatory sequences to control the transcription of the target gene.

Transcription factors are proteins possessing domains that bind to the DNA of promoter or enhancer regions of specific genes. They also possess a domain that interacts with RNA polymerase II or other transcription factors and consequently regulates the amount of messenger RNA (mRNA) produced by the gene.