Transcription factors

Explain the principles governing interactions between DNA and protein that take place at the promoter or enhancer.

Protein-DNA interactions at promoters or enhancers depend on recognition sequences

Describe the differences between DNA binding domains

using an example protein of each to help you explain their functional differences.

Describe how transcription factors can gain entry to the nucleus to influence transcription.

Transcription factors reveal a nuclear localization signal (NLS) via activation mechanisms such as ligand binding

Explain the effect of multicomponent complexes on DNA binding

including those recruited to the mediator complex.

How do DNA binding proteins move to the nucleus after activation?

They often undergo a conformational change or dissociation from another protein

What mechanisms reveal the NLS of transcription factors?

Ligand binding

What factors govern protein-DNA interactions?

DNA recognition sequence

Why must the protein interface match DNA shape?

Matching allows electrostatic interactions

What are homeobox (HOX) genes and their function?

HOX genes encode proteins that control body patterning during development

How does p53 recognize DNA?

p53 has a DNA binding domain made of two β-sheets that sandwich the DNA and forms multimers through its oligomerization domain

How do zinc finger nuclear hormone receptors bind DNA?

They contain finger-like domains

How does Fos regulate bone via a leucine zipper?

Fos binds DNA only as a dimer through hydrophobic interactions between α-helices

How is Fos activated?

Through kinase signaling cascades leading to phosphorylation

What is the role of Myc in cancer?

Myc is often upregulated

How do multicomponent complexes affect transcription?

Some DNA binding domains fold completely only in the presence of DNA

What is the significance of the mediator complex?

Mediator complexes influence DNA binding protein structure

How can nuclear receptors act as co-activators or co-repressors?

The same DNA binding protein and response element can have different transcription outcomes depending on which mediator proteins are recruited