Gene Regulation in Eukaryotes

These flashcards cover key concepts related to gene regulation in eukaryotes, focusing on transcription factors, chromatin structure, and gene expression processes.

What is constitutive expression in gene regulation?

Gene expression that occurs continuously and at a constant rate.

What type of genes are not regulated?

Housekeeping genes.

What is the role of operons?

They coordinate gene expression in bacteria.

At what stage does most gene regulation take place?

Transcription initiation.

Name two ways gene regulation can occur post-transcriptionally.

mRNA stability and translation initiation.

What is a major difference in gene regulation between bacteria and eukaryotes?

Eukaryotic gene regulation is more complex due to histones and chromatin structure.

What do specific transcription factors do?

They regulate transcription initiation.

What are the two types of specific transcription factors?

Activators and repressors.

What role do enhancers play in transcription regulation?

They help enhance the binding of transcription factors to the promoter.

What is the function of regulatory promoters?

Located upstream of the core promoter, they help regulate transcription.

What happens during mRNA processing that is unique to eukaryotes?

It involves the 5’ cap addition and poly(A) tail addition.

How is transcription termination different in bacteria and eukaryotes?

Different mechanisms exist for transcription termination.

What binds to the Shine-Dalgarno sequence in bacteria?

The ribosome.

What stabilizes the basal transcription apparatus?

Interactions between activators and general transcription factors.

What happens when galactose is absent in galactose metabolism?

Gal80 binds Gal4, blocking transcription activation.

What does Gal3 do in the presence of galactose?

It binds to Gal80, allowing Gal4 to activate transcription.

What are chromatin remodeling complexes?

Proteins that alter chromatin structure to regulate gene expression.

What effect does less compact chromatin have?

It increases transcription.

What are the three processes that regulate transcription initiation through chromatin?

Chromatin remodeling, histone modification, and DNA methylation.

How do histone modifications affect gene expression?

They recruit proteins that can either activate or repress transcription.

What is DNase I's role in studying chromatin structure?

It cleaves DNA when it is not bound by proteins, helping assess chromatin packaging.

What is the first step in a DNase I hypersensitivity assay?

Isolate chromatin (DNA + bound proteins).

What does a lack of nucleosomes indicate?

That the gene is likely transcriptionally active.

What is the significance of the Gal4 transcription factor?

It is an activator involved in regulating galactose metabolism in yeast.

What do transcription factors interact with at the promoter?

General transcription factors.

What does the term 'distal regulatory elements' refer to?

Regulatory elements located further from the promoter.

How are gene expressions usually coordinated?

Through the interaction of multiple genes.

What is a common mechanism of action for repressors?

Preventing activators from interacting with the basal transcription apparatus.

What are the roles of enhancers and silencer elements?

Enhancers promote and silencers inhibit transcription.

What is the general function of the 5’ UTR and 3’ UTR in genes?

They are important for the regulation of translation and stability of mRNA.

How does chromatin structure affect transcription initiation?

It influences the accessibility of the promoter to RNA polymerase.

What is the relationship between chromatin structure and transcription?

Compacted chromatin represses transcription, while open chromatin promotes it.

What occurs during the binding of Gal4 to UAS?

It recruits general transcription factors to activate transcription.

What specifically modifies the histone tails to affect transcription?

Acetyl groups, methyl groups, and phosphate groups.

What does DNA methylation typically result in?

Repression of transcription.

What is the role of transcriptional activators?

They enhance the transcription of specific genes.

What condition leads to the destabilization of the basal transcription apparatus?

When Gal80 binds Gal4 in the absence of galactose.

What is unique about eukaryotic gene regulation compared to prokaryotes?

It involves chromatin structure and more complex regulatory mechanisms.

What do transcription factors primarily interact with?

Specific DNA sequences recognized by each factor.

Why is the regulatory element UAS important in yeast?

It enhances transcription of genes involved in galactose metabolism.

What happens during gene regulation when transcription factors bind to DNA?

They can either enhance or suppress transcription of target genes.

What method is used to map DNA fragments to the genome?

Next generation sequencing techniques.