Topic 9 Flashcards
What are the layers of control in eukaryotic gene expression?
What does a response element do?
binds a transcription factor
What responses can induce transcription? What is this process called?
Heat, light, steroid or peptide hormones
Signal transduction: transcription factors are the end point of signalling pathways that sense changes in the cellular environment to cause changes in gene expression in the nucleus
Compare transcriptional regulation in bacteria and eukaryotes.
Compare enhancers and promoter-proximal elements.
Enhancers bind special transcription factors and
promoter-proximal elements bind general transcription factors
What is the mediator complex?
a co-activator complex that promotes DNA activation but doesn’t bind DNA
True or false? There are domains found in transcription factors.
True
How do enhancers function?
Enhancers regulate promoter region through loops in chromatin
enhancers function by forming enhanceosomes, which are large protein complex that acts synergistically to activate transcription.
Formed by binding of multiple regulatory proteins to the multiple binding sites in an enhancer.
Enhanceosomes recruit chromatin modifiers that locally unwrap promoter regions.
What several factors influences mRNA stability?
- the polyA tail
- the sequence of the 3’UTR
- chemical factors (e.g. hormones)
- small interfering RNAs (siRNAs) or microRNAs (miRNAs)
What is the role of RNA interference (RNAi)?
Short noncoding RNA regulate gene expression by binding with mature mRNA to make dsRNA.
RNAi specifically reduces the expression of target genes by removing processed mRNAs to prevent translation.
What is the function of DICER for RNAi?
Detects dsRNA and processes it
dsRNA comes from two sources:
exogenous and endogenous
What is meant by the statement sdRNA is bound by dicer?
Dicer is a nuclease that cleaves dsRNA into smaller RNAs called small interfering RNAs (siRNAs) derived from long dsRNAs or mature micro RNAs (miRNAs) if produced from miRNAs.
