Transcription regulation in eukaryotes Flashcards
What determines cell identity
differential gene expression during (embryo)genesis controlled by regulatory sequences and transcription factors
what is the primary point of control for eukaryotic gene expression
initiation of transcription
How is eukaryotic gene expression regulated in response to environmental change
Specific transcription factors control particular sequences which can alter the activity of the promoter even from a distance and downstream
What are the potential points of regulation of gene expression in eukaryotes (8)
remodelling of chromatin
transcriptional regulation (pre-mRNA synthesis)
pre mRNA splicing
mRNA transport
mRNA stability
translational control (ribosome)
post-translational modification
photodegradation
Where do transcriptional activators and reperessors bind
DNA regulatory elements (promoter-proximal or distal sequences)
What determines the levels of transcription in eukaryotes
the efficiency of binding of general transcription factors (promoter strength)
What is the role of activators and repressor proteins in eukaryotes
to enhance or repress basal transcription factors and RNA polymerase at the core promoter
What is an enhancer
clusters of various transcription factor binding sites
orientation independent and can work from a distance
Why can enhancer (or silencer) sequences influence transcription and still be many kB away from the transcription site
DNA bending brings them into contact
What allows bending regions of DNA to be able to make complex shapes
There are no proteins present in the bending region
What is the role of the DNA binding domain
to bring the transcription activation domain into vicinity of the promoter
What is the role of the activation domain
to promote the assembly of the basal transcription machinery
Why do most transcriptional activators have a dimerization region
allows multiple proteins to control the DNA-binding domain
makes them more sequence specific
Explain how eukaryotic transcription factors can work cooperatively
The arrangement of activator binding sites such that two transcription factors can interact allows them to stabilize each other
Can vary in:
helical turn
position of sequence in the genome
DNA bending
What is combinational control
a balance of activators and repressors that regulate the transcription of a gene
