eukaryotic transcription and gene regulation Flashcards
eukaryotic cells have _ classes of RNA polymerase
3
what is the role of RNA polymerase I
transcribes ribosomal RNA in the nucleolus
= components of ribosome
what is the function of RNA polymerase II
transcribes messenger RNA (mRNA) in the nucleoplasm
what is the function of RNA polymerase III
transcribes rRNA, tRNA, and other small RNAs in the nucleoplasm
how many subunits make up all eukaryotic DNA
12 subunits
what does the largest subunit in RNA polymerase II have
carboxy-terminal domain (CTD) consisting of multiple repeats of a heptamer
from what process is mRNA produced
transcription
5’ UTR contains signals for ________ of transcription
initiation
3’ UTR contains translational ________ site
termination
how many phases of transcription are there
3
what are the three phases of transcription
initiation
Elongation
Termination
in transcription, initiation is the first phase, what occurs
chains of 2-9 bases are synthesised and released
in transcription, Elongation is the second phase, what occurs
RNA polymerase synthesises RNA
in transcription, termination is the 3rd and final phase, what occurs
RNA polymerase and RNA and released
what are some requirements for transcription
chromatin must be opened in euchromatin form before RNA polymerase can bind the promoter
basal transcription factors
coactivators
THE STARTPOINT OF RNA POLYMERASE II
RNA polymerase II requires general transcription factors called what to initiate transcription
TFIIX
THE STARTPOINT OF RNA POLYMERASE II
RNA polymerase II requires general transcription factors such as TFIIX to do what
initiate transcription
THE STARTPOINT OF RNA POLYMERASE II
RNA polymerase II promoters usually have a (long/short) sequence
short
THE STARTPOINT OF RNA POLYMERASE II
what is a common component of RNA polymerase II promoters and consists of an A-T rich octamer
TATA box
THE STARTPOINT OF RNA POLYMERASE II
the TATA box is a common component of RNA polymerase II promoters and consists of what
A-T rich octamer
THE STARTPOINT OF RNA POLYMERASE II
The TATA box is a common component of RNA polymerase II promoters and consists of an A-T rich octamer located how far upstream of the start point
~25bp upstream of the start point
why is TATA binding protein important for promoters
its required for each type of RNA polymerase to bind to its promoters
what 2 things are required to melt DNA to allow polymerase movement
TFIIE and TFIIH
TFIIE and TFIIH are required for what after the initiation phase of transcription
they are required to melt DNA to allow polymerase movement
after initiation of transcription, phosphorylation of what is required for promoter clearance and elongation to begin
phosphorylation of C terminal domain (CTD) or RNA polymerase II
after initiation, phosphorylation of the C terminal domain (CTD) or RNA polymerase II are required for what to allow elongation to begin
phosphorylation is required to allow for promoter clearance
transcription is the process of what
process of making an RNA copy of a gene’s DNA sequence
only genes in what form can be transcribed
euchromatin (non-condensed)
what occurs at the transcription initiation site
where the RNA polymerase begins the DNA synthesis
what occurs at the transcription termination site
release the RNA polymerase of the DNA
what is the transcription rate
speed of RNA polymerase activity between the initiation and the termination sites
promoter is a short regulatory DNA sequence upstream of the transcription ______ site sequence
initiation
YYCAYYYYY
Y codes for what
C codes for what
A codes for what
Y - cYtosine, thYmidine
C - Cytosine
A- Adenine
TATA sequence is bound by what
TATA binding protein
what does the TATA sequence allow for
enables to position and build the multi protein RNA polymerase complex upstream of the transcription initiation site
activity of RNA polymerase II (RNA synthesis rate) is fine tuned by what
cyclin dependant kinases
activity of RNA polymerase II (RNA synthesis rate) is fine tuned by what cyclin dependant kinases
CDK9 and CDK12
activity of RNA polymerase II is fine tuned notably by the kinases CDK9 and CDK12, what do they do to the C terminal domain of RNA polymerase II
phosphorylate
in transcription, where is the enhancer site
can be thousands of bases from the start site (upstream)
what do enhancers contain that assist transcription initiation
Bidirectional DNA elements
Enhancers contain bidirectional DNA elements that assist what
Transcription initiation
enhancers form complexes of what that interact directly or indirectly with the promoter
complexes of activators
enhancers form complexes of activators that interact directly or indirectly with what
the promoter
what is a repressor
a protein that inhibits expression of a gene
what protein is responsible for inhibiting the expression of a gene
a repressor
give an example of how a repressor could prevent transcription
it could bind to an enhancer or silencer
give an example of how a repressor could prevent transcription
it could bind to an enhancer or silencer
an enhancer typically activates a promoter of what distance to itself
the closest one - whether upstream or downstream to itself
how do enhancers work
they increase the concentration of activators near the promoter
p53_ is a transcription factor
p53alpha
p53 activates transcription by what
directing strcutural shifts in mediator
ehancers are classically defined as ___ -acting DNA sequences
cis
enhancers are defined as cis-acting DNA sequences that can ______ the transcription of genes
increase
enhancers function independently of orientation at various distances from what
the target promoter
silencers are defined as ___ acting DNA sequences
cis
silencers can be defined as cis-acting DNA sequences that can ____ the transcription of genes
decrease
silencers function independently of orientation and at various distances from what
thir target promoters
the cis acting DNA sequences in ehancers or silencers are specifally bound by transcription factors such as what
p53
the binding specificity and affinity of transcription factor to cis-acting DNA sequences in ehancers/silencers is regulated by what
post translational modifications induced by different cll signals pathways sensing the stimuli or changes in the extracellular and intracellular environment