Lec 5 Flashcards
Where are the cis- and trans- elements located?
The cis-elements are on the DNA
The trans-elements are on the opposite
trans-acting elements: transcription factors (proteins that will bind to DNA)
What is one of the mRNA degradation pathways
mRNA degradation has 4 different pathways
- nonsense-mediated mRNA decay (NMD)
What pathway does protein degradation undergo?
protein degration
ubiquitin proteasome pathway
During the exonuclease decay pathway, mRNA degradation starts at the ________ of mRNA
During the exonuclease decay pathway, mRNA degradation starts at the 3’ end of mRNA
Is mRNA degradation a simple process
no, mRNA degradation is a complex of many diff proteins
why is RNA sometimes degraded?
There is a splice mutation so there is a partial intron in the mRNA seq that hasn’t been spliced out correctly
therefore this surveilance system (mRNA degradation pathway) picks up and degrades mRNA and not made into protein.
What is the purpose of methylated guanosine cap on mRNA
Methylated guanosine cap on the 5’ end for stability
Decsribe the exonuclease decay pathway
In the exonuclease decay pathway
We have a mature mRNA transcript with a methylated guanosine cap on the 5’ end for stability and a poly(A) tail on the 3’ end.
Proteins come in to the 3’ end of the mRNA at the poly(A) tail.
Poly(A) tail is for stability of the mRNA and helps for the export of the mRNA into the cytoplasm.
A range of protein bind to remove the poly(A) tail. Once the tail has been removed, another set of proteins come in to remove the 5’ guanosine cap.
Then, 2 enzymes start degraded the mRNA from each side.
template strand direction
3’=>5’
If the promoter is on the left of the coding region is it located upstream/downstream of the coding region
upstream<=======>downstream
promoter = upstream of coding region
define cds
coding sequence
Where can regulatory elements be located?
give an example of a regulatory element
upstream of coding region and/or promoter
enhancer
Define an enhancer
A regulatory element where the transcription factor can bind to and increase the transcription levels
Define an enhancer
A short DNA seq where the transcription factor can bind to and increase the transcription levels
Define transcription factors
They are proteins that bind to the enhancer (region of DNA) to promote transcription levels of a particular gene
Define repressors
Repressors are proteins that bind to the enhancer (DNA seq) and lower the transcription rate
aka transcription factor
Define silencers
If a repressor bind to a silencer that can inhibit gene expression
A silencer is a DNA seq that can be bound to transcription regulatory factors
Define insulator
Another regulatory factor that can be located upstream or downstream of the coding region is an insulator.
Insulator regulates the expression of an enhancer.
Therefore, the insulator can block the enhancer
When RNA is transcribe from DNA it can be transcribed as:
When RNA is transcribe from DNA it can be transcribed as: lncDNA rRNA tRNA miRNA mRNA
T/F
the combination of gene that are expressed or repressed determine cellular form and function
T
Cell-intrinsic regulation can be divided into __ groups what are they?
Cell-intrinsic regulation can be divided into 2 groups
- environmental cures (outside the cell)
2.
Define environmental cues
They are cell-extrinsic regulation factors
- small molecules, secreted proteins, temp and oxygen act as input materials which affect a receptor protein on the cell membrane. Once the membrane receptors have bound to the receptor proteins, they will start a cascade of protein reactions where a lot of proteins are activated by being phosphorylated by protein kinase
e. g the activation of a transcription factor will occur which then binds somewhere depending on the consensus sequences in the DNA
There is a specific sequence on the DNA that the transcription factor binds to.
How do we activate a DNA to be transcribed into an RNA transcript
1 way= environmental signals that come from outside the cell
T/F
Within the organism, cells communicate with each other by sending and receiving secreted proteins (growth factors, morphogens (pattern formation) cytokines, or signalling molecules)
T
