Regulation of Gene Expression - Eukaryotes Flashcards
Gene regulation in prokaryotes is at the __________.
In eukaryotes, gene regulation occurs ________.
Level of initiation of transcription
from initiation of transcription to protein degradation
Regulation is up regulated. True or False?
True
Regulation in Eukaryotes is primarily about _______.
turning genes on rather than repression (off)
In eukaryotes gene expression is regulated at
transcription
RNA processing
mRNA turnover
Translation
Post-translational modification
Protein Turnover
Cell Trafficking
Basically every step!
________ is DNA sequences located near the start site for transcription called the _______. General transcription factors bind to ________ to ______.
The proximal promoter is _____ acting while TF’s are _______.
Proximal Promoter, INR (initiator element), the proximal promoter to aid in recruitment of RNA polymerase.
cis-acting factors , trans-acting factors
Cis-acting factors are _____ DNA while trans-acting factors _____ DNA.
in , bind to
Properties of Enhancer/Silencer DNA sequences (___-acting)
cis-acting
- Short DNA sequences as a double strand (8-16 bp)
- Position Independent - can function long distances upstream and downstream of start site of transcription
- Orientation independent- Sequences are palindromic so can function in both 5’-3’/3’-5’ directions equally.
Transcription initiation rates are mediated by _________ that ___________.
sequence-specific DNA binding proteins (trans) that bind to specific DNA sequences near individual promoters.
NO TF will result in ________. __________ of TF is the most effective way to perform functions like recruit RNA polymerase.
No TF will result in NO transcription.
Dimerization
Transcription factors may need to be modified. True or False?
True
Transcription Factors can be modified by :
- Binding of a ligand to inhibit its activity or activate it
- Binding of phosphorous to initiate activity
- Addition of another protein to activate.
Co-activator and co-repressors are required to __________. They ____________ contact DNA.
DO NOT
required to up or down regulate transcription
Rather they bind to transcription factors or another protein.
Changes in _________ to ________ allows to RNA pol ___ to proceed with transcription.
What are some of these changes?
heterochromatin to euchromatin, II
Acetylation and phosphorylation of histone with recruitment of coactivator complexes and loss of Histone 1.
_______ of _______ regulated transcription by ______________ by affecting chromatin _____ and _______ of _______ to ________.
Acetylation of Histones regulates transcription by affecting chromatin compaction and binding of transacting factors to cis-acting elements.
Methylation of ________ in _____ on ___________ results in __________ because it _______.
specific Cytosine residues in CpG islands (C’s and G’s) results in long-term transcription repression because it disrupts binding of transcription machinery.
Epigenetics is ___________ that are not cause by _________.
It is _______.
alterations in gene activity that are not caused by changes in gene sequences
Hereditary
Hypermethylation makes DNA _____________ while hypomethylation.
transcriptionally inactive
transcriptionally active
Some regions of our genes are already methylated. True or false?
True
How is mRNA regulated? (Post-transcriptional)
Alternative splicing
3’ end cleavage
RNA editing
mRNA degradation
How is translation regulated?
Initiation
How are proteins regulated? (Post-transitional)
Modification of proteins, protein targeting, protein degradation
Proteome is _______.
Proteins in our genome
The purpose of alternative splicing is to _________.
Increase protein diversity
80-90% of genes encode pre-mRNA’s that can be spliced
What are the two general modes of translational control?
- Global - Most RNA are are regulated, control is on general initiation factors
- Specific- Subset of mRNAs are regulated. Control is mediated by regulatory protein complexes or long coding RNAs that recognize elements present in 5’ untranslated regions of mRNA.
IRE-BP controls iron homeostasis by regulating ____________which __________.
In iron deficient cells, IRE-BP binds an ____________ and blocks the recruitment of ___________..
In the presence of iron this block is removed __________and IRE-BP adopts a conformation _______.
Regulation occurs at the ______ level.
IRE-BP controls iron homeostasis by regulating translation of ferritin heavy and light chain mRNA which encode the subunits of the iron storage protein.
In iron deficient cells, IRE-BP bind an Iron Response Element and blocks the recruitment of 43S pre-initiation complex to ferritin mRNA.
In the presence of iron this block is removed as an iron-sulphur complex and IRE-BP adopts a conformation unsuitable for IRE binding.
The translational regulation occurs when RNA is unable to align with ribosomes.
miRNA’s
miRNA’s are very small 22 base that regulate translation by targeting a sequence for degradation.
Are post-translational modifications of proteins reversible?
Yes!
Ex. Histone modifications, phosphorylation, ubiquitination, Hydroxylation
What 3 amino acids can be phosphorylated?
Tyrosine, Serine,Threonine
Ubiquitin targets proteins for ______.
Degradation
What are the two main routes for Protein degradation?
Lysosomes
Proteasome complex when signaled by ubiquitination of protein to be degrades
Proteins have ________ life.
half
How does a lysosome not get degrades by its proteolytic enzymes?
Proteins are glycosylated so they have a carbohydrate cover that protect the lysosome and proteins inside.
Aggregates in ________ called ____ can disrupt ________.
Parkinson’s Disease, alpha-synuclein amyloid
disrupt lysosomal function
