Regulation of Gene expression I: Prokaryotes
What can make an inducible gene turn "on"?
What can make a repressible gene turn "off"?
inducible genes are typically "off" until activated by a specific signal
repressible genes are usually "on" until repressed by a specific molecule
Whats the definition of epigenetic's?
its the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself.
What are the core promotor elements?
(list them)
1. TATA box and the element bound to a protein called
TAT-binding protein.
2. Initiator is bound by the transcription factor.
3. Downstream promotor element is bound by the
transcription factor complex.
4. TFIIB is bound by the TATA box on DNA.
5. Motif 10 element is bound by the TFIID complex
What are the main steps involved in post-transcriptional modification of a pre-mRNA in eukaryotes?
5' capping, Splicing, and Polyadenylation.
What happens to the when there IS and IS NOT excess tryptophan in the environment ?
When there IS excess tryptophan the leader sequence forms a loop structure that will early on terminate transcription by shutting off the operon.
When there IS NOT excess tryptophan the leader sequence forms a anti-terminator structure. It will allow RNA polymerase to continue transcribing the
operon and producing enzymes.
What happens when there is gene imprinting?
only one copy of a specific gene is expressed in an individual, one copy inherited from the mother or the father, while the other copy is silenced
Where is chromatin located?
its located within the nucleus of a eukaryotic cell.
What are microRNAs (miRNAs) and how do they regulate gene expression at the post-transcriptional level?
miRNAs are small non-coding RNA molecules that bind to the 3' untranslated region that will cause degration
What does the Lac Operon do or happen when there is glucose but no lactose in the cell?
What level of transcription would you expect?
When there is glucose but no lactose the lac repressor protein will be bound to the
operator region of the Lac Operon on the DNA; very low transcription
what are places that lncRNAs might come from in relation to a protein coding gene?
IncRNA could come in from a protein coding gene are
Intergenic regions, within the introns of a protein-coding gene, on the antisense strand of a protein-coding gene, or overlapping with the sense strand of a protein-coding gene
what's different between focused and dispersed promoters?
Focused promotor: narrow region where transcription starts
Dispersed promotor: has a wider range of potential start sites spread over a larger area of DNA
How can RNA binding proteins (RBPs) influence post-transcriptional regulation?
once bound they can regulate splicing, stability, localization, and translation of the mRNA molecule
What does the Lac Operon do or happen when there is no glucose but there is lactose in the cell?
What level of transcription is the be expected?
he lac operon will be fully activated, meaning the genes responsible for breaking down lactose will be actively transcribed and expressed
very high level Transcription
What are the jobs of the histone modifications?
Readers: interpret
Writers: add modifications
Erasers: removes modifications
what mechanisms trans regulatory factors use to bind to specific DNA sequences?
cofactors, epigenetic modifications, and cooperative binding of other TFs
How can outside influences factor post-transcriptional regulation?
Environmental cues can trigger changes in the expression of RNA binding proteins.
What does the Lac Operon do or happen when there is glucose and there is lactose in the cell?
What level of transcription is the be expected?
When both glucose and lactose are present in a cell, the Lac Operon will be largely inactive.
transcription will be at a very low level
Which statements about epigenetics and genetics are False?
a. Only genetics is heritable, epigenetics are not heritable changes
b. They are both heritable, but epigenetics is not necessarily permanently
heritable as some marks are lost over time
c. Genetics and epigenetics both refer directly to DNA changes
d. Only genetics refers to DNA information, epigenetics refers to information
about DNA
e. Epigenetics refers to marks that inform about how to express DNA
C and A
how do trans-regulatory factors influence gene expression across different genes in the genome?
by acting as proteins that can bind to specific DNA sequences that are located near multiple genes.
What are some diseases associated with dysregulation of post-transcriptional control?