Lecture 1 - Exam 3 Flashcards
Chromatin within the nucleus is organized into…?
Looped domains formed by the interaction of the CTCF transcription factor and Cohesin.
Enhancers are restricted to…?
Interacting with promoters in the same domain.
CTFC = ?
CCCTC-Binding factor
The CREs are the same in every cell, so what’s different?
CREs are modular.
What can transcription factors do once they are bound to CREs?
Once bound to CREs, TFs are able to enhance and/or repress the ability of RNA polymerase II to initiate transcription.
Combinatorial gene expression… is it important? What is it?
SO IMPORTANT!
Allows multiple genes to be expressed. For example, Gene A being expressed in brain and limb.
The transcription factors bring the _________ to the enhancer. Depending on where the gene will be expressed, those specific TFs will be expressed and that is what determines where the gene will be expressed (slide 6).
Mediator.
While there is modularity between different CREs that are also __________ units WITHIN each CRE.
co-dependent
While there is modularity between different CREs, there are also co-dependent units within each CRE. In other words, not only is it the combination of CREs that will activate/repress a gene’s transcription…. It is also?
It is also the combination of TFs within a CRE that will influence whether the CRE promotes or silences transcription.
Development is controlled by?
Differential gene expression.
Every somatic cell contains?
The complete genome.
Unused genes retain the potential for?
Expression.
How much of the genome is expressed in each cell?
Small percentage.
What does the Situ Hybridization show us?
This shows us when and where mRNA is transcribed in the cell. But, this technique does not tell us what CREs and TFs turn these genes on.
What is the key technique used in gene expression?
Reporter gene assay. This technique was able to tell us whether or not NRSE sequence is a silencer or an activator.
Transcriptional activators and repressors are associated with ____________ and ___________, which have ______ and _______ activities, respectively.
Coactivators ; Corepressors ; HAT ; HDAC
REMEMBER: Histone acetylation is characteristic of?
Actively transcribed chromatin.
What may be attached to coactivators like HATs?
Pioneer factors.
Wherever the TF can bind on the genome, will do what?
It will open up the chromatin and if the correct TFs are around in a cell, they can bind any uncovered TT binding sites in any CREs surrounding a gene.
From differentiated fibroblast to induced pluripotent stem cell with four transcription factors. What are these transcription factors called?
Yamanaka factors - Oct3/4, c-Myc, Sox2, Klf4.
Note: These are master control pioneer transcription factors.
The Yamanaka factors are virally inserted into differentiated fibroblasts, what will these cells dedifferentiated into?
These cells will dedifferentiate into induced pluripotent stem cells (iPSCs).
Like embryonic stem cells, iPSCs can give rise to?
All three germ layers (mesoderm, ectoderm, and endoderm).
Note: Mesoderm includes red blood cells, Ectoderm includes neurons, and Endoderm lineages include pancreatic endocrine cells.
What is Antennapedia?
A Hox family master control gene that controls the formation of legs during development.
Translation is what stage of gene expression?
The final stage.
