Midterm 1 - Notes 3 (Part 1) Flashcards
What are four examples of transcription factors?
- Tbx4
- Tbx5
- Pitx1
- Pitx2
When are homeotic genes express?
Expressed early during hind limb development
What are homeotic genes?
They are developmental master regulators for development that are involved with hind limb development
Tbx4 (3)
- Required for proper leg development
- Involved in the regulation of embryonic development processes
- Known for its role in development of the hind limb and the formation of the umbilicus
Where is Tbx5 expressed
Is strongly expressed in the wings
- very specific to forearms
What is Pitx1 involved with?
Organ development of the left and right asymmetry
What is Pitx2 involved with?
The development if the eyes, tooth and abdominal organs
Who is a transcription regulator of prolactin?
Pitx2
Transcription factor
Is a protein that controls the rate of transcription of genetic information from DNA to mRNA by binding to a specific DNA sequence
What does transcription initiation require?
Requires the presence of transcription activator proteins
- they bind to specific short sequences of DNA
Enhancer
Transcription factor binding site on target genes
What are the 2 modular structure protein domains?
- Protein protein interaction
2. DNA binding domain
What happens in the protein protein interaction domain?
Proteins act with other proteins that initiate/ regulate other target genes
- it acts as transcription activator
What happens in the DNA binding domain?
Binds to and recognizes the cis element of the target gene thats up/ down stream of the target stream
What does the binding allow in the DNA binding domain?
The binding allows the protein protein interaction domain to get involved and initiates the transcription of the target gene
What are the 2 cis elements?
- Enhancer
2. TATA box
TATA box
Is a DNA sequence that indicates where a genetic sequence can be read and decoded
- type of promoter for transcription
What are the 3 trans regulatory proteins?
- Transcription factors
- Co-regulators
- Histone modification
Co-regulators
Such as co-activators and co-repressors that help the increase or decrease of transcription factors fro gene expression
Histone modification
Is a covalent post-translational modification (PTM) to histone proteins which includes methylation, phosphorylation, acetylation, ubiquitylation and sumoylation
How do histone modification impact gene expression?
By altering chromatin structure
What do gene regulatory proteins form?
Multi protein complexes
What defines target gene expression levels?
A combination of cis-elements and transcription factors
Which transcription factor has a highly conserved homeodomain?
Pitx1
What will a highly conserved homeodomain indicate?
This will indicate to which cis-regulatory element which enhancer region these proteins will bind to or be able to bind to
Without the high LOD score, would they have continued their research? Why or why not?
No, because there could have been many other proteins that could have caused this effect
In situ hybridization
Is a type of hybridization that uses a labeled complementary DNA, RNA or modified nucleic acids strand (ie. probe) to localize a specific DNA or RNA sequence in a portion or section of tissue
Where was the Pitx1 expressed and where was it not expressed?
- It was expressed in the pelvic region in marine form (they developed a spine)
- It was not expressed in the benthic form (will not develop a spine)
- -> this is what we expected because the benthic fish didnt normally develop a spine
What does the Pitx1 gene effect other than high limb development? (2)
- Thymus
2. Neuromast cells
