Midterm 1 - Notes 3 (Part 1)

Question 1

What are four examples of transcription factors?

Answer 1

1. Tbx4
2. Tbx5
3. Pitx1
4. Pitx2

Question 2

When are homeotic genes express?

Answer 2

Expressed early during hind limb development

Question 3

What are homeotic genes?

Answer 3

They are developmental master regulators for development that are involved with hind limb development

Question 4

Tbx4 (3)

Answer 4

1. Required for proper leg development
2. Involved in the regulation of embryonic development processes
3. Known for its role in development of the hind limb and the formation of the umbilicus

Question 5

Where is Tbx5 expressed

Answer 5

Is strongly expressed in the wings

- very specific to forearms

Question 6

What is Pitx1 involved with?

Answer 6

Organ development of the left and right asymmetry

Question 7

What is Pitx2 involved with?

Answer 7

The development if the eyes, tooth and abdominal organs

Question 8

Who is a transcription regulator of prolactin?

Answer 8

Pitx2

Question 9

Transcription factor

Answer 9

Is a protein that controls the rate of transcription of genetic information from DNA to mRNA by binding to a specific DNA sequence

Question 10

What does transcription initiation require?

Answer 10

Requires the presence of transcription activator proteins

- they bind to specific short sequences of DNA

Question 11

Enhancer

Answer 11

Transcription factor binding site on target genes

Question 12

What are the 2 modular structure protein domains?

Answer 12

1. Protein protein interaction

2. DNA binding domain

Question 13

What happens in the protein protein interaction domain?

Answer 13

Proteins act with other proteins that initiate/ regulate other target genes
- it acts as transcription activator

Question 14

What happens in the DNA binding domain?

Answer 14

Binds to and recognizes the cis element of the target gene thats up/ down stream of the target stream

Question 15

What does the binding allow in the DNA binding domain?

Answer 15

The binding allows the protein protein interaction domain to get involved and initiates the transcription of the target gene

Question 16

What are the 2 cis elements?

Answer 16

1. Enhancer

2. TATA box

Question 17

TATA box

Answer 17

Is a DNA sequence that indicates where a genetic sequence can be read and decoded
- type of promoter for transcription

Question 18

What are the 3 trans regulatory proteins?

Answer 18

1. Transcription factors
2. Co-regulators
3. Histone modification

Question 19

Co-regulators

Answer 19

Such as co-activators and co-repressors that help the increase or decrease of transcription factors fro gene expression

Question 20

Histone modification

Answer 20

Is a covalent post-translational modification (PTM) to histone proteins which includes methylation, phosphorylation, acetylation, ubiquitylation and sumoylation

Question 21

How do histone modification impact gene expression?

Answer 21

By altering chromatin structure

Question 22

What do gene regulatory proteins form?

Answer 22

Multi protein complexes

Question 23

What defines target gene expression levels?

Answer 23

A combination of cis-elements and transcription factors

Question 24

Which transcription factor has a highly conserved homeodomain?

Answer 24

Pitx1

Question 25

What will a highly conserved homeodomain indicate?

Answer 25

This will indicate to which cis-regulatory element which enhancer region these proteins will bind to or be able to bind to

Question 26

Without the high LOD score, would they have continued their research? Why or why not?

Answer 26

No, because there could have been many other proteins that could have caused this effect

Question 27

In situ hybridization

Answer 27

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

Question 28

Where was the Pitx1 expressed and where was it not expressed?

Answer 28

• 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

Question 29

What does the Pitx1 gene effect other than high limb development? (2)

Answer 29

1. Thymus

2. Neuromast cells