BGM1004/L20 Yeast as a Model

Question 1

Name the 2 common yeast used as a model to understand human genetic disease.

Answer 1

Saccharomyces cerevisiae
Schizosaccharomyces pombe

Question 2

Why is yeast a good model for genetic disease?

Answer 2

Conserved fundamental processes such as cell division cycle

Question 3

Give 3 advantages of yeast as human genetic disease models.

Answer 3

Genome sequences available
Easy to delete genes
Unicellular and grow in defined media
Haploid and diploid cell cycle
Well conserved fundamental processes

Question 4

Approximately how many years of evolution separate S. cerevisiae and S. pombe?

Answer 4

600 million years

Question 5

Describe the products of Saccharomyces cerevisiae mitosis.

Answer 5

Resultant cells are different sizes

Question 6

Describe the cell growth in Schizosaccharomyces pombe.

Answer 6

Cell elongation - ‘budding’
Cells do not widen

Question 7

Name the cyclin-dependent kinase (CDK) that interacts with phase-specific cyclins in Saccharomyces cerevisiae.

Answer 7

Cdc28

Question 8

In G1 of S. cerevisiae, what cyclins does Cdc28 interact with?

Answer 8

Cln1
Cln2
Cln3

Question 9

In S phase of S. cerevisiae, what cyclins does Cdc28 interact with?

Answer 9

Clb5
Clb6

Question 10

In G2 of S. cerevisiae, what cyclins does Cdc28 interact with?

Answer 10

Clb1
Clb2
Clb3
Clb4

Question 11

In G1 of the mammalian cell cycle, what CDKs and cyclins interact?

Answer 11

CDK4&6
Cyclin D

Question 12

In S phase of mammalian cells, what CDKs and cyclins interact?

Answer 12

CDK2
Cyclin A&E

Question 13

In G2 of the mammalian cell cycle, what CDKs and cyclins interact?

Answer 13

CDK1
Cyclin A

Question 14

In M phase of mammalian cells, what CDKs and cyclins interact?

Answer 14

CDK1
Cyclin B

Question 15

Describe the order of peaks in cyclin levels throughout mitosis.

Answer 15

E, A, B
Cyclin D increases and stays high throughout before dropping towards M phase

Question 16

What checkpoint of mitosis is the start point in yeast?

Answer 16

G1 phase checkpoint

Question 17

What occurs at the G1 phase checkpoint in yeast?

Answer 17

Nutrients
Cell size control

Question 18

What occurs at the G2M checkpoint in yeast?

Answer 18

Ensures DNA replication is complete
Cell big enough
Good environment

Question 19

What occurs at the M phase checkpoint in yeast?

Answer 19

Ensures correct spindle attachment
Triggers chromatid separation

Question 20

What occurs at the G0 phase checkpoint in yeast?

Answer 20

Cells exit the cell cycle

Question 21

What is the most common cause of cancer?

Answer 21

Mutation of cell cycle checkpoint mechanisms

Question 22

What is the most common checkpoint in which mutations occur?

Answer 22

G1

Question 23

What is the DNA repair gene in S. cerevisiae?

Answer 23

MSH2

Question 24

What is the cell cycle checkpoint gene in humans?

Answer 24

ATM

Question 25

What are human mutations in the MSH2 gene associated with?

Answer 25

Hereditary non-polyposis colon cancer

Question 26

What are human mutations in the ATM gene associated with?

Answer 26

Ataxia telangiectasia
Increased sensitivity to ionising radiation

Question 27

In S. cerevisiae, which 2 genes have high homology to ATM in humans?

Answer 27

MEC1 and TEL1

Question 28

What does ATM, MEC1 and TEL1 encode?

Answer 28

Protein kinase/protein involved in cell cycle checkpoint control in response to DNA damage

Question 29

Approximately what percentage of genes in S. pombe include ‘disease-associated’ proteins?

Answer 29

6-7%

Question 30

What are mutations in the WRN/BLM genes associated with?

Answer 30

Werner and Blooms syndrome
Premature age-related defects in patients

Question 31

What is the gene high very high homology to human WRN/BLM genes in yeast?

Answer 31

SGS1

Question 32

What are mutations in the NF1 gene associated with?

Answer 32

Neurofibromatosis type 1
Single-gene disorder with high incidence of complex cognitive symptoms

Question 33

What 2 genes in S. cerevisiae have high homology to human NF1?

Answer 33

IRA1 & IRA2