BGM1004/L20 Yeast as a Model Flashcards
Name the 2 common yeast used as a model to understand human genetic disease.
Saccharomyces cerevisiae
Schizosaccharomyces pombe
Why is yeast a good model for genetic disease?
Conserved fundamental processes such as cell division cycle
Give 3 advantages of yeast as human genetic disease models.
Genome sequences available
Easy to delete genes
Unicellular and grow in defined media
Haploid and diploid cell cycle
Well conserved fundamental processes
Approximately how many years of evolution separate S. cerevisiae and S. pombe?
600 million years
Describe the products of Saccharomyces cerevisiae mitosis.
Resultant cells are different sizes
Describe the cell growth in Schizosaccharomyces pombe.
Cell elongation - ‘budding’
Cells do not widen
Name the cyclin-dependent kinase (CDK) that interacts with phase-specific cyclins in Saccharomyces cerevisiae.
Cdc28
In G1 of S. cerevisiae, what cyclins does Cdc28 interact with?
Cln1
Cln2
Cln3
In S phase of S. cerevisiae, what cyclins does Cdc28 interact with?
Clb5
Clb6
In G2 of S. cerevisiae, what cyclins does Cdc28 interact with?
Clb1
Clb2
Clb3
Clb4
In G1 of the mammalian cell cycle, what CDKs and cyclins interact?
CDK4&6
Cyclin D
In S phase of mammalian cells, what CDKs and cyclins interact?
CDK2
Cyclin A&E
In G2 of the mammalian cell cycle, what CDKs and cyclins interact?
CDK1
Cyclin A
In M phase of mammalian cells, what CDKs and cyclins interact?
CDK1
Cyclin B
Describe the order of peaks in cyclin levels throughout mitosis.
E, A, B
Cyclin D increases and stays high throughout before dropping towards M phase
What checkpoint of mitosis is the start point in yeast?
G1 phase checkpoint
What occurs at the G1 phase checkpoint in yeast?
Nutrients
Cell size control
What occurs at the G2M checkpoint in yeast?
Ensures DNA replication is complete
Cell big enough
Good environment
What occurs at the M phase checkpoint in yeast?
Ensures correct spindle attachment
Triggers chromatid separation
What occurs at the G0 phase checkpoint in yeast?
Cells exit the cell cycle
What is the most common cause of cancer?
Mutation of cell cycle checkpoint mechanisms
What is the most common checkpoint in which mutations occur?
G1
What is the DNA repair gene in S. cerevisiae?
MSH2
What is the cell cycle checkpoint gene in humans?
ATM
What are human mutations in the MSH2 gene associated with?
Hereditary non-polyposis colon cancer
What are human mutations in the ATM gene associated with?
Ataxia telangiectasia
Increased sensitivity to ionising radiation
In S. cerevisiae, which 2 genes have high homology to ATM in humans?
MEC1 and TEL1
What does ATM, MEC1 and TEL1 encode?
Protein kinase/protein involved in cell cycle checkpoint control in response to DNA damage
Approximately what percentage of genes in S. pombe include ‘disease-associated’ proteins?
6-7%
What are mutations in the WRN/BLM genes associated with?
Werner and Blooms syndrome
Premature age-related defects in patients
What is the gene high very high homology to human WRN/BLM genes in yeast?
SGS1
What are mutations in the NF1 gene associated with?
Neurofibromatosis type 1
Single-gene disorder with high incidence of complex cognitive symptoms
What 2 genes in S. cerevisiae have high homology to human NF1?
IRA1 & IRA2
