Yeast As A Model For Disease

Question 1

What are the 2 types of yeast called

Answer 1

Sachramyces cerevisiae (budding)

Schizosachromyces pombe (fission)

Question 2

Name the main reasons for yeast being studied for human disease

Answer 2

The whole genome is sequenced

Knockout genes are possible to produce mutants

Easy to grow

Same cell cycle

Can be haploid and diploid

Question 3

What do yeast have in common with humans

Answer 3

They have the same cell cycle 4 phases G1,2 S and M phase

Question 4

How many genes does pombe fission yeast have associated with cancer

Answer 4

141 genes

Question 5

How is yeast cyclin dependant kinase different to ours

Answer 5

They only have one type , humans have many of both kinase and cyclins to control cell cycle

Question 6

Why does the fact yeast are unicellular matter for diseases

Answer 6

Diseases start at cellular level eg at cell cycle

Question 7

What is the biggest factor of cancer in the cell cycle

Answer 7

Mutations to the checkpoints

Increased growth factor signals due to protooncogenes mutations can cause checkpoints to proceed (encode cyclins)

Or no tumour suppressors eg p53 so no cell death

Or atm genes for dna damage signals

Question 8

What are the 2 genes that cerevisea have homologous genes to for cancer

Answer 8

MSH2 - dna repair gene

ATM - radiation sensitivity

Question 9

What cancer in humans is mutation to MSH repair gene related to

Answer 9

Colon cancer hereditary

Question 10

How did they find MSH2 role in cancer using yeast

Answer 10

Yeast have a homologous gene which was found to control dna repair

Question 11

What is the homologous genes in yeast for the ATM radiation sensitivity gene in humans

Answer 11

MEC1, TEL 1

Question 12

What was MEC 1 and TEL 1 in yeast found to do

Answer 12

It was involved in encoding kinases involved in response to dna damage
They would activate p53 to inactivate Cyclin dependant kinase stopping cell division

Mutation caused no response and cell cycle continued
= cancer

Question 13

How was the study of genes such as MSH2 and ATM (mec and tel) used for anti cancer targeting

Answer 13

They would find genes to target which would then kill cancer cells if the mutation was present

Only if mutation is present to prevent healthy cell death

Question 14

Name some other diseases which were studied using cerevisiae

Answer 14

Werner and Bloom’s syndrome - causing premature age related defects

The homologous gene to Werner and Bloom’s syndrome found in yeast also called age related cell defects