Cytogenetics

Question 1

What is FISH?

Answer 1

Technique for visualising changes in copy number and translocations

Question 2

How does FISH work?

Answer 2

Use of fluorescent oligonucleotide probes that bind to specific target sequence of DNA or RNA

Question 3

How are results obtained?

Answer 3

By fluorescence microscopy

Question 4

What does G-banding require?

Answer 4

Stimulating cells to proliferate and arresting them in metaphase

Question 5

What are oligonucleotide probes?

Answer 5

Formed of an oligonucleotide-ssDNA/ssRNA

Question 6

How do oligonucleotide probes bind?

Answer 6

Will hybridise (bind) to ssDNA

Question 7

Do these probes have a bound fluorophore? and what are they used for?

Answer 7

Yes, used for detection and direct/indirect labelling

Question 8

Explain FISH procedure 2

Answer 8

1. Cells collected
2. Cells fixed and chromosomal DNA denatured by heating
3. In-situ hybridisation of probe
4. Counterstaining w/ DAPI

Question 9

What is chromosomal painting?

Answer 9

Multiple probes binding different regions of the same chromosome paint it

Question 10

How can chromosomal painting be used?

Answer 10

Can be applied to tumours that display multiple chromosomal aberrations

Question 11

Explain BCR-ABL1 fusion gene

Answer 11

t(9;22) that leads to creation of BCR-ABL1 fusion gene on chr22

Question 12

What are translocations?

Answer 12

Exchanges of genetic material between non-homologous chromosomes

Question 13

What does BCR-ABL1 fusion gene cause/drive?

Answer 13

Drives growth of malignant cells
It phosphorylates its target to activate them