BRAINCAKETumour Suppressor Genes
Tumour suppressor genes are normal genes that slow down cell division. Their proteins stop the cell cycle when necessary, help repair damaged DNA, and trigger apoptosis (programmed cell death) in cells whose DNA is too damaged to repair. An example is the gene for the protein p53, which stops the cell cycle when DNA is damaged. Others are BRCA1 and BRCA2, whose proteins help repair DNA.
If a tumour suppressor gene is inactivated, its protein is not made or does not work. Cell division is no longer slowed, damaged cells are neither repaired nor destroyed, and cells divide uncontrollably, forming a tumour. A tumour suppressor gene can be inactivated by:
Sign in free to see the rest of this lesson, the R.E.C.I.P.E. recall steps and the quiz
BrainCake is free. Make an account in seconds and pick up where this page stops.
Key terms in this lesson
- mutation
- A random change in the base sequence of DNA (a gene mutation) or in the structure or number of chromosomes (a chromosome mutation).
- apoptosis
- Programmed cell death, a controlled process in which unwanted or damaged cells are broken down into vesicles and removed by phagocytosis without damaging surrounding tissue.
- oncogene
- A mutated or abnormally activated proto-oncogene that is permanently switched on, causing uncontrolled cell division and contributing to tumour formation.
More in Control of Gene Expression
- DNA Methylation
- Histone Acetylation
- Epigenetics and Disease
- Benign and Malignant Tumours
- Oncogenes
- Abnormal Methylation and Cancer
- Oestrogen and Breast Cancer
- Epigenetic Treatments for Cancer
All 18 lessons in Control of Gene Expression · All AQA A-level Biology topics