Question

Classify each of the following into whether it represents a nonmutated proto-oncogene or a tumor suppressor gene. Proto-Oncogenes Tumor Supressor Genes Inhibitors of p53 Apoptosis is restrained Apoptosis is promoted Eventually become inactive Sufficient cyclin Inhibitors of cyclin Eventually become oncogenes Promoters of p53 Cell cycle is restrained Cell cycle occurs normally

Answer 1

Proto oncogenes:

Inhibitors of p53 (when activated, will inhibit p53 which is a tumour suppressor gene);

Apoptosis is restrained (if apoptosis is stopped, damaged cell will continue proliferating and develop tumour);

Sufficient cyclin (drives cell cycle forward forming tumour);

Eventually become oncogenes (which is why they are called proto oncogenes);

Cell cycle occurs normally (promotes tumor formation).

Tumour suppressor gene:

Apoptosis is promoted (on this, the damaged cells are killed so that they don't get to form tumour);

Eventually become inactive (this leads to cancer);

Inhibitors of cyclin (halts the unregulated cell division process);

Promoters of p53 (will stop cell cycle to repair the damaged DNA);

Cell cycle is restrained (slows tumour formation).