Question

Some people have a very strong apoptotic response because the XKR8 gene is expressed at very high levels and cannot be turned off. Based on the results from below, which gene (A, B, or C) is most likely to be mutated (e.g., non-functional) in these people?

Answer 1

The gene most likely to be mutated, causing a strong apoptotic response due to high levels of XKR8 expression that can't be turned off, is the p53 gene. The p53 protein plays crucial roles in halting the cell cycle, initiating DNA repair, or triggering apoptosis when DNA damage cannot be repaired.

Step-by-step explanation:

The student's question pertains to a strong apoptotic response due to high expression of the XKR8 gene, which cannot be turned off. The gene most likely to be mutated in these individuals is the gene for the p53 protein.

Based on the information provided, p53 is a tumor suppressor protein that plays multiple roles at the G₁ checkpoint of the cell cycle. It is responsible for activating genes that halt the cell cycle for DNA repair, activating DNA repair genes, and initiating apoptosis when DNA damage cannot be repaired. When p53 is mutated, it can cause cells to ignore DNA damage and continue to divide, propagating mutations and leading to cancer. In the context of apoptosis, a functional p53 protein would normally signal cells with irreparable DNA damage to undergo apoptosis. However, a mutated p53 cannot trigger apoptosis, leading to overexpression and lack of regulation of the XKR8 gene leading to a strong apoptotic response.