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BackgroundApoptosisYou're probably wondering what exactly "BAX" is. BAX is a protein in the cell, and is part of the BCL-2 family of proteins. This family of proteins deals with apoptosis. Apoptosis is basically cell suicide - programmed cell death. When the conditions are right, the cells just die, which prevents someone from having uncontrolled cell growth. It has other functions though - for example, your fingers were separated by apoptosis. When a cell goes through apoptosis, it starts by shrinking. The nucleus separates into multiple parts, and they move apart. The cell then breaks apart into small pieces, and is eaten by nearby phagocytes (white blood cells). BAXSo just what does the BCL-2 family of proteins have to do with apoptosis? They control it. The BCL-2 family has two main groups inside of it - BAX, and BCL-2 (which can get quite confusing). These proteins travel through the mitochondria of the cell and depending on the amounts of each, it determines whether to go through apoptosis or not. BAX is pro-apoptosis - that is, it wants the cell to die. BCL -2 the protein, not family, is anti-apoptosis. The mitochondria checks the amount of each gene, and if there is more BAX than BCL-2, then the cell dies. If there is more BCL-2 than BAX, then the cell lives. However, in the case of cancer, the DNA is altered, and the amount of BAX is lowered, and the amount BCL-2 is raised. This causes the cell to live indefinitely. As the cell divides, the growth continues, and the cancer spreads. This can be compared to a city. Check it out! G125ANow, what change are we actually looking for? In the double helix of DNA, there are four possible nucleotides: A, T, C, G. These form pairs, A with T, and C with G. We are looking for the change 'G125A'. This means that, in the 125th position of the promoter (frontal region, the part that intiates the gene) of the BAX gene, there is a G nucleotide. However, if the G125A change is present, that G changes to an A. This can cause some serious problems, as can be imagined. Here are sequencing pictures of this change:
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