_____ can selectively enhance the growth and proliferation of mutated cells.
1 An oncogene may cause a cell to secrete growth factors even though it does not normally do so. 2  It will thereby induce its own uncontrolled proliferation (autocrine loop), and proliferation of neighboring cells. 3  It may also cause production of growth hormones in other parts of the body. Human cells were imaged on a confocal microscope with Akt1 labeled green, yleaf labeled pink, and the cell nuclei labeled blue. One set of cells had the healthy version of Akt1 (WT, top) and the other cancer-causing version (E17K, bottom). The yleaf targeted peptide only finds its target and remains in the cancerous cell line. The zoomed view shows the green Akt1 colocalized with the pink peptide in the cytoplasm of the cancerous cells. These two proteins differ by a single amino acid which can mutate from a negatively charged glutamic acid (green) to a positively charged lysine (red). One of them is essential for every healthy cell, and the other causes cancer. signal transduction. - process of transmitting growth signals from external envt to the cell nucelus, initiating program of gene expression that propels cell out of G0 and back into cell cycle-cancer cells = defects in signal transducation pathways. An oncogene is a gene that has the potential to cause cancer. In tumor cells, they are often mutated or expressed at high levels. Most normal cells will undergo a programmed form of rapid cell death (apoptosis) when critical functions are altered. Activated oncogenes can cause those cells designated for apoptosis to survive and proliferate instead. Most oncogenes require an additional step, such as mutations in another gene, or environmental factors, such as viral infection, to cause cancer. clonal. - all cancer cells in primary/secondary tumors are originated from common ancestral cell that accumulated specific mutations-evidence: 1. BURKITT'S LYMPHOMA = all lymphoma cells in each patient contain identical translocation breakpoints-all have same genetic problems 2. - development of malignant tumor-each step appears to be result of one or more generic alterations that progressively release the cell from the normal conditions on cell growth and proliferation-cells end up escaping regulation of cell cycle and differentiation. Share this: A mutation that switches the seventeenth amino acid in the Akt1 protein from a negatively charged glutamic acid to a positively charged lysine (shown in red) is sufficient to cause cancer. - demonstrates that cancer develops from accumulation of several mutagenic events in a single cell-cancer is a MULTISTEP PROCESS REQUIRING MULTIPLE MUTATIONS-incidence of most cancers rises exponentially with age-as we age, we accumulate more and more mutations-cancer gets more aggressive with time. Next, a second PCC screening process was used to find amino acid chains that could be used to extend the yleaf molecule, giving it the ability to grip multiple naturally occurring features of the Akt1 molecule, rather than requiring a click handle to be artificially inserted.
Oncogene