What is the consequence of a mutation that prevents the degradation of cyclins?

A mutation that prevents the degradation of cyclins disrupts the normal regulation of the cell cycle. Cyclins are proteins that play a crucial role in controlling the progression of the cell cycle by activating cyclin-dependent kinases (CDKs). These cyclins are produced at specific points in the cell cycle, and their levels must be tightly regulated to ensure that each phase of the cycle is completed properly before the cell moves on to the next phase.

When cyclins are not degraded as they should be, their prolonged presence in the cell can lead to continuous activation of CDKs, promoting unchecked progression through the cell cycle. This can result in a situation where the cell divides uncontrollably, potentially leading to conditions such as cancer. The normal "stop" signals that would typically occur due to the degradation of cyclins are bypassed, allowing cells to replicate even when they should not.

Therefore, the consequence of a mutation that prevents cyclin degradation is that cells may undergo unchecked division, which is a key factor in tumorigenesis and the development of cancerous cells.