Final answer:
Tumor-suppressor genes encode negative regulator proteins such as Rb, p53, and p21 that act as checks to cell-cycle progression, preventing uncontrolled cell division.
Step-by-step explanation:
The proteins encoded by tumor-suppressor genes that test the integrity of the genome and prevent a cell from progressing past a certain point in the cell cycle are called negative regulator proteins. Well-known examples of these proteins include Rb, p53, and p21. These proteins act similarly to brakes in a vehicle, putting up a roadblock to cell-cycle progression until certain conditions are met, ensuring that cells do not undergo uncontrolled division, which could lead to cancer. If mutations occur in these genes, the negative regulatory function may be lost, leading to the potential for cancer development.
Tumor suppressor genes encode proteins that test the integrity of the genome and prevent a cell from progressing past a certain stage in the cell cycle. These proteins are called tumor suppressor proteins. They act as negative regulator proteins, meaning that when activated, they can prevent the cell from undergoing uncontrolled division. Examples of well-known tumor suppressor proteins include retinoblastoma protein (Rb), p53, and p21.