Which of the following statements is/are correct about the molecule RB?
a)Normal RB is a mutated molecule that causes cancer.
b)If it is phosphorylated, RB blocks cell division.
c)Active RB has the effect of keeping the cell in G1.
d)RB is a molecule whose normal job is to stimulate cell division. (more than one answer can apply)
Answer:
c) is the correct option
Retinoblastoma(Rb) is a tumor suppressor gene. It inhibits cell growth until the cell is ready for division. I t is also essential for G1 to S phase transition. It keeps in the cell in G1 phase by binding to the E2F factor. Once phosphorylated, it becomes inactive and the cell progresses from G1 to S phase. Mutation of Rb may lead to aberant cell division, which may cause cancer.