What is the consequence of a mutation in Cdc25 phosphatase?

What is the consequence of a mutation in Cdc25 phosphatase?

• A. It results in premature cell division
• B. It leads to continuous activation of Cdk
• C. It stops cell cycle progression before G1
• D. It causes an arrest at the G2 phase

Answer: (D)

A mutation in Cdc25 phosphatase leads to consequences that disrupt the regulation of the cell cycle, particularly during the G2 phase. Cdc25 is a key regulator that activates cyclin-dependent kinases (Cdks) by removing inhibitory phosphates. This activation is crucial for the transition from G2 to M phase (mitosis). If Cdc25 is mutated, its ability to activate Cdks is impaired, resulting in a failure to progress past the G2 checkpoint. This causes the cell to arrest at the G2 phase, as the necessary signals for entering mitosis are not adequately fulfilled. The cell remains in this phase, preventing it from dividing properly. In contrast, the other options suggest different effects that do not align with the known functions of Cdc25. A mutation would not directly lead to premature cell division or continuous activation of Cdk; rather, it hampers activation, resulting in a cellular checkpoint failure. Similarly, stopping cell cycle progression before G1 (as mentioned in one of the choices) does not accurately describe the consequences of a Cdc25 mutation, as this phosphatase primarily influences events at the G2/M transition.

A mutation in Cdc25 phosphatase leads to consequences that disrupt the regulation of the cell cycle, particularly during the G2 phase. Cdc25 is a key regulator that activates cyclin-dependent kinases (Cdks) by removing inhibitory phosphates. This activation is crucial for the transition from G2 to M phase (mitosis).

If Cdc25 is mutated, its ability to activate Cdks is impaired, resulting in a failure to progress past the G2 checkpoint. This causes the cell to arrest at the G2 phase, as the necessary signals for entering mitosis are not adequately fulfilled. The cell remains in this phase, preventing it from dividing properly.

In contrast, the other options suggest different effects that do not align with the known functions of Cdc25. A mutation would not directly lead to premature cell division or continuous activation of Cdk; rather, it hampers activation, resulting in a cellular checkpoint failure. Similarly, stopping cell cycle progression before G1 (as mentioned in one of the choices) does not accurately describe the consequences of a Cdc25 mutation, as this phosphatase primarily influences events at the G2/M transition.