Which two components activate and form MPF at the Gap2/M-phase transition?

The formation of Maturation Promoting Factor (MPF), which is essential for the transition from Gap 2 (G2) phase to M-phase (mitosis), is primarily driven by the complex of Cyclin B and Cdk1 (Cyclin-dependent kinase 1). In this process, Cyclin B activates Cdk1, leading to the phosphorylation of various target proteins necessary for mitotic entry and progression.

During the G2/M transition, the accumulation of Cyclin B is crucial, as it regulates the activity of Cdk1, allowing the cell to proceed into mitosis. The binding of Cyclin B to Cdk1 induces a conformational change that activates the kinase, enabling it to phosphorylate substrates that trigger the mitotic processes. This is a well-documented aspect of the cell cycle regulation, highlighting the importance of cyclins and Cdks in controlling cell division.

Other components mentioned in the choices, such as histones or general protein kinases, do not specifically relate to the activation of MPF at this critical transition in the cell cycle. Understanding this relationship between Cyclin B and Cdk1 is fundamental in cell biology, particularly regarding how cells control and coordinate their progression through the division cycle.