G2 phase

G2 phase is the third, penultimate phase of the cell cycle, the sequence of events that a cell goes through as it grows and divides. The G2 phase directly precedes the M phase, during which the cell actually splits into two daughter cells.

Overview

The G2 phase follows the S phase, during which the cell's DNA is replicated. During the G2 phase, the cell undergoes the final preparations for mitosis. This includes the synthesis of proteins necessary for mitosis and the checking and repair of the replicated DNA.

Duration

The length of the G2 phase can vary greatly, but on average it lasts about 4 to 5 hours in mammalian cells. In some cells, the G2 phase is omitted entirely, allowing the cell to proceed directly from S phase to mitosis.

Regulation

The progression of the cell cycle, including the transition from G2 phase to mitosis, is tightly regulated by a complex network of proteins. These include cyclins, cyclin-dependent kinases (CDKs), and checkpoint kinases, among others. Disruptions in this regulatory network can lead to uncontrolled cell growth and division, a hallmark of cancer.

See also

• Cell cycle
• Mitosis
• S phase
• Cyclin
• Cyclin-dependent kinase
• Checkpoint kinase

References

• 
  Diagram of the animal cell cycle
• 
  Human karyotype with bands and sub-bands
• 
  G2-M feedback loops
• 
  G2-M Bistability