The 11th cycle contains a long
G2 phase compared to the previous cycles, and the cells migrate toward the midline.
As the expression of cyclin A begins during the late Gl-early S phase, cyclin B expression occurs during the late S phase and peaks through the
G2 phase (30), (31).
Finkel and colleagues previously discovered that Vif causes HIV-infected cells to stop growing at one phase of the cell cycle, the
G2 phase. The study team has now found that Vif also acts at an earlier stage in the cell cycle, driving cells out of the G1 phase and into the more active S phase.
In the study of Lammer (1998), injection of anti-body against Cdc25B caused cells to arrest after they reach
G2 phase. Dineli et al.
The best described action of CDT is its ability to inhibit cell cycle progression by blocking intoxicated cells in
G2 phase (8).
Cells go through 3 phases before they divide: the G1 phase, in which the cell grows and makes protein; the S phase, in which the cell makes DNA and replicates its chromosomes; and the
G2 phase, in which the cell prepares for division.
DNA duplication decreases but to a sufficient extent in the
G2 phase to the cell cycle.