During the M-phase (mitosis) of the cell cycle, the nuclear envelope breaks down to allow the separation of replicated chromosomes and subsequent division.
When the chromosomes have been divided during the M-phase and the spindle fibers, have retracted, the nuclear envelope reforms around these separate sets.
The nuclear envelope must undergo several events before being rebuilt, including decondensation and reassembly of the nuclear lamina.
During the prophase of mitosis, chromosomes condense to facilitate alignment and separation, but during subsequent steps of mitosis, they de-condense and return to their extended, non-condensed state.
Decondensation allows condensed chromatin structures to relax and disperse. At the same time, the nuclear lamina, which supports the atomic envelope structurally, undergoes disassembly during early mitosis.
In contrast, as the chromosomes de-condense and the nuclear envelope reforms during late mitosis, the nuclear lamina reassembles during late mitosis, helping to rebuild the nuclear envelope structure.
The correct answer is Decondensation from chromosomes and reassembly of the nuclear lamina.
