To answer your question: the nucleus has a membrane.
Answer: THEY ARE INVOLVED IN THE DISASSEMBLY OF THE NUCLEAR ENVELOPE
Explanation: The disassembly of the nuclear envelope is triggered by the cyclin‐dependent kinase at the onset of mitosis. At this point, Integral nuclear membrane proteins diffuse/move into the endoplasmic reticulum (ER) after nuclear envelope breakdown. The nuclear envelope reassembles around compact chromosome mass at late anaphase/telophase and the chromosomes condenses and become visible.
