Does the nuclear envelope retain its identity during mitosis?

During mitosis in metazoan species, the nuclear envelope (NE) undergoes breakdown, and its fragments are absorbed within the membranous network of the endoplasmic reticulum (ER). Past observations by fluorescence microscopy led researchers to think that the NE loses its identity when it is absorbed within the ER membrane. However, in our previous work, we developed a more specific labelling method and found evidence that the NE does not completely lose its identity during mitosis. In the present work, we conduct further experiments, the results of which support the idea that the NE partially retains its identity during mitosis.