Re: Rough ER and Nuclear Envelope use the same membrane material?

The ER and the nuclear membrane are contiguous.  The membrane material of 
the cell is constantly recycling from the outer nuclear membrane, through 
the ER to the golgi apparatus and from there to to the plasma membrane 
during exocytosis.  This process of moving membranous vesicles from the 
nuclear membrane to the plasma membrane is balanced by the opposite 
process of endocytosis. (Alberts et al, Mol. Biology of the Cell, 3rd 
Edition, New York:  Garland Press, 1994).

Please remember that the nuclear membrane is disrupted during mitosis, but 
that otherwise it is intact.

I hope that this helps!  If this did not completely answer your question, 
please e-mail me back and I can go into more detail.

Ingrid Dodge :)