Assembly of higher order Nup107–160 structures, visualized by imaging Seh1 or Nup37, is restricted to the nascent nuclear envelope membrane. (A) 2D time lapse from a mitotic HeLa cell coexpressing GFP-Seh1 and mCherry-Sec61β showing the recruitment of Seh1 (closed arrowheads) onto the nuclear envelope. (B) 2D time lapse from a mitotic HeLa cell coexpressing GFP-Nup37 and mCherry-Sec61β showing the recruitment of Nup37 (closed arrowheads) onto the nuclear envelope. Open arrowheads indicate kinetochores. See legend of Fig 5 (C and D) for a detailed description. Boxes in A and B are enlarged at the bottom. Bars, 10 µm.