The conserved Nup107-160 complex is critical for nuclear pore complex assembly

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Nuclear pore complexes (NPCs) regulate transport between the nucleus and cytoplasm.
• The nuclear envelope (NE) and NPCs disassemble during mitosis in higher eukaryotes.
• NPC reassembly post-mitosis is not well understood.

Purpose of the Study:

• To investigate the role of the Nup107-160 complex in NPC reassembly after mitosis.
• To elucidate the mechanism of NPC incorporation into the reforming nuclear envelope.

Main Methods:

• RNA interference (RNAi) for in vivo depletion of Nup133 and Nup107 in HeLa cells.
• Immunodepletion of the Nup107-160 complex in in vitro nuclear assembly assays.
• Analysis of nucleoporin levels, NPC density, and FG-repeat nucleoporin association with chromatin.

Main Results:

• Depletion of Nup133 or Nup107 reduced nucleoporin levels and NPC density.
• Complete Nup107-160 complex depletion prevented NPC formation during in vitro nuclear assembly.
• Readdition of the Nup107-160 complex before closed NE formation rescued NPC assembly.
• Nup107-160 complex depletion inhibited FG-repeat nucleoporin association with chromatin.

Conclusions:

• The Nup107-160 complex plays a critical role in post-mitotic NPC assembly.
• NPC assembly initiates with the recruitment of the Nup107-160 complex to chromatin.
• This complex is essential for the proper incorporation of NPCs into the reforming nuclear envelope.