High-resolution three-dimensional mapping of mRNA export through the nuclear pore

Area of Science:

• Cell Biology
• Molecular Biology
• Biophysics

Background:

• Nucleocytoplasmic transport of messenger RNA:protein complexes (mRNPs) regulates genetic information flow.
• The precise 3D pathway, kinetics, and selectivity of mRNP transit through nuclear pore complexes (NPCs) remain largely unknown.

Purpose of the Study:

• To elucidate the mechanism of nuclear mRNP export in live human cells.
• To investigate the three-dimensional (3D) pathway and transport dynamics of mRNPs through the NPC.

Main Methods:

• Utilized single-molecule fluorescence microscopy with high spatiotemporal resolution (8 nm, 2 ms).
• Performed 3D reconstruction of mRNP export routes in live human cells.

Main Results:

• Observed deceleration and selection of mRNPs at the NPC center.
• Characterized a fast-slow-fast diffusion pattern during the ~12 ms NPC interaction.
• Reconstructed a 3D export route showing interaction with NPC periphery and center, avoiding the central conduit.

Conclusions:

• mRNPs navigate a specific peripheral and central pathway within the NPC, distinct from small molecule diffusion channels.
• The study provides unprecedented spatiotemporal insights into the selective and dynamic process of mRNP nuclear export.