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© The Rockefeller University Press,
0021-9525/2000//41 $5.00
The Journal of Cell Biology, Volume 149, Number 1,
, 2000 41-54
Original Article |
Structure and Assembly of the Nup84p Complex
cg5{at}ix.urz.uni-heidelberg.de
The Nup84p complex consists of five nucleoporins (Nup84p, Nup85p, Nup120p, Nup145p-C, and Seh1p) and Sec13p, a bona fide subunit of the COPII coat complex. We show that a pool of green fluorescent protein–tagged Sec13p localizes to the nuclear pores in vivo, and identify sec13 mutant alleles that are synthetically lethal with nup85
and affect the localization of a green fluorescent protein–Nup49p reporter protein. In the electron microscope, sec13 mutants exhibit structural defects in nuclear pore complex (NPC) and nuclear envelope organization. For the assembly of the complex, Nup85p, Nup120p, and Nup145p-C are essential. A highly purified Nup84p complex was isolated from yeast under native conditions and its molecular mass was determined to be 375 kD by quantitative scanning transmission electron microscopy and analytical ultracentrifugation, consistent with a monomeric complex. Furthermore, the Nup84p complex exhibits a Y-shaped, triskelion-like morphology 25 nm in diameter in the transmission electron microscope. Thus, the Nup84p complex constitutes a paradigm of an NPC structural module with distinct composition, structure, and a role in nuclear mRNA export and NPC bio- genesis.
Key Words: nuclear pore complex nuclear envelope Nup84p Sec13p electron microscopy
© 2000 The Rockefeller University Press
The present address of S. Siniossoglou and H. Santos-Rosa is Medical Research Council Laboratory of Molecular Biology, Division of Cell Biology, Hills Road, Cambridge CB2 2QH, UK.Abbreviations used in this paper: GFP, green fluorescent protein; NPC, nuclear pore complex; ProtA, protein A; STEM, scanning transmission EM; TEV, tobacco etch virus; ts, temperature-sensitive.
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