JCB logo
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents

This Article
Right arrow Full Text (PDF, 4140K)
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Macaulay, C.
Right arrow Articles by Forbes, D. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Macaulay, C.
Right arrow Articles by Forbes, D. J.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

The Journal of Cell Biology, Vol 132, 5-20, Copyright © 1996 by The Rockefeller University Press


ARTICLES

Assembly of the nuclear pore: biochemically distinct steps revealed with NEM, GTP gamma S, and BAPTA

C Macaulay and DJ Forbes
Department of Biology, University of California San Diego, La Jolla 92093-0347, USA.

A key event in nuclear formation is the assembly of functional nuclear pores. We have used a nuclear reconstitution system derived from Xenopus eggs to examine the process of nuclear pore assembly in vitro. With this system, we have identified three reagents which interfere with nuclear pore assembly, NEM, GTP gamma S, and the Ca++ chelator, BAPTA. These reagents have allowed us to determine that the assembly of a nuclear pore requires the prior assembly of a double nuclear membrane. Inhibition of nuclear vesicle fusion by pretreatment of the membrane vesicle fraction with NEM blocks pore complex assembly. In contrast, NEM treatment of already fused double nuclear membranes does not block pore assembly. This indicates that NEM inhibits a single step in pore assembly--the initial fusion of vesicles required to form a double nuclear membrane. The presence of GTP gamma S blocks pore assembly at two distinct steps, first by preventing fusion between nuclear vesicles, and second by blocking a step in pore assembly that occurs on already fused double nuclear membranes. Interestingly, when the Ca2+ chelator BAPTA is added to a nuclear assembly reaction, it only transiently blocks nuclear vesicle fusion, but completely blocks nuclear pore assembly. This results in the formation of a nucleus surrounded by a double nuclear membrane, but devoid of nuclear pores. To order the positions at which GTP gamma S and BAPTA interfere with pore assembly, a novel anchored nuclear assembly assay was developed. This assay revealed that the BAPTA-sensitive step in pore assembly occurs after the second GTP gamma S-sensitive step. Thus, through use of an in vitro nuclear reconstitution system, it has been possible to biochemically define and order multiple steps in nuclear pore assembly.
Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents