reshaping endoplasmic reticulum into nuclear envelop via ER flatting

Paul Clarke
University of Dundee, United Kingdom
Cell Biology

This article provides strong evidence for the role of the endoplasmic reticulum (ER) in the formation of the nuclear envelope (NE). Anderson and Hetzer show that nuclear envelope formation during mitosis in human U2OS cells involves the recruitment of ER tubules to chromatin after chromosome segregation. This process is restrained by the ER-tubule shaping proteins reticulon 3, reticulon 4 and DP1, indicating that the flattening of ER tubules is important for the formation of the NE. This work strengthens the view that dissolution of the NE during mitosis in metazoan somatic cells with an open mitosis involves retraction into the ER rather than disintegration into vesicles.

Competing interests: None declared
Evaluated 17 Sep 2008

As stated by the F1000 review, this study has done a very good job in describing the process how endoplasmic reticulum is shaped into nuclear envelop. The cell they were using is U2O2, and most methods used are very common in the lab.
My point is that there are still many un-touched biological questions for scientists to explore. The sky is open!

J Cell Biol. 2008 Sep 8;182(5):911-24.

Reshaping of the endoplasmic reticulum limits the rate for nuclear envelope formation.

Anderson DJ, Hetzer MW.

Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.

During mitosis in metazoans, segregated chromosomes become enclosed by the nuclear envelope (NE), a double membrane that is continuous with the endoplasmic reticulum (ER). Recent in vitro data suggest that NE formation occurs by chromatin-mediated reorganization of the tubular ER; however, the basic principles of such a membrane-reshaping process remain uncharacterized. Here, we present a quantitative analysis of nuclear membrane assembly in mammalian cells using time-lapse microscopy. From the initial recruitment of ER tubules to chromatin, the formation of a membrane-enclosed, transport-competent nucleus occurs within approximately 12 min. Overexpression of the ER tubule-forming proteins reticulon 3, reticulon 4, and DP1 inhibits NE formation and nuclear expansion, whereas their knockdown accelerates nuclear assembly. This suggests that the transition from membrane tubules to sheets is rate-limiting for nuclear assembly. Our results provide evidence that ER-shaping proteins are directly involved in the reconstruction of the nuclear compartment and that morphological restructuring of the ER is the principal mechanism of NE formation in vivo.

PMID: 18779370

Previous: 来一篇生态作品
Next: T-Mobile announced G1 with google today, the first phone based on Android