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

This Article Full Text (PDF, 529K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Social Bookmarking                            What's this?

© The Rockefeller University Press, 0021-9525/2003/9/1181 $5.00
The Journal of Cell Biology, Volume 162, Number 7, 1181-1181

Centrosomes lead stem cell orientation

A spindle perpendicular to the hub ensures one GSC progeny differentiates and one remains a stem cell. Fuller/AAAS

Stem cells in the fly male germ line can both maintain their numbers and produce differentiating progeny by correctly orienting cell division, according to Yukiko Yamashita, D. Leanne Jones, and Margaret Fuller (Stanford University, Stanford, CA).

Asymmetric cell division is associated with control over spindle orientation in several models, such as the fly neuroblast and the worm P1 cell. In both of these cases, the spindle is reoriented during mitosis. But in fly germline stem cells (GSCs), which divide asymmetrically to produce one stem cell and one cell that initiates differentiation, Fuller's group now shows that the GSCs are oriented throughout the cell cycle, not just during mitosis.GSCs align themselves with the surface of their niche, known as the hub—a cluster of somatic cells in the testes that instruct neighboring GSCs to retain stem cell identity. Yamashita et al. show that GSCs build their spindle perpendicular to the hub by keeping one centrosome in close contact with the hub—even during interphase. After the cell divides, one daughter remains connected to the hub, and thus maintains stem cell identity, whereas the other daughter is displaced away and differentiates. Disruption of centrosome function interferes with this polarity. As a result, both daughter cells contact the hub, leading to an excess of GSCs.

The boundary between the hub and the GSC contained high levels of cadherins and a fly homologue of APC, which is thought to help orient spindles in epithelial cells. APC mutant GSCs have mispositioned centrosomes, misoriented spindles, and an excess of GSCs. Thus, the APC–cadherin complex may anchor one GSC centrosome near the hub, leaving the other free to roam.

Reference:

Yamashita, Y.M., et al. 2003. Science. 301:1547–1550.[Abstract/Free Full Text]

Nicole LeBrasseur

lebrasn{at}rockefeller.edu

CiteULike    Complore    Connotea    Del.icio.us    Digg    Facebook    Reddit    Technorati    Twitter    What's this?

This Article Full Text (PDF, 529K) PPT slides of all figures Alert me when this article is cited Services Email this article Similar articles in this journal Alert me to new content in the JCB Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by LeBrasseur, N. Search for Related Content PubMed Articles by LeBrasseur, N. Social Bookmarking                            What's this?