题名：Asymmetric Inheritance of Mother Versus Daughter Centrosome in Stem Cell Division
作者：Yukiko M. Yamashita, Anthony P. Mahowald, Julie R. Perlin, Margaret T. Fuller.
来源：Science[IF=30.927], 26 January 2007, Vol. 315. no. 5811, pp. 518 - 521, reports
摘要： Yukiko M. Yamashita,1* Anthony P. Mahowald,2 Julie R. Perlin,1 Margaret T. Fuller1,3
1 Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA 94305C5329, USA.
2 Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA.
3 Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305C5329, USA.
* Present address: Life Sciences Institute, Room 5403, University of Michigan, Ann Arbor, 210 Washtenaw Avenue, Ann Arbor, MI 48183C2216, USA.
To whom correspondence should be addressed. E-mail: firstname.lastname@example.org (Y.M.Y.); email@example.com (M.T.F.)
Adult stem cells often divide asymmetrically to produce one self-renewed stem cell and one differentiating cell, thus maintaining both populations. The asymmetric outcome of stem cell divisions can be specified by an oriented spindle and local self-renewal signals from the stem cell niche. Here we show that developmentally programmed asymmetric behavior and inheritance of mother and daughter centrosomes underlies the stereotyped spindle orientation and asymmetric outcome of stem cell divisions in the Drosophila male germ line. The mother centrosome remains anchored near the niche while the daughter centrosome migrates to the opposite side of the cell before spindle formation.
Adult stem cells maintain populations of highly differentiated but short-lived cells throughout the life of the organism. To maintain the critical balance between stem cell and differentiating cell populations, stem cells have a potential to divide asymmetrically, producing one stem and one differentiating cell (1). The asymmetric outcome of stem cell divisions can be specified by regulated spindle orientation, such that the two daughter cells are placed in different microenvironments that either specify stem cell identity (stem cell niche) or allow differentiation (2, 3).
Drosophila male germline stem cells (GSCs) are maintained through attachment to somatic hub cells, which constitute the stem cell niche. Hub cells secrete the signaling ligand Upd, which activates the Janus kinaseCsignal transducer and activator of transcription (JAK-STAT) pathway in the neighboring germ cells to specify stem cell identity (4, 5). Drosophila male GSCs normally divide asymmetrically, producing one stem cell, which remains attached to the hub, and one gonialblast, which initiates differentiation. This stereotyped asymmetric outcome is controlled by the orientation of the mitotic spindle in GSCs: The spindle lies perpendicular to the hub so that one daughter cell inherits the attachment to the hub, whereas the other is displaced away (6). ... 4