title: Robust control of mitotic spindle orientation in the developing epidermis.
abstract: Progenitor cells must balance self-amplification and production of differentiated progeny during development and homeostasis. In the epidermis, progenitors divide symmetrically to increase surface area and asymmetrically to promote stratification. In this study, we show that individual epidermal cells can undergo both types of division, and therefore, the balance is provided by the sum of individual cells' choices. In addition, we define two control points for determining a cell's mode of division. First is the expression of the mouse Inscuteable gene, which is sufficient to drive asymmetric cell division (ACD). However, there is robust control of division orientation as excessive ACDs are prevented by a change in the localization of NuMA, an effector of spindle orientation. Finally, we show that p63, a transcriptional regulator of stratification, does not control either of these processes. These data have uncovered two important regulatory points controlling ACD in the epidermis and allow a framework for analysis of how external cues control this important choice.
authors.affiliation: Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Poulson
authors.forename: Terry
authors.initials: T
authors.lastname: Lechler
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins; D002454:Cell Differentiation; D002455:Cell Division; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism / Q000648:ultrastructure*; D005455:Fluorescent Antibody Technique; D051379:Mice; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism / Q000648:ultrastructure*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C489080:Numa1 protein, mouse; D010750:Phosphoproteins