Abstract
Asymmetric cell divisions allow stem cells to balance proliferation and differentiation. During embryogenesis, murine epidermis expands rapidly from a single layer of unspecified basal layer progenitors to a stratified, differentiated epithelium. Morphogenesis involves perpendicular (asymmetric) divisions and the spindle orientation protein LGN, but little is known about how the apical localization of LGN is regulated. Here, we combine conventional genetics and lentiviral-mediated in vivo RNAi to explore the functions of the LGN-interacting proteins Par3, mInsc and Gαi3. Whereas loss of each gene alone leads to randomized division angles, combined loss of Gnai3 and mInsc causes a phenotype of mostly planar divisions, akin to loss of LGN. These findings lend experimental support for the hitherto untested model that Par3-mInsc and Gαi3 act cooperatively to polarize LGN and promote perpendicular divisions. Finally, we uncover a developmental switch between delamination-driven early stratification and spindle-orientation-dependent differentiation that occurs around E15, revealing a two-step mechanism underlying epidermal maturation.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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Animals
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Body Patterning
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Carrier Proteins / antagonists & inhibitors
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Carrier Proteins / genetics
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Carrier Proteins / physiology*
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Cell Adhesion Molecules / antagonists & inhibitors
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Cell Adhesion Molecules / genetics
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Cell Adhesion Molecules / physiology*
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Cell Cycle Proteins / antagonists & inhibitors
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / physiology*
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Cell Differentiation / genetics
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Cell Differentiation / physiology
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Cell Division / genetics
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Cell Division / physiology
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Epidermal Cells*
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Epidermis / embryology
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Epidermis / physiology*
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Female
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GTP-Binding Protein alpha Subunit, Gi2 / antagonists & inhibitors
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GTP-Binding Protein alpha Subunit, Gi2 / genetics
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GTP-Binding Protein alpha Subunit, Gi2 / physiology
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GTP-Binding Protein alpha Subunits, Gi-Go / antagonists & inhibitors
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GTP-Binding Protein alpha Subunits, Gi-Go / genetics
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GTP-Binding Protein alpha Subunits, Gi-Go / physiology*
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Gene Expression Regulation, Developmental
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Gene Knockdown Techniques
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Male
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Mice
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Mice, 129 Strain
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Mice, Inbred C57BL
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Mice, Transgenic
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Models, Biological
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Pregnancy
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RNA Interference
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Spindle Apparatus / physiology
Substances
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Adaptor Proteins, Signal Transducing
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Carrier Proteins
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Cell Adhesion Molecules
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Cell Cycle Proteins
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LGN protein, mouse
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Pard3 protein, mouse
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inscuteable protein, mouse
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GTP-Binding Protein alpha Subunit, Gi2
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GTP-Binding Protein alpha Subunits, Gi-Go
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Gnai2 protein, mouse
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Gnai3 protein, mouse