TY - JOUR
T1 - Developmental roles for Srf, cortical cytoskeleton and cell shape in epidermal spindle orientation
AU - Luxenburg, Chen
AU - Amalia Pasolli, H.
AU - Williams, Scott E.
AU - Fuchs, Elaine
N1 - Funding Information:
We thank the RU Facilities for Bioimaging (A. North) and FACS (S. Mazel) staff for their technical support; we thank N. Stokes for her assistance in the mouse facility and the Comparative Biology Center (CBC) staff for their help in veterinary care and health of our mice. We are grateful to E. Ezratty, S. Beronja, A. R. Folgueras, M. Nikolova and other members of the Fuchs laboratory for helpful discussions, critical reading of the manuscript and experimental assistance. C.L. is a Tri-Institutional Starr Stem Cell Scholars Posdoctoral Fellow. S.E.W. is an American Cancer Society Postdoctoral Fellow. Work in the Fuchs laboratory was supported by a grant from the National Institutes of Health (E.F. R01AR27883).
PY - 2011/3
Y1 - 2011/3
N2 - During development, a polarized epidermal sheet undergoes stratification and differentiation to produce the skin barrier. Through mechanisms that are poorly understood, the process involves actin dynamics, spindle reorientation and Notch signalling. To elucidate how epidermal embryogenesis is governed, we conditionally targeted serum response factor (Srf), a transcription factor that is essential for epidermal differentiation. Unexpectedly, previously ascribed causative defects are not responsible for profoundly perturbed embryonic epidermis. Seeking the mechanism for this, we identified actins and their regulators that were downregulated after ablation. Without Srf, cells exhibit a diminished cortical network and in mitosis, they fail to round up, features we recapitulate with low-dose actin inhibitors in vivo and shRNA-knockdown in vitro. Altered concomitantly are phosphorylated ERM and cortical myosin-IIA, shown in vitro to establish a rigid cortical actomyosin network and elicit critical shape changes. We provide a link between these features and Srf loss, and we show that the process is physiologically relevant in skin, as reflected by defects in spindle orientation, asymmetric cell divisions, stratification and differentiation.
AB - During development, a polarized epidermal sheet undergoes stratification and differentiation to produce the skin barrier. Through mechanisms that are poorly understood, the process involves actin dynamics, spindle reorientation and Notch signalling. To elucidate how epidermal embryogenesis is governed, we conditionally targeted serum response factor (Srf), a transcription factor that is essential for epidermal differentiation. Unexpectedly, previously ascribed causative defects are not responsible for profoundly perturbed embryonic epidermis. Seeking the mechanism for this, we identified actins and their regulators that were downregulated after ablation. Without Srf, cells exhibit a diminished cortical network and in mitosis, they fail to round up, features we recapitulate with low-dose actin inhibitors in vivo and shRNA-knockdown in vitro. Altered concomitantly are phosphorylated ERM and cortical myosin-IIA, shown in vitro to establish a rigid cortical actomyosin network and elicit critical shape changes. We provide a link between these features and Srf loss, and we show that the process is physiologically relevant in skin, as reflected by defects in spindle orientation, asymmetric cell divisions, stratification and differentiation.
UR - http://www.scopus.com/inward/record.url?scp=79952282364&partnerID=8YFLogxK
U2 - 10.1038/ncb2163
DO - 10.1038/ncb2163
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AN - SCOPUS:79952282364
SN - 1465-7392
VL - 13
SP - 203
EP - 214
JO - Nature Cell Biology
JF - Nature Cell Biology
IS - 3
ER -