Rab11 regulates planar polarity and migratory behavior of multiciliated cells in Xenopus embryonic epidermis.
BACKGROUND
Xenopus embryonic skin is composed of the superficial layer with defined apicobasal polarity and the inner layer lacking the apical domain. Multiciliated cells (MCCs) originate in the inner layer of the epidermal ectoderm and subsequently migrate to the surface. How MCCs acquire the apicobasal polarity and intercalate into the superficial layer during neurulation is largely unknown. As Rab11-dependent vesicle trafficking has been implicated in ciliary membrane assembly and in apical domain formation in epithelial cells, we assessed the involvement of Rab11 in MCC development.


RESULTS
Here we report that Rab11 is specifically enriched and becomes apically polarized in skin MCCs. Interference with Rab11 function by overexpression of a dominant negative mutant or injection of a specific morpholino oligonucleotide inhibited MCC intercalation into the superficial layer. Dominant negative Rab11-expressing MCC precursors revealed intrinsic apicobasal polarity, characterized by the apical domain, which is not normally observed in inner layer cells. Despite the presence of the apical domain, the cells with inhibited Rab11 function were randomly oriented relative to the plane of the tissue, thereby demonstrating a defect in planar polarity.


CONCLUSIONS
These results establish a requirement for Rab11 in MCC development and support a two-step model, in which the initial polarization of MCC precursors is critical for their integration into the superficial cell layer.
Department of Developmental and Regenerative Biology, Mount Sinai School of Medicine, New York, NY 10029, USA.
Kyeongmi
K
Kim
Blue B
BB
Lake
Tomomi
T
Haremaki
Daniel C
DC
Weinstein
Sergei Y
SY
Sokol
D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D002465:Cell Movement / Q000235:genetics*; D016764:Cell Polarity / Q000235:genetics*; D002923:Cilia / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D004625:Embryo, Nonmammalian; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D000078404:Epidermal Cells; D004817:Epidermis / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D008954:Models, Biological; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D000099193:rab11 GTP-Binding Proteins
D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins