title: Pax2 modulates proliferation during specification of the otic and epibranchial placodes.
abstract: BACKGROUND
  The inner ear and epibranchial ganglia of vertebrates arise from a shared progenitor domain that is induced by FGF signalling, the posterior placodal area (PPA), before being segregated by Wnt signalling. One of the first genes activated in the PPA is the transcription factor Pax2. Loss-of- and gain-of function studies have defined a role for Pax2 in placodal morphogenesis and later inner ear development, but have not addressed the role Pax2 plays during the formation and maintenance of the PPA.
  
  
  RESULTS
  To understand the role of Pax2 during the development of the PPA, we used over-expression and repression of Pax2. Both gave rise to a smaller otocyst and repressed the formation of epibranchial placodes. In addition, cell cycle analysis revealed that Pax2 suppression reduced proliferation of the PPA.
  
  
  CONCLUSIONS
  Our results suggest that Pax2 functions in the maintenance but not the induction of the PPA. One role of Pax2 is to maintain proper cell cycle proliferation in the PPA.
authors.affiliation: Laboratory for Sensory Development, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, Japan.
authors.forename: Sabine
authors.initials: S
authors.lastname: Freter
authors.forename: Yuko
authors.initials: Y
authors.lastname: Muta
authors.forename: Paul
authors.initials: P
authors.lastname: O'Neill
authors.forename: Vassil S
authors.initials: VS
authors.lastname: Vassilev
authors.forename: Shigehiro
authors.initials: S
authors.lastname: Kuraku
authors.forename: Raj K
authors.initials: RK
authors.lastname: Ladher
mesh_terms: D000818:Animals; D002642:Chick Embryo; D018274:Electroporation; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051762:PAX2 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D051761:Paired Box Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D051762:PAX2 Transcription Factor; D051761:Paired Box Transcription Factors