title: Spatiotemporal expression of Zic genes during vertebrate inner ear development.
abstract: BACKGROUND
  Inner ear development involves signaling from surrounding tissues, including the adjacent hindbrain, periotic mesenchyme, and notochord. These signals include SHH, FGFs, BMPs, and WNTs from the hindbrain and SHH from the notochord. Zic genes, which are expressed in the dorsal neural tube and act during neural development, have been implicated as effectors of these pathways. This report examines whether Zic genes' involvement in inner ear development is a tenable hypothesis based on their expression patterns.
  
  
  RESULTS
  In the developing inner ear of both the chick and mouse, all of the Zic genes were expressed in the dorsal neural tube and variably in the periotic mesenchyme, but expression of the Zic genes in the otic epithelium was not found. The onset of expression differed among the Zic genes; within any given region surrounding the otic epithelium, multiple Zic genes were expressed in the same place at the same time.
  
  
  CONCLUSIONS
  Zic gene expression in the region of the developing inner ear is similar between mouse and chick. Zic expression domains overlap with sites of WNT and SHH signaling during otocyst patterning, suggesting a role for Zic genes in modulating signaling from these pathways.
authors.affiliation: Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Chervenak
authors.forename: Ibrahim S
authors.initials: IS
authors.lastname: Hakim
authors.forename: Kate F
authors.initials: KF
authors.lastname: Barald
mesh_terms: D000818:Animals; D002642:Chick Embryo; D002645:Chickens; D007758:Ear, Inner / Q000196:embryology* / Q000378:metabolism*; D047108:Embryonic Development / Q000235:genetics / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D051762:PAX2 Transcription Factor / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014714:Vertebrates / Q000196:embryology* / Q000378:metabolism*
chemical_list: D018398:Homeodomain Proteins; D051762:PAX2 Transcription Factor; C497319:Pax2 protein, mouse; D014157:Transcription Factors; C492122:Zic1 protein, mouse; C491811:Zic2 protein, mouse; C491594:Zic3 protein, mouse; C100431:Zic4 protein, mouse