Distinct roles of Fgf8, Foxi1, Dlx3b and Pax8/2 during otic vesicle induction and maintenance in medaka.
The development of the vertebrate inner ear is a complex process that has been investigated in several model organisms. In this work, we examined genetic interactions regulating early development of otic structures in medaka. We demonstrate that misexpression of Fgf8, Dlx3b and Foxi1 during early gastrulation is sufficient to produce ectopic otic vesicles. Combined misexpression strongly increases the appearance of this phenotype. By using a heat-inducible promoter we were furthermore able to separate the regulatory interactions among Fgf8, Foxi1, Dlx3b, Pax8 and Pax2 genes, which are active during different stages of early otic development. In the preplacodal stage we suggest a central position of Foxi1 within a regulatory network of early patterning genes including Dlx3b and Pax8. Different pathways are active after the placodal stage with Dlx3b playing a central role. There Dlx3b regulates members of the Pax-Six-Eya-Dach network and also strongly affects the early dorsoventral marker genes Otx1 and Gbx2.
Aghaallaei
Narges
N
Institute of Animal Breeding and Genetics, University of Veterinary Medicine, Veterinärplatz 1, A-1210 Vienna, Austria.
Bajoghli
Baubak
B
Czerny
Thomas
T
D000818:Animals; D019521:Body Patterning / Q000235:genetics; D007758:Ear, Inner / Q000196:embryology* / Q000378:metabolism; D004627:Embryonic Induction / Q000235:genetics; D051524:Fibroblast Growth Factor 8 / Q000235:genetics*; D029941:Fish Proteins / Q000235:genetics*; D051858:Forkhead Transcription Factors / Q000235:genetics*; D005775:Gastrula / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics*; D017403:In Situ Hybridization; D009990:Oryzias / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism; D051762:PAX2 Transcription Factor / Q000235:genetics*; D051761:Paired Box Transcription Factors / Q000235:genetics*; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics*
C088334:Distal-less homeobox proteins; D029941:Fish Proteins; D051858:Forkhead Transcription Factors; D018398:Homeodomain Proteins; D051762:PAX2 Transcription Factor; D051761:Paired Box Transcription Factors; D014157:Transcription Factors; D051524:Fibroblast Growth Factor 8