title: Maternal Oct1/2 is required for Nodal and Vg1/Univin expression during dorsal-ventral axis specification in the sea urchin embryo.
abstract: The TGFβ family member Nodal is expressed early in the presumptive ventral ectoderm of the early sea urchin embryo and its activity is crucial for dorsal-ventral (D/V) axis specification. Analysis of the nodal promoter identified a number of critical binding sites for transcription factors of different families including Sox, Oct, TCF and bZIP, but in most cases the specific factors that regulate nodal expression are not known. In this study, we report that the maternal factor Oct1/2 functions as a positive regulator of nodal and that its activity is essential for the initiation of nodal expression. Inhibition of Oct1/2 mRNA translation produced embryos with severe axial defects similar to those observed following inhibition of Nodal function. We show that perturbing Oct1/2 function specifically disrupted specification of the ventral and dorsal ectodermal regions and that these effects were caused by the failure of nodal to be expressed early in development. Furthermore, we identified the key gene vg1/univin, which is also necessary for nodal expression, as an additional factor that was completely dependent on Oct1/2 for its zygotic expression. These data demonstrate that the maternal Oct1/2 protein plays an early and essential role in D/V axis specification by initiating the expression of nodal and vg1/univin, two genes that act at the top of the D/V ectoderm gene regulatory network.
authors.affiliation: Université Pierre et Marie Curie (Paris 6), UMR 7009 CNRS, Observatoire Océanologique, 06230 Villefranche-sur-mer, France.
authors.forename: Ryan
authors.initials: R
authors.lastname: Range
authors.forename: Thierry
authors.initials: T
authors.lastname: Lepage
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000235:genetics*; D004475:Ectoderm / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D053263:Gene Regulatory Networks / Q000235:genetics; D008954:Models, Biological; D055457:Nodal Protein / Q000235:genetics* / Q000378:metabolism; D050811:Octamer Transcription Factor-1 / Q000235:genetics / Q000378:metabolism*; D050813:Octamer Transcription Factor-2 / Q000235:genetics / Q000378:metabolism*; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D012617:Sea Urchins / Q000166:cytology / Q000187:drug effects / Q000196:embryology* / Q000235:genetics; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D015053:Zygote / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D055457:Nodal Protein; D050811:Octamer Transcription Factor-1; D050813:Octamer Transcription Factor-2; D016376:Oligonucleotides, Antisense; D016212:Transforming Growth Factor beta; C090547:univin