title: Foxa2 regulates the expression of Nato3 in the floor plate by a novel evolutionarily conserved promoter.
abstract: The development of the neural tube into a complex central nervous system involves morphological, cellular and molecular changes, all of which are tightly regulated. The floor plate (FP) is a critical organizing center located at the ventral-most midline of the neural tube. FP cells regulate dorsoventral patterning, differentiation and axon guidance by secreting morphogens. Here we show that the bHLH transcription factor Nato3 (Ferd3l) is specifically expressed in the spinal FP of chick and mouse embryos. Using in ovo electroporation to understand the regulation of the FP-specific expression of Nato3, we have identified an evolutionarily conserved 204 bp genomic region, which is necessary and sufficient to drive expression to the chick FP. This promoter contains two Foxa2-binding sites, which are highly conserved among distant phyla. The two sites can bind Foxa2 in vitro, and are necessary for the expression in the FP in vivo. Gain and loss of Foxa2 function in vivo further emphasize its role in Nato3 promoter activity. Thus, our data suggest that Nato3 is a direct target of Foxa2, a transcription activator and effector of Sonic hedgehog, the hallmark regulator of FP induction and spinal cord development. The identification of the FP-specific promoter is an important step towards a better understanding of the molecular mechanisms through which Nato3 transcription is regulated and for uncovering its function during nervous system development. Moreover, the promoter provides us with a powerful tool for conditional genetic manipulations in the FP.
authors.affiliation: Department of Cell and Developmental Biology, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel.
authors.forename: Abed AlFatah
authors.initials: AA
authors.lastname: Mansour
authors.forename: Einat
authors.initials: E
authors.lastname: Nissim-Eliraz
authors.forename: Sophie
authors.initials: S
authors.lastname: Zisman
authors.forename: Tamar
authors.initials: T
authors.lastname: Golan-Lev
authors.forename: Omri
authors.initials: O
authors.lastname: Schatz
authors.forename: Avihu
authors.initials: A
authors.lastname: Klar
authors.forename: Nissim
authors.initials: N
authors.lastname: Ben-Arie
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002642:Chick Embryo; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D051542:Hepatocyte Nuclear Factor 3-beta / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D054259:Neural Tube / Q000033:anatomy & histology* / Q000502:physiology*; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins; D016415:Sequence Alignment; D013116:Spinal Cord / Q000033:anatomy & histology / Q000196:embryology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: C499046:Ferd3l protein, mouse; C496503:Foxa2 protein, mouse; D009419:Nerve Tissue Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D051542:Hepatocyte Nuclear Factor 3-beta