title: Gene regulatory control in the sea urchin aboral ectoderm: spatial initiation, signaling inputs, and cell fate lockdown.
abstract: The regulation of oral-aboral ectoderm specification in the sea urchin embryo has been extensively studied in recent years. The oral-aboral polarity is initially imposed downstream of a redox gradient induced by asymmetric maternal distribution of mitochondria. Two TGF-β signaling pathways, Nodal and BMP, are then respectively utilized in the generation of oral and aboral regulatory states. However, a causal understanding of the regulation of aboral ectoderm specification has been lacking. In this work control of aboral ectoderm regulatory state specification was revealed by combining detailed regulatory gene expression studies, perturbation and cis-regulatory analyses. Our analysis illuminates a dynamic system where different factors dominate at different developmental times. We found that the initial activation of aboral genes depends directly on the redox sensitive transcription factor, hypoxia inducible factor 1α (HIF-1α). Two BMP ligands, BMP2/4 and BMP5/8, then significantly enhance aboral regulatory gene transcription. Ultimately, encoded feedback wiring lockdown the aboral ectoderm regulatory state. Our study elucidates the different regulatory mechanisms that sequentially dominate the spatial localization of aboral regulatory states.
authors.affiliation: Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa 31905, Israel. sben-tab@univ.haifa.ac.il
authors.forename: Smadar
authors.initials: S
authors.lastname: Ben-Tabou de-Leon
authors.forename: Yi-Hsien
authors.initials: YH
authors.lastname: Su
authors.forename: Kuan-Ting
authors.initials: KT
authors.lastname: Lin
authors.forename: Enhu
authors.initials: E
authors.lastname: Li
authors.forename: Eric H
authors.initials: EH
authors.lastname: Davidson
mesh_terms: D000818:Animals; D019521:Body Patterning; D019070:Cell Lineage; D004475:Ectoderm / Q000196:embryology* / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D049452:Green Fluorescent Proteins / Q000378:metabolism; D008954:Models, Biological; D009841:Oligonucleotides / Q000378:metabolism; D010084:Oxidation-Reduction; D016133:Polymerase Chain Reaction / Q000379:methods; D012333:RNA, Messenger / Q000378:metabolism; D012617:Sea Urchins; D015398:Signal Transduction; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism
chemical_list: D009841:Oligonucleotides; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D049452:Green Fluorescent Proteins