title: Genome-wide identification of Smad/Foxh1 targets reveals a role for Foxh1 in retinoic acid regulation and forebrain development.
abstract: Foxh1, a Smad DNA-binding partner, mediates TGFbeta-dependent gene expression during early development. Few Foxh1 targets are known. Here, we describe a genome-wide approach that we developed that couples systematic mapping of a functional Smad/Foxh1 enhancer (SFE) to Site Search, a program used to search annotated genomes for composite response elements. Ranking of SFEs that are positionally conserved across species yielded a set of genes enriched in Foxh1 targets. Analysis of top candidates, such as Hesx1, Lgr4, Lmo1, Fgf8, and members of the Aldh1a subfamily, revealed that Foxh1 initiates a transcriptional regulatory network within the developing anterior neuroectoderm. The Aldh1a family is required for retinoic acid (RA) synthesis, and, in Foxh1 mutants, expression of Aldh1a1, -2, and -3 and activation of a RA-responsive transgenic reporter is abolished in anterior structures. Integrated mapping of a developmental transcription factor network thus reveals a key role for Foxh1 in patterning and initiating RA signaling in the forebrain.
authors.affiliation: Institute of Medical Science, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada.
authors.forename: Cristoforo
authors.initials: C
authors.lastname: Silvestri
authors.forename: Masahiro
authors.initials: M
authors.lastname: Narimatsu
authors.forename: Ingo
authors.initials: I
authors.lastname: von Both
authors.forename: Yongmei
authors.initials: Y
authors.lastname: Liu
authors.forename: Nicholas B J
authors.initials: NB
authors.lastname: Tan
authors.forename: Luisa
authors.initials: L
authors.lastname: Izzi
authors.forename: Peter
authors.initials: P
authors.lastname: McCaffery
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Wrana
authors.forename: Liliana
authors.initials: L
authors.lastname: Attisano
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000235:genetics / Q000378:metabolism; D000080924:Aldehyde Dehydrogenase 1 Family; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002460:Cell Line; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004742:Enhancer Elements, Genetic; D051858:Forkhead Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D023281:Genomics; D006801:Humans; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D008954:Models, Biological; D016548:Prosencephalon / Q000196:embryology* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D050697:Retinal Dehydrogenase; D015398:Signal Transduction; D051785:Smad Proteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014212:Tretinoin / Q000378:metabolism*
chemical_list: D051858:Forkhead Transcription Factors; C491117:Foxh1 protein, mouse; D007527:Isoenzymes; D012333:RNA, Messenger; D051785:Smad Proteins; D014212:Tretinoin; D004247:DNA; D000080924:Aldehyde Dehydrogenase 1 Family; D000444:Aldehyde Dehydrogenase; C510223:ALDH1A1 protein, human; C515028:ALDH1A1 protein, mouse; D050697:Retinal Dehydrogenase