title: Cooperative action of multiple cis-acting elements is required for N-myc expression in branchial arches: specific contribution of GATA3.
abstract: The precise expression of the N-myc proto-oncogene is essential for normal mammalian development, whereas altered N-myc gene regulation is known to be a determinant factor in tumor formation. Using transgenic mouse embryos, we show that N-myc sequences from kb -8.7 to kb +7.2 are sufficient to reproduce the N-myc embryonic expression profile in developing branchial arches and limb buds. These sequences encompass several regulatory elements dispersed throughout the N-myc locus, including an upstream limb bud enhancer, a downstream somite enhancer, a branchial arch enhancer in the second intron, and a negative regulatory element in the first intron. N-myc expression in the limb buds is under the dominant control of the limb bud enhancer. The expression in the branchial arches necessitates the interplay of three regulatory domains. The branchial arch enhancer cooperates with the somite enhancer region to prevent an inhibitory activity contained in the first intron. The characterization of the branchial arch enhancer has revealed a specific role of the transcription factor GATA3 in the regulation of N-myc expression. Together, these data demonstrate that correct N-myc developmental expression is achieved via cooperation of multiple positive and negative regulatory elements.
authors.affiliation: Centre de Recherche en Cancérologie de l'Université Laval, 9 rue McMahon, Québec, QC, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Potvin
authors.forename: Laurent
authors.initials: L
authors.lastname: Beuret
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Cadrin-Girard
authors.forename: Marcelle
authors.initials: M
authors.lastname: Carter
authors.forename: Sophie
authors.initials: S
authors.lastname: Roy
authors.forename: Michel
authors.initials: M
authors.lastname: Tremblay
authors.forename: Jean
authors.initials: J
authors.lastname: Charron
mesh_terms: D000818:Animals; D001483:Base Sequence; D001934:Branchial Region / Q000033:anatomy & histology / Q000196:embryology* / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000033:anatomy & histology / Q000502:physiology; D050990:GATA3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D016259:Genes, myc; D006801:Humans; D017403:In Situ Hybridization; D007438:Introns; D018878:Limb Buds / Q000033:anatomy & histology / Q000196:embryology / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism*; D012045:Regulatory Sequences, Nucleic Acid; D016415:Sequence Alignment
chemical_list: D050990:GATA3 Transcription Factor; C494748:Gata3 protein, mouse; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc