Localized repressors delineate the neurogenic ectoderm in the early Drosophila embryo. Author Angelike Stathopoulos, Michael Levine Publication Year 2005 Type Journal Article Abstract The Dorsal gradient produces sequential patterns of gene expression across the dorsoventral axis of early embryos, thereby establishing the presumptive mesoderm, neuroectoderm, and dorsal ectoderm. Spatially localized repressors such as Snail and Vnd exclude the expression of neurogenic genes in the mesoderm and ventral neuroectoderm, respectively. However, no repressors have been identified that establish the dorsal limits of neurogenic gene expression. To investigate this issue, we have conducted an analysis of the ind gene, which is selectively expressed in lateral regions of the presumptive nerve cord. A novel silencer element was identified within the ind enhancer that is essential for eliminating expression in the dorsal ectoderm. Evidence is presented that the associated repressor can function over long distances to silence neighboring enhancers. The ind enhancer also contains a variety of known activator and repressor elements. We propose a model whereby Dorsal and EGF signaling, together with the localized Schnurri repressor, define a broad domain of ind expression throughout the entire presumptive neuroectoderm. The ventral limits of gene expression are defined by the Snail and Vnd repressors, while the dorsal border is established by the newly defined silencer element. Keywords Animals, Drosophila, Gene Expression Regulation, Developmental, Embryo, Nonmammalian, Models, Genetic, Base Sequence, In Situ Hybridization, Molecular Sequence Data, Enhancer Elements, Genetic, Lac Operon, Drosophila melanogaster, Computational Biology, Body Patterning, Mesoderm, Binding Sites, Neurons, Sequence Homology, Nucleic Acid, Ectoderm, Gene Silencing, RNA, Oligonucleotides, Antisense, Plasmids, Amino Acid Motifs Journal Dev Biol Volume 280 Issue 2 Pages 482-93 Date Published 04/2005 Alternate Journal Dev. Biol. Google ScholarBibTeXEndNote X3 XML