title: The two Tribolium E(spl) genes show evolutionarily conserved expression and function during embryonic neurogenesis.
abstract: Tribolium castaneum is a well-characterised model insect, whose short germ-band mode of embryonic development is characteristic of many insect species and differs from the exhaustively studied Drosophila. Mechanisms of early neurogenesis, however, show significant conservation with Drosophila, as a characteristic pattern of neuroblasts arises from neuroectoderm proneural clusters in response to the bHLH activator Ash, a homologue of Achaete-Scute. Here we study the expression and function of two other bHLH proteins, the bHLH-O repressors E(spl)1 and E(spl)3. Their Drosophila homologues are expressed in response to Notch signalling and antagonize the activity of Achaete-Scute proteins, thus restricting the number of nascent neuroblasts. E(spl)1 and 3 are the only E(spl) homologues in Tribolium and both show expression in the cephalic and ventral neuroectoderm during embryonic neurogenesis, as well as a dynamic pattern of expression in other tissues. Their expression starts early, soon after Ash expression and is dependent on both Ash and Notch activities. They act redundantly, since a double E(spl) knockdown (but not single knockdowns) results in neurogenesis defects similar to those caused by Notch loss-of-function. A number of other activities have been evolutionarily conserved, most notably their ability to interact with proneural proteins Scute and Daughterless.
authors.affiliation: Institute of Molecular Biology & Biotechnology, Foundation for Research & Technology Hellas and Department of Biology, University of Crete, Heraklion, Crete, Greece.
authors.forename: Kristina
authors.initials: K
authors.lastname: Kux
authors.forename: Marianthi
authors.initials: M
authors.lastname: Kiparaki
authors.forename: Christos
authors.initials: C
authors.lastname: Delidakis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017124:Conserved Sequence / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics; D004475:Ectoderm / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000378:metabolism; D047108:Embryonic Development / Q000235:genetics*; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D017344:Genes, Insect / Q000235:genetics*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D055495:Neurogenesis / Q000235:genetics*; D010802:Phylogeny; D051880:Receptors, Notch / Q000378:metabolism; D019076:Transgenes; D014231:Tribolium / Q000235:genetics*
chemical_list: D019476:Insect Proteins; D051880:Receptors, Notch