title: Xath5 regulates neurogenesis in the Xenopus olfactory placode.
abstract: Helix-loop-helix (HLH) genes function as important regulators of neurogenesis in both the peripheral and central nervous systems. The olfactory system is an ideal tissue in which to study the role of these genes in regulating the acquisition of neuronal cell fate, particularly that of the olfactory receptor neuron (ORN). Here we describe the expression of several basic HLH (bHLH) and repeat HLH (rHLH) factors during olfactory placode development in Xenopus laevis. Our work reveals that a combination of both bHLH and rHLH genes are sequentially expressed within the nascent olfactory placode during normal development. Moreover, overexpression of the bHLH factor, Xenopus atonal homologue 5 (Xath5), promotes olfactory neural fate independent of cellular proliferation within a restricted domain at the anterior of the embryo. Collectively, our data argue that HLH genes are expressed in a cascade during olfactory placode development and that the activity of an atonal homologue, Xath5, can promote ORN fate but only in the appropriate developmental context.
authors.affiliation: Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah 84132-3401, USA.
authors.forename: Carole J
authors.initials: CJ
authors.lastname: Burns
authors.forename: Monica L
authors.initials: ML
authors.lastname: Vetter
mesh_terms: D000818:Animals; D016590:Aphidicolin / Q000494:pharmacology; D051792:Basic Helix-Loop-Helix Proteins; D002455:Cell Division; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005136:Eye Proteins / Q000378:metabolism* / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D005819:Genetic Markers; D006918:Hydroxyurea / Q000494:pharmacology; D017403:In Situ Hybridization; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000378:metabolism*; D009832:Olfactory Nerve / Q000196:embryology* / Q000502:physiology*; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism* / Q000502:physiology*; D014981:Xenopus / Q000196:embryology* / Q000502:physiology*; D029867:Xenopus Proteins
chemical_list: D016590:Aphidicolin; D051792:Basic Helix-Loop-Helix Proteins; D004791:Enzyme Inhibitors; D005136:Eye Proteins; D005819:Genetic Markers; D006918:Hydroxyurea; D014157:Transcription Factors; D029867:Xenopus Proteins; C109416:ATOH7 protein, Xenopus