title: Orthodenticle is required for the development of olfactory projection neurons and local interneurons in Drosophila.
abstract: The accurate wiring of nervous systems involves precise control over cellular processes like cell division, cell fate specification, and targeting of neurons. The nervous system of Drosophila melanogaster is an excellent model to understand these processes. Drosophila neurons are generated by stem cell like precursors called neuroblasts that are formed and specified in a highly stereotypical manner along the neuroectoderm. This stereotypy has been attributed, in part, to the expression and function of transcription factors that act as intrinsic cell fate determinants in the neuroblasts and their progeny during embryogenesis. Here we focus on the lateral neuroblast lineage, ALl1, of the antennal lobe and show that the transcription factor-encoding cephalic gap gene orthodenticle is required in this lineage during postembryonic brain development. We use immunolabelling to demonstrate that Otd is expressed in the neuroblast of this lineage during postembryonic larval stages. Subsequently, we use MARCM clonal mutational methods to show that the majority of the postembryonic neuronal progeny in the ALl1 lineage undergoes apoptosis in the absence of orthodenticle. Moreover, we demonstrate that the neurons that survive in the orthodenticle loss-of-function condition display severe targeting defects in both the proximal (dendritic) and distal (axonal) neurites. These findings indicate that the cephalic gap gene orthodenticle acts as an important intrinsic determinant in the ALl1 neuroblast lineage and, hence, could be a member of a putative combinatorial code involved in specifying the fate and identity of cells in this lineage.
authors.affiliation: National Centre for Biological Sciences - Tata Institute of Fundamental Research, UAS-GKVK Campus, Bellary Road, Bangalore 560065, India.
authors.forename: Sonia
authors.initials: S
authors.lastname: Sen
authors.affiliation: National Centre for Biological Sciences - Tata Institute of Fundamental Research, UAS-GKVK Campus, Bellary Road, Bangalore 560065, India Present address: FIRC Institute of Molecular Oncology, Via Adamello, 16-20139 Milan, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Biagini
authors.affiliation: Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Reichert
authors.affiliation: National Centre for Biological Sciences - Tata Institute of Fundamental Research, UAS-GKVK Campus, Bellary Road, Bangalore 560065, India vijay@ncbs.res.in.
authors.forename: K
authors.initials: K
authors.lastname: VijayRaghavan
keywords: Drosophila; Neuroblast; Olfactory interneuron; Otd