Authors:	Myneni, Sudha Rani
Title:	Role of the anterior Hox genes in segment-specific NB7-3 lineage development in the embryonic central nervous system of Drosophila melanogaster
Online publication date:	10-Aug-2016
Year of first publication:	2016
Language:	english
Abstract:	The homeotic (Hox) genes specify the segmental identities along the anterior-posterior body axis. During Drosophila ventral nerve cord development, the Hox genes play a major role in many aspects of neurogenesis like neural cell fate specification, cell number, apoptosis and proper differentiation of the neurons at embryonic and post-embryonic development in a segmental manner. This study informed that Antennapedia complex (ANT-C) genes Deformed (Dfd), Sex combs reduced (Scr) and Antennapedia (Antp) control the number and size of NB7-3 lineages in a segment-specific manner. Analysis of NB7-3 lineages in these mutants shows a two-step Hox gene control at early and late embryonic phases of development. They exhibit prolonged survival of early dying neurons within this lineage until late developmental stages and importantly complete lineage duplication phenotype in a segment-specific way. Detailed study of the duplication phenotype in Antp mutants reveals that it arises from two sequentially delaminating neural stem cells (neuroblasts, NBs). In early Antp mutant embryos the neuroectodermal precursor (NEP) of NB7-3 performs an additional cell division before it attains neural identity. Both daughter cells subsequently delaminate as NB7-3 in a segment-specific manner due to prolonged proneural gene expression in the mutant. The study reveals that a Hox mediated simultaneous cell division and specification program can intersect in the neuroectoderm to control the number of delaminating neural stem cells. The Hox genes encode transcription factors that control the expression of downstream target genes through a common 60 amino acid domain, the homeodomain, which is involved in DNA-binding. The results in this study revealed that a combination of novel in vivo DNA-binding activity-dependent and -independent functions of ANT-C proteins are involved in regulating the neural stem cells arising from the NB7-3 proneural cluster. Regulation of cell division within the 7-3 NEP does not require the Hox DNA-binding function, but this function is necessary for prompt repression of proneural gene expression after NB delamination and, subsequently, for execution of proper apoptosis of NB7-3 progeny cells.
DDC:	570 Biowissenschaften 570 Life sciences
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 10 Biologie
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-4603
URN:	urn:nbn:de:hebis:77-diss-1000006065
Version:	Original work
Publication type:	Dissertation
License:	In Copyright
Information on rights of use:	https://rightsstatements.org/vocab/InC/1.0/
Extent:	129 Blätter
Appears in collections:	JGU-Publikationen