Search results for "Hox"

Cyclin E acts under the control of Hox-genes as a cell fate determinant in the developing central nervous system.

2005

The mechanisms controlling the generation of cell diversity in the central nervous system belong to the major unsolved problems in developmental biology. The fly Drosophila melanogaster is a suitable model system to examine these mechanisms at the level of individually identifiable cells. Recently, we have provided evidence that CyclinE--largely independent of its role in cell proliferation--plays a critical role in the specification of neural stem cells (neuroblasts). CycE specifies neuronal fate within neuroblast lineages by acting upstream of glial factors (prospero and glial cell missing), whereby levels of CycE are controlled by homeotic genes, the master control genes regulating segme…

Abdominal-A mediated repression of Cyclin E expression during cell-fate specification in the Drosophila central nervous system

2009

Homeotic/Hox genes are known to specify a given developmental pathway by regulating the expression of downstream effector genes. During embryonic CNS development of Drosophila, the Hox protein Abdominal-A (AbdA) is required for the specification of the abdominal NB6-4 lineage. It does so by down regulating the expression of the cell cycle regulator gene Dcyclin E (CycE). CycE is normally expressed in the thoracic NB6-4 lineage to give rise to mixed lineage of neurons and glia, while only glial cells are produced from the abdominal NB6-4 lineage due to the repression of CycE by AbdA. Here we investigate how AbdA represses the expression of CycE to define the abdominal fate of a single NB6-4 …

Impact of Ultrabithorax alternative splicing on Drosophila embryonic nervous system development.

2015

Hox genes control divergent segment identities along the anteroposterior body axis of bilateral animals by regulating a large number of processes in a cell context-specific manner. How Hox proteins achieve this functional diversity is a long-standing question in developmental biology. In this study we investigate the role of alternative splicing in functional specificity of the Drosophila Hox gene Ultrabithorax (Ubx). We focus specifically on the embryonic central nervous system (CNS) and provide a description of temporal expression patterns of three major Ubx isoforms during development of this tissue. These analyses imply distinct functions for individual isoforms in different stages of n…

Multiple roles forHoxgenes in segment-specific shaping of CNS lineages

2008

In this article we highlight some of the recently accumulating evidence showing that Hox genes are involved at different steps during the development of neural cell lineages to control segmental patterning of the CNS. In addition to their well-known early role in establishing segmental identities, Hox genes act on neural stem cells and their progeny at various stages during embryonic and postembryonic development to control proliferation, cell fate and/or apoptosis in a segment-specific manner. This leads to differential shaping of serially homologous lineages and thus to structural diversification of segmental CNS units (neuromeres) in adaptation to their specific functional tasks in proce…

Composition of a Neuromere and Its Segmental Diversification under the Control ofHoxGenes in the Embryonic CNS ofDrosophila

2014

Studies performed at the level of single, identified cells in the fruitfly Drosophila have decisively contributed to our understanding of the mechanisms underlying the development and function of the nervous system. This review highlights some of the work based on single-cell analyses in the embryonic/larval CNS that sheds light on the principles underlying formation and organization of an entire segmental unit and its divergence along the anterior/posterior body axis.

Abdominal-B and caudal inhibit the formation of specific neuroblasts in the Drosophila tail region

2013

The central nervous system of Drosophila melanogaster consists of fused segmental units (neuromeres), each generated by a characteristic number of neural stem cells (neuroblasts). In the embryo, thoracic and anterior abdominal neuromeres are almost equally sized and formed by repetitive sets of neuroblasts, whereas the terminal abdominal neuromeres are generated by significantly smaller populations of progenitor cells. Here we investigated the role of the Hox gene Abdominal-B in shaping the terminal neuromeres. We show that the regulatory isoform of Abdominal-B (Abd-B.r) not only confers abdominal fate to specific neuroblasts (e.g. NB6-4) and regulates programmed cell death of several proge…

Segmental Organization of Cephalic Ganglia in Arthropods

2007

Cephalic ganglia in arthropods encompass neuromeres of the supraesophageal ganglion (i.e., the brain) and the subesophageal ganglion. Whereas neuromeres of the subesophageal ganglion are clearly distinguishable, the segmental pattern of the brain is derived and less well understood. In this article, we give an overview of the current state of a long-lasting debate on the segmental organization of the arthropod head and brain, discussing embryonic morphological and molecular data, with a main focus on insects. Embryonic expression data on key developmental genes such as engrailed, orthodenticle, and Hox genes will be summarized to compare the metameric organization of the head (sub- and supr…

The Orange Peel: An Outstanding Source of Chemical Resources

2021

Citrus sinensis (L.) Osbeck is a very common cultivar belonging to the Rutaceae family. It is largely diffused in several areas of the world characterized by mild to warm climate conditions. Its abundant worldwide production (up to 107 Tons. per year) and consumption both as the edible part of the fruit and as several types of derivative products imply the production of a huge amount of waste, such as the fruit pomace. Several ways of recycling this material have been developed in recent years: employment as fertilizer, fodder ingredient, and even cloth material. However, the chemical added value of Citrus sinensis peel has been underestimated despite the diversified and significant content…

o-Ethoxybenzamid-Mannichbasen als potentielle Prodrugs. o-Ethoxybenzamide Mannich Bases as Potential Prodrugs

1986

Inhibitory effects of N-acetylcysteine on the functional responses of human eosinophils in vitro

2007

Background Oxidative stress appears to be relevant in the pathogenesis of inflammation in allergic diseases like bronchial asthma. Eosinophils are oxidant-sensitive cells considered as key effectors in allergic inflammation. Objective The aim of this work was to study the effects of the clinically used antioxidant N-acetyl-L-cysteine (NAC) on the functional responses of human-isolated eosinophils. Methods Human eosinophils were purified from the blood of healthy donors by a magnetic bead separation system. The effects of NAC were investigated on the generation of reactive oxygen species (chemiluminescence and flow cytometry), Ca2+ signal (fluorimetry), intracellular glutathione (GSH; flow c…