Publications by authors named "Benjamin Altenhein"

Understanding how injury to the central nervous system induces de novo neurogenesis in animals would help promote regeneration in humans. Regenerative neurogenesis could originate from glia and glial neuron-glia antigen-2 (NG2) may sense injury-induced neuronal signals, but these are unknown. Here, we used to search for genes functionally related to the homologue and identified required in neurons for insulin secretion.

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During development, tissue growth is mediated by either cell proliferation or cell growth, coupled with polyploidy. Both strategies are employed by the cell types that make up the blood-brain barrier. During larval growth, the perineurial glia proliferate, whereas the subperineurial glia expand enormously and become polyploid.

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The biogenic amines octopamine (OA) and tyramine (TA) modulate insect motor behavior in an antagonistic manner. OA generally enhances locomotor behaviors such as larval crawling and flight, whereas TA decreases locomotor activity. However, the mechanisms and cellular targets of TA modulation of locomotor activity are incompletely understood.

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is a widely used genetic model organism in developmental biology. While this model organism has been intensively studied at the RNA level, a comprehensive proteomic study covering the complete life cycle is still missing. Here, we apply label-free quantitative proteomics to explore proteome remodeling across 's life cycle, resulting in 7952 proteins, and provide a high temporal-resolved embryogenesis proteome of 5458 proteins.

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Throughout evolution, glia have key regulatory roles in neural development and function. Typically, they control the response to developmental and/or pathological signals, thereby affecting neural proliferation, remodeling, survival, and regeneration. Such complex biology depends on the plastic features of glial cells, but also on the presence of different classes of glial cells, hence the importance of understanding the cellular and the molecular mechanisms underlying their development.

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Development and general organization of the nervous system is comparable between insects and vertebrates. Our current knowledge on the formation of neurogenic anlagen and the generation of neural stem cells is deeply influenced by work done in invertebrate model organisms such as Drosophila and Caenorhabditis elegans. It is the aim of this review to summarize the most important steps in neurogenesis in the Drosophila embryo with a special emphasis on glial cell progenitors and the specification of glial cells.

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In the article "Predetermined embryonic glial cells form the distinct glial sheaths of the Drosophila peripheral nervous system" we combined our expertise to identify glial cells of the embryonic peripheral nervous system on a single cell resolution with the possibility to genetically label cells using Flybow. We show that all 12 embryonic peripheral glial cells (ePG) per abdominal hemisegment persist into larval (and even adult) stages and differentially contribute to the three distinct glial layers surrounding peripheral nerves. Repetitive labelings of the same cell further revealed that layer affiliation, morphological expansion, and control of proliferation are predetermined and subject to an intrinsic differentiation program.

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During development, differentiation is often initiated by the activation of different receptor tyrosine kinases (RTKs), which results in the tightly regulated activation of cytoplasmic signaling cascades. In the differentiation of neurons and glia in the developing Drosophila eye, we found that the proper intensity of RTK signaling downstream of fibroblast growth factor receptor (FGFR) or epidermal growth factor receptor required two mutually antagonistic feedback loops. We identified a positive feedback loop mediated by the Ras association (RA) domain-containing protein Rau that sustained Ras activity and counteracted the negative feedback loop mediated by Sprouty.

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One of the numerous functions of glial cells in Drosophila is the ensheathment of neurons to isolate them from the potassium-rich haemolymph, thereby establishing the blood-brain barrier. Peripheral nerves of flies are surrounded by three distinct glial cell types. Although all embryonic peripheral glia (ePG) have been identified on a single-cell level, their contribution to the three glial sheaths is not known.

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Oligodendroglial Myelin Basic Protein (MBP) synthesis is essential for myelin formation in the central nervous system. During oligodendrocyte differentiation, MBP mRNA is kept in a translationally silenced state while intracellularly transported, until neuron-derived signals initiate localized MBP translation. Here we identify the small non-coding RNA 715 (sncRNA715) as an inhibitor of MBP translation.

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Here we report on the generation and in vivo analysis of a series of loss-of-function mutants for the Drosophila ArfGEF, Gartenzwerg. The Drosophila gene gartenzwerg (garz) encodes the orthologue of mammalian GBF1. garz is expressed ubiquitously in embryos with substantially higher abundance in cells forming diverse tubular structures such as salivary glands, trachea, proventriculus or hindgut.

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Transport of liquids or gases in biological tubes is fundamental for many physiological processes. Our knowledge on how tubular organs are formed during organogenesis and tissue remodeling has increased dramatically during the last decade. Studies on different animal systems have helped to unravel some of the molecular mechanisms underlying tubulogenesis.

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Development of the nervous system and establishment of complex neuronal networks require the concerted activity of different signalling events and guidance cues, which include Netrins and their receptors. In Drosophila, two Netrins are expressed during embryogenesis by cells of the ventral midline and serve as attractant or repellent cues for navigating axons. We asked whether glial cells, which are also motile, are guided by similar cues to axons, and analysed the influence of Netrins and their receptors on glial cell migration during embryonic development.

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In the Drosophila embryonic CNS several subtypes of glial cells develop, which arrange themselves at characteristic positions and presumably fulfil specific functions. The mechanisms leading to the specification and differentiation of glial subtypes are largely unknown. By DiI labelling in glia-specific Gal4 lines we have clarified the lineages of the lateral glia in the embryonic ventral nerve cord and linked each glial cell to a specific stem cell.

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Glial cells are crucial for the proper development and function of the nervous system. In the Drosophila embryo, the glial cells of the peripheral nervous system are generated both by central neuroblasts and sensory organ precursors. Most peripheral glial cells need to migrate along axonal projections of motor and sensory neurons to reach their final positions in the periphery.

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A prominent feature of glial cells is their ability to migrate along axons to finally wrap and insulate them. In the embryonic Drosophila PNS, most glial cells are born in the CNS and have to migrate to reach their final destinations. To understand how migration of the peripheral glia is regulated, we have conducted a genetic screen looking for mutants that disrupt the normal glial pattern.

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In the central nervous system of Drosophila, the induction of the glial cell fate is dependent on the transcription factor glial cells missing (gcm). Though a considerable number of other genes have been shown to be expressed in all or in subsets of glial cells, the course of glial cell differentiation and subtype specification is only poorly understood. This prompted us to design a whole genome microarray approach comparing gcm gain-of-function and, for the first time, gcm loss-of-function genetics to wildtype in time course experiments along embryogenesis.

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The analysis of mutants is an indispensable approach towards characterizing gene function. Combining several tools of Drosophila genetics, we designed a new strategy for a mutagenesis screen which is fast, easy-to-apply, and cheap. The combination of a cell-specific Gal4 line with an upstream activating sequence-green fluorescent protein (UAS-GFP) allows the in vivo detection of the cells or tissues of interest without the need for fixation and staining.

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Locomotion relies on stable attachment of muscle fibres to their target sites, a process that allows for muscle contraction to generate movement. Here, we show that glide/gcm and glide2/gcm2, the fly glial cell determinants, are expressed in a subpopulation of embryonic tendon cells and required for their terminal differentiation. By using loss-of-function approaches, we show that in the absence of both genes, muscle attachment to tendon cells is altered, even though the molecular cascade induced by stripe, the tendon cell determinant, is normal.

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We have cloned and sequenced cDNAs coding for the complete primary structure of HtH2, the second hemocyanin isoform of the marine gastropod Haliotis tuberculata. The deduced protein sequence comprises 3399 amino acids, corresponding to a molecular mass of 392 kDa. It shares only 66% of structural identity with the previously analysed first isoform HtH1, and according to a molecular clock, the two isoforms of Haliotis hemocyanin separated ca.

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