Angelika Stollewerk

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To uncover similarities and differences in neurogenesis in arthropod groups, we have studied the ventral neuroectoderm of the spider Cupiennius salei (Chelicerata, Aranea, Ctenidae). We found that invaginating cell groups arose sequentially, at stereotyped positions in each hemisegment and in separate waves, comparable with the generation of neuroblasts in(More)
It is currently debated whether segmentation in different animal phyla has a common origin and shares a common genetic mechanism. The apparent use of different genetic networks in arthropods and vertebrates has become a strong argument against a common origin of segmentation. Our knowledge of arthropod segmentation is based mainly on the insect Drosophila,(More)
The Drosophila gene pointed (pnt) encodes two putative transcription factors (P1 and P2) of the Ets family, which in the embryonic CNS are found exclusively in glial cells. Loss of pnt function leads to poorly differentiated glial cells and a marked decrease in the expression of the neuronal antigen 22C10 in the MP2 neurons, which are known to interact(More)
In Drosophila, glial cell development depends on the gene glial cells missing (gcm). gcm activates the expression of other transcription factors such as pointed and repo, which control subsequent glial differentiation. In order to better understand glial cell differentiation, we have screened for genes whose expression in glial cells depends on the activity(More)
Molecular data suggest that myriapods are a basal arthropod group and may even be the sister group of chelicerates. To find morphological indications for this relationship we have analysed neurogenesis in the myriapod Glomeris marginata (Diplopoda). We show here that groups of neural precursors, rather than single cells as in insects, invaginate from the(More)
Two classes of glial cells are found in the embryonic Drosophila CNS, midline glial cells and lateral glial cells. Midline glial development is triggered by EGF-receptor signalling, whereas lateral glial development is controlled by the gcm gene. Subsequent glial cell differentiation depends partly on the pointed gene. Here we describe a novel component(More)
Ten years ago we showed for the first time that Notch signalling is required in segmentation in spiders, indicating the existence of similar mechanisms in arthropod and vertebrate segmentation. However, conflicting results in various arthropod groups hampered our understanding of the ancestral function of Notch in arthropod segmentation. Here we fill a(More)
Despite differences in the formation of neural precursors, all arthropod species analyzed so far generate about 30 single precursors (insects/crustaceans) or precursor groups (chelicerates/myriapods) per hemi-segment. In Drosophila, each precursor has a distinct identity conferred by segment polarity and dorso-ventral patterning genes that subdivide the(More)
Similarly to vertebrates, arthropod brains are compartmentalized into centers with specific neurological functions such as cognition, behavior, and memory. The centers can be further subdivided into smaller functional units. This raises the question of how these compartments are formed during development and how they are integrated into brain centers. We(More)
In a recent comparative study on neurogenesis in the diplopod Glomeris marginata we have shown that the millipede and the spider share several features that cannot be found in homologous form in insects and crustaceans. The most distinctive difference is that groups of neural precursors are singled out from the neuroectoderm of the spider and the diplopod,(More)