TY  - JOUR
A1  - Schmitt, Dominique
A1  - Funk, Natalia
A1  - Blum, Robert
A1  - Asan, Esther
A1  - Andersen, Lill
A1  - Rülicke, Thomas
A1  - Sendtner, Michael
A1  - Buchner, Erich
T1  - Initial characterization of a Syap1 knock-out mouse and distribution of Syap1 in mouse brain and cultured motoneurons
JF  - Histochemistry and Cell Biology
N2  - Synapse-associated protein 1 (Syap1/BSTA) is the mammalian homologue of Sap47 (synapse-associated protein of 47 kDa) in Drosophila. Sap47 null mutant larvae show reduced short-term synaptic plasticity and a defect in associative behavioral plasticity. In cultured adipocytes, Syap1 functions as part of a complex that phosphorylates protein kinase B alpha/Akt1 (Akt1) at Ser\(^{473}\) and promotes differentiation. The role of Syap1 in the vertebrate nervous system is unknown. Here, we generated a Syap1 knock-out mouse and show that lack of Syap1 is compatible with viability and fertility. Adult knock-out mice show no overt defects in brain morphology. In wild-type brain, Syap1 is found widely distributed in synaptic neuropil, notably in regions rich in glutamatergic synapses, but also in perinuclear structures associated with the Golgi apparatus of specific groups of neuronal cell bodies. In cultured motoneurons, Syap1 is located in axons and growth cones and is enriched in a perinuclear region partially overlapping with Golgi markers. We studied in detail the influence of Syap1 knockdown and knockout on structure and development of these cells. Importantly, Syap1 knockout does not affect motoneuron survival or axon growth. Unexpectedly, neither knockdown nor knockout of Syap1 in cultured motoneurons is associated with reduced Ser\(^{473}\) or Thr\(^{308}\) phosphorylation of Akt. Our findings demonstrate a widespread expression of Syap1 in the mouse central nervous system with regionally specific distribution patterns as illustrated in particular for olfactory bulb, hippocampus, and cerebellum.
KW  - Protein kinase B
KW  - Spinal Muscular-arthropy
KW  - Rictor-mTOR complex
KW  - Neurotrophic factors
KW  - Plasma-membrane
KW  - Axon growth
KW  - SAP47 gene
KW  - Phosphorylation
KW  - Drosophilia
KW  - Cells
KW  - BSTA
KW  - Viability
KW  - Brain
KW  - Syap1 localization
KW  - Glutamatergic synapses
KW  - PKB/Akt phosphorylation
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187258
VL  - 146
IS  - 4
ER  - 
TY  - JOUR
A1  - Rybalka, Nataliya
A1  - Wolf, Matthias
A1  - Andersen, Robert
A1  - Friedl, Thomas
T1  - Congruence of chloroplast- and nuclear-encoded DNA sequence variations used to assess species boundaries in the soil microalga Heterococcus (Stramenopiles, Xanthophyceae)
JF  - BMC Evolutionary Biology
N2  - Background: Heterococcus is a microalgal genus of Xanthophyceae (Stramenopiles) that is common and widespread in soils, especially from cold regions. Species are characterized by extensively branched filaments produced when grown on agarized culture medium. Despite the large number of species described exclusively using light microscopic morphology, the assessment of species diversity is hampered by extensive morphological plasticity. 
Results: Two independent types of molecular data, the chloroplast-encoded psbA/rbcL spacer complemented by rbcL gene and the internal transcribed spacer 2 of the nuclear rDNA cistron (ITS2), congruently recovered a robust phylogenetic structure. With ITS2 considerable sequence and secondary structure divergence existed among the eight species, but a combined sequence and secondary structure phylogenetic analysis confined to helix II of ITS2 corroborated relationships as inferred from the rbcL gene phylogeny. Intra-genomic divergence of ITS2 sequences was revealed in many strains. The 'monophyletic species concept', appropriate for microalgae without known sexual reproduction, revealed eight different species. Species boundaries established using the molecular-based monophyletic species concept were more conservative than the traditional morphological species concept. Within a species, almost identical chloroplast marker sequences (genotypes) were repeatedly recovered from strains of different origins. At least two species had widespread geographical distributions; however, within a given species, genotypes recovered from Antarctic strains were distinct from those in temperate habitats. Furthermore, the sequence diversity may correspond to adaptation to different types of habitats or climates. 
Conclusions: We established a method and a reference data base for the unambiguous identification of species of the common soil microalgal genus Heterococcus which uses DNA sequence variation in markers from plastid and nuclear genomes. The molecular data were more reliable and more conservative than morphological data.
KW  - xanthophyceae
KW  - psbA/rbcL spacer
KW  - ITS2
KW  - tool
KW  - RBCL
KW  - alignment
KW  - evolution
KW  - chlorophyta
KW  - RNA secondary structure
KW  - terrestrial habitats
KW  - phylogenetic trees
KW  - mixed models
KW  - green algae
KW  - heterococcus
KW  - systematics
KW  - molecular phylogeny
KW  - species concept
Y1  - 2013
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121848
SN  - 1471-2148
VL  - 13
IS  - 39
ER  -