Articles by Stephen Janoschka in JoVE
Studying the Integration of Adult-born Neurons Yan Gu1, Stephen Janoschka1, Shaoyu Ge1 1Department of Neurobiology & Behavior, State University of New York at Stony Brook A way to study the integration of newborn dentate granule cells in adult animals is described. This technique uses an engineered retrovirus to label newborn neurons, followed by electrophysiological recordings to determine in vivo functional integration.
Other articles by Stephen Janoschka on PubMed
Early Involvement of Synapsin III in Neural Progenitor Cell Development in the Adult Hippocampus The Journal of Comparative Neurology. Apr, 2008 | Pubmed ID: 18271024 Synapsin III is a synaptic vesicle-associated protein that is expressed in cells of the subgranular layer of the hippocampal dentate gyrus, a brain region known to sustain substantial levels of neurogenesis into adulthood. Here we tested the hypothesis that synapsin III plays a role in adult neurogenesis with synapsin III knockout and wild-type mice. Immunocytochemistry of the adult hippocampal dentate gyrus revealed that synapsin III colocalizes with markers of neural progenitor cell development (nestin, PSA-NCAM, NeuN, and Tuj1) but did not colocalize with markers of mitosis (Ki67 and PCNA). Because neurogenesis consists of a number of stages, the proliferation, survival, and differentiation of neural progenitor cells were systematically quantitated in the hippocampal dentate gyrus of adult synapsin III knockout and wild-type mice. We found a 30% decrease in proliferation and a 55% increase in survival of neural progenitor cells in synapsin III knockout mice. We also observed a 6% increase in the number of neural progenitor cells that differentiated into neurons. No difference in the volume of the dentate gyrus was observed between synapsin III knockout and wild-type mice. Collectively, our results demonstrate a novel role for synapsin III in regulating the proliferation of neural progenitor cells in the adult hippocampal dentate gyrus. These findings suggest a distinct function for this synaptic vesicle protein, in addition to its role in neurotransmission.
Patterns of Fluorescent Protein Expression in Scleractinian Corals The Biological Bulletin. Oct, 2008 | Pubmed ID: 18840775 Biofluorescence exists in only a few classes of organisms, with Anthozoa possessing the majority of species known to express fluorescent proteins. Most species within the Anthozoan subgroup Scleractinia (reef-building corals) not only express green fluorescent proteins, they also localize the proteins in distinct anatomical patterns.We examined the distribution of biofluorescence in 33 coral species, representing 8 families, from study sites on Australia's Great Barrier Reef. For 28 of these species, we report the presence of biofluorescence for the first time. The dominant fluorescent emissions observed were green (480-520 nm) and red (580-600 nm). Fluorescent proteins were expressed in three distinct patterns (highlighted, uniform, and complementary) among specific anatomical structures of corals across a variety of families. We report no significant overlap between the distribution of fluorescent proteins and the distribution of zooxanthellae. Analysis of the patterns of fluorescent protein distribution provides evidence that the scheme in which fluorescent proteins are distributed among the anatomical structures of corals is nonrandom. This targeted expression of fluorescent proteins in corals produces contrast and may function as a signaling mechanism to organisms with sensitivity to specific wavelengths of light.
A Role for Primary Cilia in Glutamatergic Synaptic Integration of Adult-born Neurons Nature Neuroscience. Feb, 2012 | Pubmed ID: 22306608 The sequential synaptic integration of adult-born neurons has been widely examined in rodents, but the mechanisms regulating the integration remain largely unknown. The primary cilium, a microtubule-based signaling center, is essential for vertebrate development, including the development of the CNS. We examined the assembly and function of the primary cilium in the synaptic integration of adult-born mouse hippocampal neurons. Primary cilia were absent in young adult-born neurons, but assembled precisely at the stage when newborn neurons approach their final destination, further extend dendrites and form synapses with entorhinal cortical projections. Conditional deletion of cilia from adult-born neurons induced severe defects in dendritic refinement and synapse formation. Deletion of primary cilia led to enhanced Wnt and Î²-catenin signaling, which may account for these developmental defects. Taken together, our findings identify the assembly of primary cilia as a critical regulatory event in the dendritic refinement and synaptic integration of adult-born neurons.