- Email: [email protected]
Expression of chondroitin sulfate sulfotransferases in the developing mouse cerebellum
S88
Abstracts / Neuroscience Research 58S (2007) S1–S244
Expression of chondroitin sulfate sulfotransferases in P1-d20
P1-d24 Roles of pre- and post-synaptic neuron activity in inter-
the developing mouse cerebellum
hemispheric connection development in the mouse visual cortex
Maki Ishii, Nobuaki Maeda Department of Developmental Neuroscience, Tokyo Metropolitan Institute for Neuroscience, Tokyo, Japan
1
Chondroitin sulfate (CS) chains are modified by various sulfotransferases generating diverse sulfation patterns, which are assumed to be involved in the selective binding to various proteins, such as growth factors. Our previous study suggested that CS-D type structure generated by UST is important for the development of Purkinje cells. In this study, we analyzed the expression patterns of several CS sulfotransferases (UST, GalNAc46ST, D4ST) in the postnatal mouse cerebellum. While the expression of UST gene increased from P1 to P14, that of GalNAc4S-6ST and D4ST genes decreased during this period. Using in situ hybridization, it was revealed that these genes were expressed by Purkinje cells, Bergmann glia, and granular cells. These results suggest that the structural variation of CS chains may regulate Purkinje cell-Bergmann glia interaction and granule cell migration.
P1-d21 The role of sonic hedgehog in dendritic spine formation Nobunari Sasaki, Junko Kurisu, Mineko Kengaku Laboratory for Neural Cell Polarity, RIKEN Brain Science Institute, Saitama, Japan During development of vertebrate central nervous system (CNS), Sonic hedgehog plays essential roles in various processes including dorsoventral patterning of the neural tube, proliferation of neural progenitors and guidance of growing axons. Here, we found that Sonic hedgehog induced dendritic spine formation in primary cultured neurons. Sonic hedgehog and its receptors Patched1 and smoothened were expressed in developing cerebellar Purkinje neurons and hippocampal pyramidal neurons at early postnatal stages. Sonic hedgehog treatment significantly enhanced spine maturation in hippocampal neurons. Conversely, inhibition of Sonic hedgehog pathway by a specific inhibitor cyclopamine retarded spine maturation. GST-pull down assays revealed that smoothened bound to molecules localized at post-synaptic density via the cytoplasmic tail, suggesting its localization in the post-synaptic membrane. These data suggest that Sonic hedgehog might be involved in spine formation in CNS dendrites.
P1-d22 Essential role of Rac1 in development of cerebral cortex and hippocampus Hidetoshi Kassai 1 , Toshio Terashima 2 , Masahiro Fukaya 3 , Eriko Miura 3 , Masahiko Watanabe 3 , Atsu Aiba 1 1 Division of Molecular Genet., Kobe University Graduate School of Medicine, Kobe, Japan; 2 Division of Anat. Neurobiol., Kobe University Graduate School of Medicine, Kobe, Japan; 3 Department Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan Neuronal development requires highly precise regulation of actin-based structures to achieve coordinated migration and precise wiring of neurons. Rac1, a member of the Rho family of small GTPases, is assumed to regulate neuronal cell migration and neurite outgrowth through actin cytoskeletal reorganization. However, it is poorly understood how Rac1 contributes to these cellular functions because of the embryonic lethality of Rac1-deficient mice. In this study, we show that conditional deletion of Rac1 in the dorsal telencephalon, including cerebral cortex, hippocampus and olfactory bulb, results in abnormal cortical and hippocampal morphogenesis. The mutant mice showed partially abnormal layering of cerebral cortex and striking reduction of commissural axons, such as the corpus callosum and the anterior commissure. These results suggest that Rac1 requires neuronal cell migration and proper axonal targeting in cerebral cortex.
Hidenobu Mizuno 1,2 , Tomoo Hirano 1,2 , Yoshiaki Tagawa 1,2 Department of Biophysics, Kyoto University Graduate School of Science, Kyoto, Japan; 2 CREST, JST, Kawaguchi, Japan Targeted neuronal silencing using ion channels becomes a useful technique to elucidate the mechanism for activity-dependent neuronal wiring. By using a potassium channel Kir2.1, we investigated the role of neuronal activity in the formation of interhemispheric (callosal) axon projections. The region- and layer-specific projection pattern of callosal axons from one cortical hemisphere to the other was visualized by unilateral in vivo GFP electroporation. To explore the role of neuronal activity in callosal axon development, Kir2.1 was expressed in either callosal projection neurons or their target postsynaptic neurons. Exogenous Kir2.1 expression in cortical neurons reduced their firing rate. Kir2.1 expression in projection neurons disturbed their axon arbor growth, while that in postsynaptic neurons had limited effect on the pattern of pre-synaptic axon projections. These results suggest that targeted Kir2.1 expression is a useful method to reveal distinct effects of pre- and post-synaptic activity-blockade on cortical wiring.
P1-d25 ARD1-NAT1 complex regulates neuronal dendritic arborization through ␣-tubulin acetylation
Noriaki Ohkawa 1 , Shunichiro Sugisaki 1,2 , Eri Tokunaga 1 , Kazuko Fujitani 1 , Mitsutoshi Setou 1 , Kaoru Inokuchi 1,2,3 1 Mitsubishi Kagaku Institute of Life Science (MITILS), Tokyo, Japan; 2 Yokohama National University, Yokohama, Japan; 3 CREST, JST, Kawaguchi, Japan A regulation of microtubule (MT) organization is critical for the dendritic development. Expression of ARD1 and NAT1, an N-acetyltransferase complex, increased during dendritic development, and both proteins were co-localized with MT in dendrites. We investigated whether the complex functions on dendritic development through ␣-tubulin acetylation. Alpha-tubulin acetylation at Lys40 was critical to the dendritic extension. ARD1-NAT1 complex enhanced a transfer of acetyl group to purified MT fraction. ARD1 is a catalytic subunit of the N-acetyltransferase, and knockdown of the ARD1 reduced the acetylation level of ␣-tubulin in HEK293T and dendritic extension in cultured neurons. Overexpression of dominantnegative form of ARD1 also limited the dendritic arborization. We propose that the regulation of ␣-tubulin acetylation by ARD1-NAT1 pathway is involved in the dendritic development. Special Coordinate Funds for Promoting Science and Technology of the Japanese Government.
P1-d26 Involvement of BIG-2 in convergence of olfactory axons to target glomeruli Tomomi Kaneko-Goto 1 , Sei-Ichi Yoshihara 1 , Yoshihiro Yoshihara 1,2 1 RIKEN BSI, Wako-shi, Japan; 2 CREST, JST, Osaka, Japan Olfactory sensory neurons (OSNs) expressing a given odorant receptor (OR) converge their axons onto a few topographically fixed glomeruli, resulting in establishment of the odor map on the olfactory bulb (OB). Here we report that BIG-2 (contactin 4), a GPI-anchored axonal glycoprotein belonging to the immunoglobulin superfamily, is expressed by a subpopulation of OSNs. Immunohistochemical staining of mouse OB sections revealed a mosaic pattern of glomerular arrangement with strongly BIG-2-positive, weakly positive, and negative axon terminals, which is overlapping but different from mosaic expression patterns of Kirrel2 and ephrin-A5. There is a close correlation between the expression level of BIG-2 protein and the choice of OR in individual OSNs. In BIG-2-deficient mice, OSNs expressing a given OR frequently innervate multiple glomeruli at ectopic locations. These results suggest that BIG-2 is one of the axon guidance molecules playing crucial roles in the formation and maintenance of functional odor map in the OB. Research fund: KAKENHI 16300105
Abstracts / Neuroscience Research 58S (2007) S1–S244
Expression of chondroitin sulfate sulfotransferases in P1-d20
P1-d24 Roles of pre- and post-synaptic neuron activity in inter-
the developing mouse cerebellum
hemispheric connection development in the mouse visual cortex
Maki Ishii, Nobuaki Maeda Department of Developmental Neuroscience, Tokyo Metropolitan Institute for Neuroscience, Tokyo, Japan
1
Chondroitin sulfate (CS) chains are modified by various sulfotransferases generating diverse sulfation patterns, which are assumed to be involved in the selective binding to various proteins, such as growth factors. Our previous study suggested that CS-D type structure generated by UST is important for the development of Purkinje cells. In this study, we analyzed the expression patterns of several CS sulfotransferases (UST, GalNAc46ST, D4ST) in the postnatal mouse cerebellum. While the expression of UST gene increased from P1 to P14, that of GalNAc4S-6ST and D4ST genes decreased during this period. Using in situ hybridization, it was revealed that these genes were expressed by Purkinje cells, Bergmann glia, and granular cells. These results suggest that the structural variation of CS chains may regulate Purkinje cell-Bergmann glia interaction and granule cell migration.
P1-d21 The role of sonic hedgehog in dendritic spine formation Nobunari Sasaki, Junko Kurisu, Mineko Kengaku Laboratory for Neural Cell Polarity, RIKEN Brain Science Institute, Saitama, Japan During development of vertebrate central nervous system (CNS), Sonic hedgehog plays essential roles in various processes including dorsoventral patterning of the neural tube, proliferation of neural progenitors and guidance of growing axons. Here, we found that Sonic hedgehog induced dendritic spine formation in primary cultured neurons. Sonic hedgehog and its receptors Patched1 and smoothened were expressed in developing cerebellar Purkinje neurons and hippocampal pyramidal neurons at early postnatal stages. Sonic hedgehog treatment significantly enhanced spine maturation in hippocampal neurons. Conversely, inhibition of Sonic hedgehog pathway by a specific inhibitor cyclopamine retarded spine maturation. GST-pull down assays revealed that smoothened bound to molecules localized at post-synaptic density via the cytoplasmic tail, suggesting its localization in the post-synaptic membrane. These data suggest that Sonic hedgehog might be involved in spine formation in CNS dendrites.
P1-d22 Essential role of Rac1 in development of cerebral cortex and hippocampus Hidetoshi Kassai 1 , Toshio Terashima 2 , Masahiro Fukaya 3 , Eriko Miura 3 , Masahiko Watanabe 3 , Atsu Aiba 1 1 Division of Molecular Genet., Kobe University Graduate School of Medicine, Kobe, Japan; 2 Division of Anat. Neurobiol., Kobe University Graduate School of Medicine, Kobe, Japan; 3 Department Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan Neuronal development requires highly precise regulation of actin-based structures to achieve coordinated migration and precise wiring of neurons. Rac1, a member of the Rho family of small GTPases, is assumed to regulate neuronal cell migration and neurite outgrowth through actin cytoskeletal reorganization. However, it is poorly understood how Rac1 contributes to these cellular functions because of the embryonic lethality of Rac1-deficient mice. In this study, we show that conditional deletion of Rac1 in the dorsal telencephalon, including cerebral cortex, hippocampus and olfactory bulb, results in abnormal cortical and hippocampal morphogenesis. The mutant mice showed partially abnormal layering of cerebral cortex and striking reduction of commissural axons, such as the corpus callosum and the anterior commissure. These results suggest that Rac1 requires neuronal cell migration and proper axonal targeting in cerebral cortex.
Hidenobu Mizuno 1,2 , Tomoo Hirano 1,2 , Yoshiaki Tagawa 1,2 Department of Biophysics, Kyoto University Graduate School of Science, Kyoto, Japan; 2 CREST, JST, Kawaguchi, Japan Targeted neuronal silencing using ion channels becomes a useful technique to elucidate the mechanism for activity-dependent neuronal wiring. By using a potassium channel Kir2.1, we investigated the role of neuronal activity in the formation of interhemispheric (callosal) axon projections. The region- and layer-specific projection pattern of callosal axons from one cortical hemisphere to the other was visualized by unilateral in vivo GFP electroporation. To explore the role of neuronal activity in callosal axon development, Kir2.1 was expressed in either callosal projection neurons or their target postsynaptic neurons. Exogenous Kir2.1 expression in cortical neurons reduced their firing rate. Kir2.1 expression in projection neurons disturbed their axon arbor growth, while that in postsynaptic neurons had limited effect on the pattern of pre-synaptic axon projections. These results suggest that targeted Kir2.1 expression is a useful method to reveal distinct effects of pre- and post-synaptic activity-blockade on cortical wiring.
P1-d25 ARD1-NAT1 complex regulates neuronal dendritic arborization through ␣-tubulin acetylation
Noriaki Ohkawa 1 , Shunichiro Sugisaki 1,2 , Eri Tokunaga 1 , Kazuko Fujitani 1 , Mitsutoshi Setou 1 , Kaoru Inokuchi 1,2,3 1 Mitsubishi Kagaku Institute of Life Science (MITILS), Tokyo, Japan; 2 Yokohama National University, Yokohama, Japan; 3 CREST, JST, Kawaguchi, Japan A regulation of microtubule (MT) organization is critical for the dendritic development. Expression of ARD1 and NAT1, an N-acetyltransferase complex, increased during dendritic development, and both proteins were co-localized with MT in dendrites. We investigated whether the complex functions on dendritic development through ␣-tubulin acetylation. Alpha-tubulin acetylation at Lys40 was critical to the dendritic extension. ARD1-NAT1 complex enhanced a transfer of acetyl group to purified MT fraction. ARD1 is a catalytic subunit of the N-acetyltransferase, and knockdown of the ARD1 reduced the acetylation level of ␣-tubulin in HEK293T and dendritic extension in cultured neurons. Overexpression of dominantnegative form of ARD1 also limited the dendritic arborization. We propose that the regulation of ␣-tubulin acetylation by ARD1-NAT1 pathway is involved in the dendritic development. Special Coordinate Funds for Promoting Science and Technology of the Japanese Government.
P1-d26 Involvement of BIG-2 in convergence of olfactory axons to target glomeruli Tomomi Kaneko-Goto 1 , Sei-Ichi Yoshihara 1 , Yoshihiro Yoshihara 1,2 1 RIKEN BSI, Wako-shi, Japan; 2 CREST, JST, Osaka, Japan Olfactory sensory neurons (OSNs) expressing a given odorant receptor (OR) converge their axons onto a few topographically fixed glomeruli, resulting in establishment of the odor map on the olfactory bulb (OB). Here we report that BIG-2 (contactin 4), a GPI-anchored axonal glycoprotein belonging to the immunoglobulin superfamily, is expressed by a subpopulation of OSNs. Immunohistochemical staining of mouse OB sections revealed a mosaic pattern of glomerular arrangement with strongly BIG-2-positive, weakly positive, and negative axon terminals, which is overlapping but different from mosaic expression patterns of Kirrel2 and ephrin-A5. There is a close correlation between the expression level of BIG-2 protein and the choice of OR in individual OSNs. In BIG-2-deficient mice, OSNs expressing a given OR frequently innervate multiple glomeruli at ectopic locations. These results suggest that BIG-2 is one of the axon guidance molecules playing crucial roles in the formation and maintenance of functional odor map in the OB. Research fund: KAKENHI 16300105