pueblo del maiz

Abstracts / Neuroscience Research 58S (2007) S1–S244

P3-d27 Regulatory mechanisms of Cdh6 gene expression in the postnatal mouse brain Takayoshi Inoue, Yukiko Inoue, Junko Asami, Hitomi Izumi, Shun Nakamura National Institute of Neuroscience, Tokyo, Japan Cdh6 is a synaptic adhesion molecule whose expression demarcates neural circuits such as auditory, somatosensory and other systems in the postnatal mouse brain. While crucial roles of cadherins in formation and/or modulation of synaptic junction have been implicated, what brings cadherin expressions in restricted sets of neurons along functional circuitries remains largely unknown. Here we investigate genetic control elements that could confine Cdh6 expression within subsets of neurons by using an innovative method in which systematic integration of a reporter cassette into bacterial artificial chromosomes with extensive coverage of huge Cdh6 gene locus was followed by fine visualization of reporter activities in the postnatal mouse brain after the transgenesis. Our screening revealed that divisible genomic segments controlled each nucleus specific expression of Cdh6 at right timing for circuit formation, suggesting developmental and/or evolutional value of cadherin regulatory machineries to shape elaborated neuronal circuitries in the nervous system.

S205

 Expression of NEPH family of immunoglobulin superP3-d30 family in the hindbrain Kazuhiko Nishida 1 , Haruki Takeuchi 2 , Hitoshi Sakano 2 , Fujio Murakami 1 1 Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan; 2 Graduate School of Science, Tokyo University, Tokyo, Japan NEPH family molecules including NEPH1,2,3 and nephrin belong to the transmembrane immunoglobulin superfamily and are involved in cell adhesion in the kidney. Although their expression has been reported in the nervous system, their function remains unclear. In the present study, we analyzed the expression of NEPH family molecules in the hindbrain. Among NEPH family members, mRNA of NEPH3 and nephrin are strongly expressed in the ventricular zones of the dorsolateral pons and the cerebellum at E11.5, and their expression gradually decreases at later stages. NEPH3 and nephrin-positive cells are not Tuj1-positive, suggesting that they are not mature neurons. Within the ventricular zones, NEPH3 and nephrin cells are not localized in Math1 or Neurogenin1-positive area. We are currently analyzing the identity of NEPH3 and nephrin-positive cells, and the function of these molecules in the hindbrain. Research funds: KAKENHI

P3-d28 Localization of Protocadherin-␣ protein in the mouse hippocampal neuron Atsushi Okayama, Ryosuke Kaneko, Takeshi Yagi Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan The Protocadherin-␣ (Pcdh-␣) proteins, members of clustered protocadherin family, are putative cell recognition/adhesion molecules in the brain. Here, we examined localization of Pcdh-␣ proteins in hippocampal culture by using monoclonal antibody against Pcdh-␣ cytoplasmic region, and by time-lapse imaging of GFP fused Pcdh-␣ proteins. The double-label immunostaining using antibodies against Pcdh-␣, Pcdh-␥, synapsin-1 (presynapse), PSD95 (post-synapse), and ␥-adaptin (golgi apparatus) showed that the dotted signals of Pcdh-␣ were observed on growth cone, neurite and soma. Although no Pcdh-␣ was double-labelled with synapsin-1, PSD95 nor ␥-adaptin, most of Pcdh-␣ were colocalized with Pcdh-␥. Next, GFP fused Pcdh-␣ protein was transfected to mouse hippocampal culture. The fused proteins were detected on soma, neurite, and growth cone, similar to endogenous proteins. The time-lapse imaging revealed that the part of fused proteins moved along with neurites. Understanding of Pcdh␣ protein localization will contribute to uncover molecular mechanisms underlying neural circuit formation. Research funds: KAKENHI 17024034

P3-d31 Protocadherin-␣ family is required for sensorimotor gating and spatial learning Emi Fukuda 1 , Shun Hamada 2 , Takahiro Hirabayashi 1 , Takeshi Yagi 1 1 FBS, Osaka University, Suita, Japan; 2 Fukuoka Women’s University, Japan Protocadherin (Pcdh)-␣ family is a subfamily of the clustered protocadherin family that occurs as diverse splicing variants. Pcdha proteins are located in axons during the neurodevelopment and partially at the synapses. However the roles of the Pcdha function in the brain are not well understood. To address in vivo function of the Pcdha family, we generated several lines of Pcdha gene-targeted mice and subjected them to anatomical, biochemical and behavioral approaches. Among these mutant, Pcdha ∆Bneo/∆Bneo which lacked a splicing variant of Pcdha-B and downregulated Pcdha-A proteins to approximately 20% showed no obvious morphological abnormalities in the brain. They, however, displayed enhancement of contextual fear conditioning and also deficit in prepulse inhibition (PPI) of the acoustic startle response in behaviors. Moreover, the abnormality of PPI was often rescued by administration of haloperidol, which is dopamine D2 receptor antagonist. These results suggest that Pcdha family proteins involve in behavioral regulation for fear learning and sensorimotor processing. Research funds: KAKENHI 17024034

P3-d29 Lamina-specific expression and subcellular localization of protocadherin9 in the developing cortex Asuka Matsui, Mayu Yoshioka, Nobuhiko Yamamoto Frontier Bioscience, University of Osaka, Osaka, Japan During development, sensory thalamic axons form branches in layers 4 and 6. To explore the layer-specific targeting mechanism, we searched for the genes that are expressed in the target layers, by constructing a subtraction cDNA library. We found that protocadherin9 (pcdh9) was expressed specifically in layers 4 and 6 of P7 rat cortex. In terms of area specificity, pcdh9 was expressed strongly in the occipital region. In the developmental time course, pcdh9 was already expressed in the cortical plate at E18. The expression was gradually increased by P7 and thereafter decreased. Pcdh9 expressed in the thalamus as well, particularly in the lateral geniculate nucleus and ventral posteromedial nucleus. Furthermore, the expression analysis of pcdh9-EGFP in dissociated cell culture demonstrated that the protein was more localized in cell bodies, dendrites, and synaptic buttons of cortical neurons. These results suggest that pcdh9 may be involved in the interaction between thalamocortical axons and cortical neurons in the target layers. Research funds: KAKENHI(18021021)

P3-d32 Protocadherin-␣ family is required for early establishment and maintenance of the olfactory axonal projection Sonoko Hasegawa 1 , Shun Hamada 2 , You Kumode 1,3 , Takahiro Hirabayashi 1 , Peter Mombaerts 3 , Takeshi Yagi 1 1 FBS, Osaka University, Suita, Japan; 2 Fukuoka Women’s University, Fukuoka, Japan; 3 Rockefeller University, USA Olfactory sensory neurons (OSNs) expressing the same odorant receptor project precisely their axons to specific glomeruli in the olfactory bulb. This process is directed by axonal identity of odorant receptor and neural activity. However, other molecules must also contribute to the mechanisms underlying the appropriate olfactory sensory map formation. Here we demonstrate that protocadherin-␣ (Pcdha) proteins, diverse cadherin-related molecules that are encoded as a gene cluster, are highly concentrated in the axons of OSNs and olfactory glomeruli. Pcdha genetargeted mice, in which a conserved region of the Pcdha gene cluster is deleted, show disturbed OSN axonal sorting to the glomeruli, and small, ectopic glomeruli. Interestingly, the abnormal projections were observable in neonates and these ectopic glomeruli do not disappear with age. Thus, Pcdha molecules are involved in the early establishment and maintenance of OSN axonal sorting into specific glomeruli in the olfactory bulb. Research funds: KAKENHI (17024034)