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246 Abstracts / Neuroscience R

ique in vitro. We further found the expression of CD74 in GE of E14 mouserain, suggesting the functional role of MIF in vivo. MIF increased the numberf primary and secondary neurospheres. In contrast, retrovirally expressedIF shRNAi suppressed the secondary neurosphere formations, cell prolif-

ration, and increased the caspase3/7 activity in neurospheres. Moreover,e found that in neurospheres MIF increases the phosphorylation of Akt,

rk, AMPK, and Stat3 (Ser727) which are known as factors supporting theell survival, proliferation and/or maintenance of NSPCs. Taken together,IF can cause proliferation and maintain NSPCs utilizing multiple-signaling

athways synergistically and may be a new therapeutic factor for brainegeneration disorders through NSPCs activation.eference

JNR. 2004; 76: 453-65

oi:10.1016/j.neures.2010.07.1088

2-d10 A novel function of Ca2+ in axon specification actinghrough the CaMKK/CaMKI pathwayhinichi Nakamuta 1 , Yasuhiro Funahashi 1,2, Takashi Namba 1,2,iroyuki kamiguchi 3, Kozo Kaibuchi 1,2

Graduate School of Medicine, Department of Cell Pharmacology, Nagoyanivers ity, Nagoya 2 CREST, JST, Tokyo 3 Laboratory for Neuronal Growthechanisms, RIKEN Brain Science Institute, Saitama

eurons are highly polarized cells that have axons and dendrites, bothf which are differentiated from common immature neurites in culturedippocampal neurons. Various extracellular and intracellular signals are

mplicated in axon specification. However, the causal relationship betweenhe intracellular signals and axon specification remains elusive, because liveell imaging of the signals during axon specification is difficult. We hereevelop a novel method, in which one of the immature neurites is selectivelyctivated by local application of neurotrophin-3 (NT-3). The stimulation ofhe selected neurite induces rapid Ca2+ increase at the neurite tip followedy neurite elongation in IP3-dependent fashion. Expression of constitutivelyctive forms of Ca2+ effectors such as CaMKK and its downstream kinase,aMKI, induce axon formation. Impairment of their functions prohibits axon

ormation in both cultured cells and cerebral cortex. These results reveal aovel role of Ca2+ in axon specification acting through the CaMKK/CaMKIathway.

oi:10.1016/j.neures.2010.07.1089

2-d11 Refocusing on the role of Reelin in cerebral corticalevelopmenten-ichiro Kubo , Takao Honda, Katsutoshi Sekine, Kazuhiro Ishii,enji Tomita, Hidenori Tabata, Kazunori Nakajima

Department of Anatomy, Keio University School of Medicine

uring neocortical development in mammals, neurons are born mainly inhe ventricular zone along the ventricle and migrate radially towards theial surface to be aligned in defined patterns in the cortical plate. These pre-ise patterns of neuronal alignment are regulated by an extracellular matrixrotein, Reelin, which is secreted from Cajal-Retzius neurons in the marginalone of the neocortex. When Reelin binds to its receptors, tyrosine phospho-ylation of the intracellular adaptor protein Disabled 1 (Dab1) is induced.lthough the molecular cascade of Reelin signaling is being uncovered, theiological response of cortical neurons to the Reelin signal remains uncertain.ome previous studies suggested various roles of Reelin. Among them, someppear to be even opposite to each other. For example, some groups arguehat Reelin is inhibitory to migration, but other studies suggest that Reelinromotes migration. To elucidate the biological role of Reelin molecule in theeveloping neocortex, we used the in utero electroporation system. Reelinas expressed ectopically in the developing neocortex and the effect onigrating neurons was analyzed. When enough concentration was acquired,

he ectopic expresssion of Reelin caused marked biological effects in theeveloping cerebral cortices. Based on our findings, we will discuss the rolef Reelin in development of the cerebral cortex.

oi:10.1016/j.neures.2010.07.1090

ch 68S (2010) e223–e334

P2-d12 Prefrontal-enriched SLIT1 expression in primatecortex established during the postnatal developmentTetsuya Sasaki 1 , Yuusuke Komatsu 2, Akiya Watakabe 1, KaoruSawada 1, Tetsuo Yamamori 1

1 Div Brain Biology, Natl Inst Basic Biol, Okazaki 2 Section of Primate ModelDevelopment for Brain Research, National Institute for Physiological Sciences

To elucidate the molecular basis of the specialization of cortical architec-tures, we searched for genes differentially expressed among neocortical areasof Old World monkeys by restriction landmark cDNA scanning (RLCS). Wefound that mRNA of SLIT1, an axon guidance molecule, was enriched in theprefrontal cortex. In situ hybridization analysis revealed that SLIT1 mRNAwas mainly distributed in the middle layers of most cortical areas, robustlyin the prefrontal cortex and faintly in primary sensory areas. The lowestexpression was in the primary visual area. Perinatally, SLIT1 mRNA wasabundantly expressed in the cortex with modest area specificity. Downregu-lation of expression initially occurred in early sensory areas around postnatalday 60 and followed in the association areas. The prefrontal area-enrichedSLIT1 mRNA expression results from a relatively greater attenuation of thisexpression in the other areas. These results suggest that its role is alteredpostnatally, and that this is particularly important for prefrontal connectivityin primate cortex.

doi:10.1016/j.neures.2010.07.1091

P2-d13 Aberrant migration of tyrosine hydroxylase-containing neurons in the olfactory bulb of prokineticintype2 receptor KO mice.Atsuko KuboGraduate School of Medicine Kinki University

Previously, we reported a defect of glomerular layer in the olfactory bulb(OB) of pkr2(/( mice. This is caused by the impairment of Prokineticintype2 (PKR2)-dependent axon elongation of olfactory neurons. In the OB ofadult mice, the glomerular layer contains Dopamine-containing cells namedperiglomerular neurons. Tyrosine Hydroxylase (TH) is a marker to detect thelocalization of the dopamine (DA) neurons. In order to see how the loss ofglomerulus affect the migration and differentiation of the DA neurons in theolfactory bulb, we examined the localization of TH-expressing neurons inthe OB of PKR2 (/( mice at E16, E18 and P0 by immunohistochemical tech-nique using an anti-tyrosine hydroxylase antibody. The pkr2(/( mice embryoand neonates showed abnormal structures in the olfactory system. The sizeof the olfactory bulb was reduced in the PKR2 (/( mice due to the loss ofglomerular layer, as reported previously. In the KO mice, the localization ofTH-expressing cells was disorganized compared with those in the WT mice,and the number was decreased at E16, E18, and P0. As the glomerulus is lostin the KO mice, TH neurons did not migrate into the glomerular layer, but,interestingly, the neurons, eventually, moved to the edge of the olfactorybulb. Therefore, it is highly probable that the most process of migration ofTH-containing neurons were not dependent on the formation of the glomeru-lus. In the adult OB, TH neurons migrated to the edge of the OB. The findingsuggests the existence of unknown attractor, that lead the DA cells migrateto the outside border of the OB.

doi:10.1016/j.neures.2010.07.1092

P2-d14 Analysis of the nuclear translocation mechanism ofDab1 required for layer formation of the cerebral cortexTakao Honda , Kazunori NakajimaDepartment of Anatomy, School of Medicine, Keio University

Reelin is a large glycoprotein secreted from neurons of various regions,including Cajal-Retzius cells in the cortical marginal zone. Disruption of thereelin gene causes neuroanatomical abnormalities such as a defect in the pre-plate splitting and inverted cortical lamination. Dab1 is a cytoplasmic proteinand interacts with at least two Reelin receptors, VLDLR and ApoER2. Theabsence of dab1 causes an almost exact neuroanatomical phenocopy of thereeler (reelin mutant mice). Although Dab1 has been considered a cytoplasmicprotein, we previously showed that Dab1 is a nucleocytoplasmic shuttlingprotein. In its steady state, Dab1 is mainly located in the cytoplasm. However,treatment with leptomycine B, a specific inhibitor of the CRM1, resulted in

nuclear accumulation of Dab1. By using deletion or substitutional mutants ofDab1, we have mapped a classic bipartite nuclear localization signal (cNLS)and two CRM1-dependent nuclear export signals. To reveal the functionalsignificance of Dab1 shuttling, we examined whether mutation to the cNLS ofDab1 inhibits nuclear translocation of Dab1. Unexpectedly, the cNLS mutant