Expression pattern of cadherins in naked mole rat (Heterocephalus glaber) suggests innate cortical diversification of the cerebrum

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Abstracts / Neuroscience Research 71S (2011) e108–e415

ingly, typical ritual behaviors for courtship were normal in Dark-fly, but pairs of Dark-fly male and female copulated quickly even in dark conditions. Therefore, we suggest that multimodal sensory signals regulating courtship behaviors might be stronger in Dark-fly. The composition of Dark-fly’s cuticle hydrocarbons, known as sexual pheromone, was characteristic, and Dark-fly exhibited preference for kin’s chemical signals. On the other hand, courtship song played by Dark-fly male was mostly identical to that of the wild-type male, but Dark-fly seems to be sensitive to a smaller volume of song. Our results suggest that olfactory and auditory signals for courtship behaviors might have evolved under the vision-less environment. To precisely evaluate behaviors excited by sensory signals, we constructed automatic quantitative systems for analyzing fly’s behaviors. We will present the results of analysis of olfactory- and auditory-based behaviors and will discuss Dark-fly’s adaptive behaviors. Research fund: Kyoto University Global COE Program (biodiversity), Leave a nest Co., Leaveanest Grant.

genitor cells express Olig2 (pMN domain). Nkx2.2 is expressed in progenitor cell pool that was located just ventral to pMN domain (p3 domain). Moreover, it was reported that Nkx2.2 has an inhibitory role in motoneuron generation. We previously established method to analyze cell lineage of chick spinal cord cells in a genetically defined manner (Gotoh et al., Dev. Biol., 2011). By using this method, we found that nkx2.2-expressing progenitor cells differentiate into somatic motoneuron in addition to V3 type interneuron. Our finding suggests the existence of novel developmental origin of motoneuron. In additon, we will discuss the contribution of nkx2.2-lineage cell to subtypes of motoneuron.

doi:10.1016/j.neures.2011.07.1507

Shizuko Murakami 1 , Hiroko Ohki-Hamazaki 2 , Yasuo Uchiyama 1

P4-g16 Expression pattern of cadherins in naked mole rat (Heterocephalus glaber) suggests innate cortical diversification of the cerebrum Eiji Matsunaga 1 Okanoya 2,3

, Sanae

Nambu 1,2 , Atsushi

Iriki 1 , Kazuo

1

Lab for Symbolic Cognitive Development, RIKEN BSI 2 RIKEN BSI, Lab for Biolinguistics, Wako, Japan 3 Dep of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo The cerebral cortex is an indispensable region for higher cognitive function that is remarkably diverse among mammalian species. Although previous research has shown that the cortical area map in the mammalian cerebral cortex is formed by innate and activity-dependent mechanisms, it remains unknown how these mechanisms contribute to the evolution and diversification of the functional cortical areas in various species. The naked mole rat (Heterocephalus glaber) is an subterranean eusocial rodent. Physiological and anatomical studies have revealed that the visual system is regressed and the somatosensory system is enlarged. To examine whether species differences in cortical area development are caused by intrinsic factors or environmental factors, we performed comparative gene expression analysis of neonatal naked mole rat and mouse brains. The expression domain of cadherin-6, a somatosensory marker, was expanded caudally and shifted dorsally in the cortex, whereas the expression domain of cadherin-8, a visual marker, was reduced caudally in the neonatal naked mole rat cortex. The expression domain of cadherin-8 was also reduced in other visual areas, such as the lateral geniculate nucleus and superior colliculus. Immunohistochemical analysis of thalamocortical fibers further suggested that somatosensory input did not affect cortical gene expression in the neonatal naked mole rat brain. These results suggest that the development of the somatosensory system and the regression of the visual system in the naked mole rat cortex are due to intrinsic genetic mechanisms, as well as sensory input-dependent mechanisms. Intrinsic genetic mechanisms thus appear to contribute to species diversity in cortical area formation. Research fund: RIKEN Special Postdoctoral Researchers Program, Japan Society of Promotion of Science (21700365), and Takeda Science Foundation. doi:10.1016/j.neures.2011.07.1508

P4-g17 Generation of somatic motoneurons from Nkx2.2expressing progenitor cells in chick embryonic spinal cord Hitoshi Gotoh 1,2 , Katsuhiko Ono 1,2,3 , Hirohide Takebayashi 2,3,4 , Harukazu Nakamura 5 , Hidekiyo Harada 5 , Kazuhiro Ikenaka 2,3 1

Dep. of Biology, Kyoto Pref. University of Med., Kyoto 2 Div. of Neurobiol. and Bioinformatics, Aichi 3 Dept. of Phys. Sci., The Grad. Univ. of Advanced Studies (Sokendai), Miki-cho, Kanagawa 4 Dept. of Morphological Neural Science, Grad. Sch. of Med. Sci., Kumamoto Univ., Kumamoto 5 Dept. of Molecular Neurobiology, Grad. Sch. of Life Sciences and Inst. of Development, Aging and Cancer, Tohoku University, Miyagi In spinal cord, motoneurons and interneurons function coordinately to regulate motor behavior. Diverse classes of motoneurons are present throughout rostro-caudal axis of spinal cord, such as medial motor neurons projecting to axial muscle or lateral motor neurons projecting to limb muscles. It was reported that differentiation of motoneurons subtypes are dependent on the expression of transcription factors, such as Lhx3. However, it remains unclear whether their origins are homogeneous or not. During development, motoneurons are generated from restricted area of neural tube where pro-

doi:10.1016/j.neures.2011.07.1509

P4-g18 The fate of cells expressing somatostatin mRNA and co-migrating with GnRH neurons from the olfactory epithelium to the forebrain 1 Department of Cell Biology and Neuroscience, Juntendo University School of Medicine, Tokyo, Japan 2 Division of Biology, College of Liberal Arts and Science, Kitasato University, Kanagawa, Japan

The phenomenon of cell migration from the olfactory placode has been reported in various vertebrate. In chick embryos, SST mRNA-positive cells were detected in the epithelium of the olfactory placode and mescenchymal tissue just beneath the epithelium at embryonic day (E) 2.5. With development proceed progressively, SST mRNA-positive cells were found in the extending axons of the olfactory nerve and the medial forebrain adjacent to the migrating GnRH neurons. Ablation of the chick olfactory placode at E2.5–3.5 resulted in the loss of SST mRNA-positive cells in the migratory mass of GnRH neurons of the medial forebrain on the operated side at E7.5. These results raise the possibility that a subpopulation of SST mRNA-positive cells in the adult chick forebrain originates from the olfactory placode. To examine the fate of cells expressing SST mRNA derived from the olfactory placode, epithelial cells of the olfactory placode were labeled using the Tol2 transposon system. E2.5–3 chick embryos were electroporated in the olfactory pit region to transfer a Tol2-based vector containing the EGFP gene with a transposase expression vector which is kindly provided by Dr. Kawakami, NIG, and were incubated until E17. GFP expression was found in part of the olfactory epithelium in the electroporated side at E17. A small number of GFP-expressing cells were observed in the medial forebrain. A double immunohistochemical study showed that most GFP-positive cells were located near the GnRH neurons. For detection of the SST mRNA on the GFP-expressing cells, the combination of fluorescent in situ hybridization and immunohistochemistry was performed. A few GFP-positive cells co-expressed the SST mRNA in the medial forebrain. These results clearly demonstrated that cells expressing SST mRNA and co-migrating with GnRH neurons originated in the olfactory placode and settled in the medial forebrain where GnRH neurons are distributed. doi:10.1016/j.neures.2011.07.1510

P4-g19 Regulation of dendritic spine morphology by FILIP Hideshi Yagi 1,3 , Min-Jue Xie 1,3 , Hiroshi Ikeda 2,3 , Munekazu Komada 1 , Tokuichi Iguchi 1,3 , Kazuki Kuroda 1,3 , Masaru Okabe 4 , Makoto Sato 1,3 1 Div. Cell Biol. Neurosci., Dept. Morphol. Physiol., Fac. Med. Sci., Univ. Fukui, Fukui, Japan 2 Dept. Human & AI Sys., Univ. Fukui, Fukui, Japan 3 Res. Edu. Program Life Sci., University Fukui, Fukui, Japan 4 GIRC, Osaka Univ, Osaka, Japan

In order to investigate the function of FILIP (Filamin A-interacting protein) in vivo, we generated the FILIP knockout (FILIP-KO) mice. We study on radial migration of FILIP-KO mice using the in utero electroporation method. FILIPKO mice showed displacement of the neurons in the cortex compared with their wild-type or heterozygous littermates. This result indicated that FILIPKO mice had a disturbance in the radial migration as expected from our previous results; the overexpression of FILIP in the migrating neurons disturbed the radial migration. Further we revealed FILIP expression in the adult brain by visualizing activity of ␤-galactosidase that expressed under the control of FILIP promoter in the FILIP-KO mice. The expression of FILIP was observed in telencephalon, especially glutamatergic neuron of piriform cortex. The significance of FILIP in the adult brain has remained open. We then thoroughly examined on the morphology of neurons using Golgi-Cox staining method. The mean length of spines on the apical dendrite of pyramidal neurons in the piriform cortex was shorter in the FILIP-KO mice than that of wild-type and heterozygous littermates. We observed that exogenous FILIP