Kawano-Yamashita Emi
| Faculty Division of Natural Sciences Research Group of Biological Sciences | Associate Professor |
Last Updated :2025/06/13
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Profile Information
Name (Japanese)
KAWANOName (Kana)
Emi
Research History
- Jun. 2021 - Present, 奈良女子大学 理学部 化学生物環境学科 准教授
- Apr. 2017 - May 2021, Nara Women's University, Faculty of Science Department of Chemistry, Biology, and Environmental Science, 助教
- Oct. 2014 - Mar. 2017, 日本学術振興会特別研究員（RPD）
- Apr. 2010 - Sep. 2014, 日本学術振興会特別研究員（PD）
- Apr. 2007 - Mar. 2010, 大阪市立大学大学院 理学研究科 博士研究員
- Apr. 2006 - Mar. 2007, 日本学術振興会特別研究員（PD）
- Apr. 2005 - Mar. 2006, 日本学術振興会特別研究員（DC2）
Education
- Apr. 2003 - Mar. 2006, Nara Women's University, Graduate School of Humanities and Sciences, 博士後期課程 共生自然科学専攻, Japan
- Apr. 2001 - Mar. 2003, Nara Women's University, Graduate School of Humanities and Sciences, 博士前期課程 生物科学専攻, Japan
- Apr. 1997 - Mar. 2001, Nara Women's University, Faculty of Science, 生物科学科, Japan
Teaching Experience
■Ⅱ．研究活動実績
Published Papers
- iScience, Light intensity-dependent arrestin switching for inactivation of a light-sensitive GPCR, bistable opsin., Baoguo Shen; Seiji Wada; Tomohiro Sugihara; Takashi Nagata; Haruka Nishioka; Emi Kawano-Yamashita; Takeaki Ozawa; Mitsumasa Koyanagi; Akihisa Terakita, Inactivation of most light-sensitive G protein-coupled receptor (GPCR) opsins involves arrestin binding to terminate cell responses. In the zebrafish pineal organ, UV sensitive parapinopsin 1 (PP1)-expressing cells exhibit color opponency through photoequilibria between two photo-interconvertible states of PP1. The amount of visible light-sensitive active states (photoproducts) is crucial for generating color opponency, raising questions about how and what arrestins are involved in PP1 inactivation. Here, we found two arrestins, Arr3a and Sagb competitively bind to PP1. Photoresponse analyses of the PP1 cells using gene-knockdown larvae revealed Arr3a-involved quick inactivation was switched to Sagb-involved moderate inactivation depending on increased light intensity. Furthermore, we found photoregeneration of PP1 facilitates the dissociation of the PP1-arrestin complex, allowing for continuous arrestin supply in the photoequilibria under strong light. These regulations for the active photoproduct amounts of PP1 may help maintain appropriate color opponency. The current findings provide insight into the dynamics of GPCR inactivation involving multiple arrestins., 21 Feb. 2025, 28, 2, 111706, 111706, Scientific journal, True, 10.1016/j.isci.2024.111706
- Refereed, Cellular and Molecular Life Sciences, Springer Science and Business Media LLC, Functional diversification process of opsin genes for teleost visual and pineal photoreceptions, Chihiro Fujiyabu; Fuki Gyoja; Keita Sato; Emi Kawano-Yamashita; Hideyo Ohuchi; Takehiro G. Kusakabe; Takahiro Yamashita, Abstract
Most vertebrates have a rhodopsin gene with a five-exon structure for visual photoreception. By contrast, teleost fishes have an intron-less rhodopsin gene for visual photoreception and an intron-containing rhodopsin (exo-rhodopsin) gene for pineal photoreception. Here, our analysis of non-teleost and teleost fishes in various lineages of the Actinopterygii reveals that retroduplication after branching of the Polypteriformes produced the intron-less rhodopsin gene for visual photoreception, which converted the parental intron-containing rhodopsin gene into a pineal opsin in the common ancestor of the Teleostei. Additional analysis of a pineal opsin, pinopsin, shows that the pinopsin gene functions as a green-sensitive opsin together with the intron-containing rhodopsin gene for pineal photoreception in tarpon as an evolutionary intermediate state but is missing in other teleost fishes, probably because of the redundancy with the intron-containing rhodopsin gene. We propose an evolutionary scenario where unique retroduplication caused a “domino effect” on the functional diversification of teleost visual and pineal opsin genes., 08 Oct. 2024, 81, 1, Scientific journal, 10.1007/s00018-024-05461-3 - BMC biology, Insights into the evolutionary origin of the pineal color discrimination mechanism from the river lamprey., Seiji Wada; Emi Kawano-Yamashita; Tomohiro Sugihara; Satoshi Tamotsu; Mitsumasa Koyanagi; Akihisa Terakita, BACKGROUND: Pineal-related organs in cyclostomes, teleosts, amphibians, and reptiles exhibit color opponency, generating antagonistic neural responses to different wavelengths of light and thereby sensory information about its "color". Our previous studies suggested that in zebrafish and iguana pineal-related organs, a single photoreceptor cell expressing both UV-sensitive parapinopsin and green-sensitive parietopsin generates color opponency in a "one-cell system." However, it remains unknown to what degree these opsins and the single cell-based mechanism in the pineal color opponency are conserved throughout non-mammalian vertebrates. RESULTS: We found that in the lamprey pineal organ, the two opsins are conserved but that, in contrast to the situation in other vertebrate pineal-related organs, they are expressed in separate photoreceptor cells. Intracellular electrophysiological recordings demonstrated that the parietopsin-expressing photoreceptor cells with Go-type G protein evoke a depolarizing response to visible light. Additionally, spectroscopic analyses revealed that parietopsin with 11-cis 3-dehydroretinal has an absorption maximum at ~570 nm, which is in approximate agreement with the wavelength (~560 nm) that produces the maximum rate of neural firing in pineal ganglion cells exposed to visible light. The vesicular glutamate transporter is localized at both the parietopsin- and parapinopsin-expressing photoreceptor terminals, suggesting that both types of photoreceptor cells use glutamate as a transmitter. Retrograde tracing of the pineal ganglion cells revealed that the terminal of the parietopsin-expressing cells is located close enough to form a neural connection with the ganglion cells, which is similar to our previous observation for the parapinopsin-expressing photoreceptor cells and the ganglion cells. In sum, our observations point to a "two-cell system" in which parietopsin and parapinopsin, expressed separately in two different types of photoreceptor cells, contribute to the generation of color opponency in the pineal ganglion cells. CONCLUSION: Our results indicate that the jawless vertebrate, lamprey, employs a system for color opponency that differes from that described previously in jawed vertebrates. From a physiological viewpoint, we propose an evolutionary insight, the emergence of pineal "one-cell system" from the ancestral "multiple (two)-cell system," showing the opposite evolutionary direction to that of the ocular color opponency., 16 Sep. 2021, 19, 1, 188, 188, Scientific journal, True, 10.1186/s12915-021-01121-1
- Zoological Science, Zoological Society of Japan, Immunohistochemical Characterization of the Development of Long Photoreceptor Cells in the Lamprey Retina, Ferdousi Arjana Hoque; Emi Kawano-Yamashita; Yuka Miyamoto; Satoshi Tamotsu, 13 May 2021, 38, 4, Scientific journal, 10.2108/zs200151
- Zoological letters, Functional identification of an opsin kinase underlying inactivation of the pineal bistable opsin parapinopsin in zebrafish., Baoguo Shen; Seiji Wada; Haruka Nishioka; Takashi Nagata; Emi Kawano-Yamashita; Mitsumasa Koyanagi; Akihisa Terakita, In the pineal organ of zebrafish larvae, the bistable opsin parapinopsin alone generates color opponency between UV and visible light. Our previous study suggested that dark inactivation of the parapinopsin photoproduct, which activates G-proteins, is important for the regulation of the amount of the photoproduct. In turn, the photoproduct is responsible for visible light sensitivity in color opponency. Here, we found that an opsin kinase or a G-protein-coupled receptor kinase (GRK) is involved in inactivation of the active photoproduct of parapinopsin in the pineal photoreceptor cells of zebrafish larvae. We investigated inactivation of the photoproduct in the parapinopsin cells of various knockdown larvae by measuring the light responses of the cells using calcium imaging. We found that GRK7a knockdown slowed recovery of the response of parapinopsin photoreceptor cells, whereas GRK1b knockdown or GRK7b knockdown did not have a remarkable effect, suggesting that GRK7a, a cone-type GRK, is mainly responsible for inactivation of the parapinopsin photoproduct in zebrafish larvae. We also observed a similar knockdown effect on the response of the parapinopsin photoreceptor cells of mutant larvae expressing the opsin SWS1, a UV-sensitive cone opsin, instead of parapinopsin, suggesting that the parapinopsin photoproduct was inactivated in a way similar to that described for cone opsins. We confirmed the immunohistochemical distribution of GRK7a in parapinopsin photoreceptor cells by comparing the immunoreactivity to GRK7 in GRK7a-knockdown and control larvae. These findings suggest that in pineal photoreceptor cells, the cone opsin kinase GRK7a contributes greatly to the inactivation of parapinopsin, which underlies pineal color opponency., 12 Feb. 2021, 7, 1, 1, 1, Scientific journal, True, 10.1186/s40851-021-00171-1
- Refereed, Scientific reports, The non-visual opsins expressed in deep brain neurons projecting to the retina in lampreys., Emi Kawano-Yamashita; Mitsumasa Koyanagi; Seiji Wada; Tomoka Saito; Tomohiro Sugihara; Satoshi Tamotsu; Akihisa Terakita, In lower vertebrates, brain photoreceptor cells express vertebrate-specific non-visual opsins. We previously revealed that a pineal-related organ-specific opsin, parapinopsin, is UV-sensitive and allows pineal wavelength discrimination in lampreys and teleost. The Australian pouched lamprey was recently reported as having two parapinopsin-related genes. We demonstrate that a parapinopsin-like opsin from the Japanese river lamprey exhibits different molecular properties and distribution than parapinopsin. This opsin activates Gi-type G protein in a mammalian cell culture assay in a light-dependent manner. Heterologous action spectroscopy revealed that the opsin forms a violet to blue-sensitive pigment. Interestingly, the opsin is co-localised with green-sensitive P-opsin in the cells of the M5 nucleus of Schober (M5NS) in the mesencephalon of the river and brook lamprey. Some opsins-containing cells of the river lamprey have cilia and others an axon projecting to the retina. The opsins of the brook lamprey are co-localised in the cilia of centrifugal neurons projecting to the retina, suggesting that cells expressing the parapinopsin-like opsin and P-opsin are sensitive to violet to green light. Moreover, we found neural connections between M5NS cells expressing the opsins and the retina. These findings suggest that the retinal activity might be modulated by brain photoreception., 15 Jun. 2020, 10, 1, 9669, 9669, Scientific journal, True, 10.1038/s41598-020-66679-2
- Refereed, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Color opponency with a single kind of bistable opsin in the zebrafish pineal organ, Wada Seiji; Shen Baoguo; Kawano-Yamashita Emi; Nagata Takashi; Hibi Masahiko; Tamotsu Satoshi; Koyanagi Mitsumasa; Terakita Akihisa, 30 Oct. 2018, 115, 44, 11310, 11315, Scientific journal, True, 10.1073/pnas.1802592115
- Refereed, Frontiers in Ecology and Evolution, Frontiers Media S. A, Vertebrate bistable pigment parapinopsin: Implications for emergence of visual signaling and neofunctionalization of non-visual pigment, Mitsumasa Koyanagi; Emi Kawano-Yamashita; Seiji Wada; Akihisa Terakita, 11 Apr. 2017, 5, 23, 10.3389/fevo.2017.00023
- Refereed, PLoS ONE, Public Library of Science, Activation of transducin by bistable pigment parapinopsin in the pineal organ of lower vertebrates, Emi Kawano-Yamashita; Mitsumasa Koyanagi; Seiji Wada; Hisao Tsukamoto; Takashi Nagata; Akihisa Terakita, 22 Oct. 2015, 10, 10, e0141280, Scientific journal, 10.1371/journal.pone.0141280
- Refereed, BMC Biology, BioMed Central Ltd., Diversification of non-visual photopigment parapinopsin in spectral sensitivity for diverse pineal functions, Mitsumasa Koyanagi; Seiji Wada; Emi Kawano-Yamashita; Yuichiro Hara; Shigehiro Kuraku; Shigeaki Kosaka; Koichi Kawakami; Satoshi Tamotsu; Hisao Tsukamoto; Yoshinori Shichida; Akihisa Terakita, 15 Sep. 2015, 13, 1, Scientific journal, 10.1186/s12915-015-0174-9
- Refereed, PLoS ONE, Public Library of Science, Distribution of mammalian-like melanopsin in cyclostome retinas exhibiting a different extent of visual functions, Lanfang Sun; Emi Kawano-Yamashita; Takashi Nagata; Hisao Tsukamoto; Yuji Furutani; Mitsumasa Koyanagi; Akihisa Terakita, 24 Sep. 2014, 9, 9, e108209, Scientific journal, 10.1371/journal.pone.0108209
- Refereed, PLoS ONE, Expression of UV-sensitive parapinopsin in the iguana parietal eyes and its implication in UV-sensitivity in vertebrate pineal-related organs, Seiji Wada; Emi Kawano-Yamashita; Mitsumasa Koyanagi; Akihisa Terakita, 14 Jun. 2012, 7, 6, e39003, Scientific journal, 10.1371/journal.pone.0039003
- Refereed, PLoS ONE, Beta-arrestin functionally regulates the non-bleaching pigment parapinopsin in lamprey pineal, Emi Kawano-Yamashita; Mitsumasa Koyanagi; Yoshinori Shichida; Tadashi Oishi; Satoshi Tamotsu; Akihisa Terakita, 2011, 6, 1, e16402, Scientific journal, 10.1371/journal.pone.0016402
- Refereed, JOURNAL OF EXPERIMENTAL BIOLOGY, Immunohistochemical characterization of a parapinopsin-containing photoreceptor cell involved in the ultraviolet/green discrimination in the pineal organ of the river lamprey Lethenteron japonicum, Emi Kawano-Yamashita; Akihisa Terakita; Mitsumasa Koyanagi; Yoshinori Shichida; Tadashi Oishi; Satoshi Tamotsu, Nov. 2007, 210, 21, 3821, 3829, Scientific journal, 10.1242/jeb.007161
- Refereed, ZOOLOGICAL SCIENCE, Neural interaction of gonadotropin-regulating hormone immunoreactive neurons and the suprachiasmatic nucleus with the paraventricular organ in the Japanese grass lizard (Takydromus Tachydromoides), E Kawano; Y Takahata; T Oishi; K Ukena; K Tsutsui; S Tamotsu, Mar. 2006, 23, 3, 277, 287, Scientific journal, 10.2108/zsj.23.277
- Refereed, Proc. Natl. Acad. Sci. USA, Bistable UV pigment in the lamprey pineal, M Koyanagi; E Kawano; Y Kinugawa; T Oishi; Y Shichida; S Tamotsu; A Terakita, Apr. 2004, 101, 17, 6687, 6691, Scientific journal, 10.1073/pnas.0400819101
MISC
- Advances in experimental medicine and biology, Optogenetic Potentials of Diverse Animal Opsins: Parapinopsin, Peropsin, LWS Bistable Opsin., Mitsumasa Koyanagi; Tomoka Saito; Seiji Wada; Takashi Nagata; Emi Kawano-Yamashita; Akihisa Terakita, Animal opsin-based pigments are light-activated G-protein-coupled receptors (GPCRs), which drive signal transduction cascades via G-proteins. Thousands of animal opsins have been identified, and molecular phylogenetic and biochemical analyses have revealed the unexpected diversity in selectivity of G-protein activation and photochemical property. Here we discuss the optogenetic potentials of diverse animal opsins, particularly recently well-characterized three non-canonical opsins, parapinopsin, peropsin, and LWS bistable opsin. Unlike canonical opsins such as vertebrate visual opsins that have been conventionally used for optogenetic applications, these opsins are bistable; opsin-based pigments do not release the chromophore retinal after light absorption, and the stable photoproducts revert to their original dark states upon subsequent light absorption. Parapinopsins have a "complete photoregeneration ability," which allows a clear color-dependent regulation of signal transductions. On the other hand, peropsins serve as a "dark-active and light-inactivated" GPCR to regulate signal transductions in the opposite way compared with usual opsins. In addition, an LWS bistable opsin from a butterfly was revealed to be the longest wavelength-sensitive animal opsin with its absorption maximum at ~570 nm. The property-dependent optical regulations of signal transductions were demonstrated in mammalian cultured cells, showing potentials of new optogenetic tools., 2021, 1293, 141, 151, True, 10.1007/978-981-15-8763-4_8
- Not Refereed, 2015, 32, 1, 2, 9, 10.3330/hikakuseiriseika.32.2
- Refereed, Wiley Interdisciplinary Reviews: Membrane Transport and Signaling, Evolution and diversity of opsins, Akihisa Terakita; Emi Kawano-Yamashita; Mitsumasa Koyanagi, Jan. 2012, 1, 1, 104, 111, 10.1002/wmts.6
- Not Refereed, 2006, 23, 3, 143, 152, 10.3330/hikakuseiriseika.23.143
- Not Refereed, 2005, 41, 238, 246
- Not Refereed, BIOLOGICAL RHYTHM RESEARCH, Circadian rhythms in amphibians and reptiles: Ecological implications, T Oishi; K Nagai; Y Harada; M Naruse; M Ohtani; E Kawano; S Tamotsu, Feb. 2004, 35, 1-2, 105, 120, 10.1080/09291010412331313278
- Not Refereed, 2004, 21, 4, 185, 194, 10.3330/hikakuseiriseika.21.185
Books etc
Presentations
- Emi Kawano-Yamashita; Chisa Nittagawa; Satoshi Tamotsu; Mitsumasa Koyanagi; Akihisa Terakita, Immunohistochemical investigation of the melanopsin-containing cells in the retina of the larval and adult lampreys, Poster presentation, 02 Dec. 2023
- Sakie Terada; Emi Kawano-Yamashita, Histological investigation of the efferent neurons projecting to the retina in the green spotted pufferfish, Poster presentation, Dec. 2023
- Poster presentation, Aug. 2023
- Emi Kawano-Yamashita; Ryo Kishimoto; Nanaho Yura; Satoshi Tamotsu, Immunohistochemical investigation of the development of deep brain photoreceptor in larval and adult lamprey, Poster presentation, 05 Dec. 2021
- Oral presentation, 02 Sep. 2021
- 23 Nov. 2020
- Emi KAWANO-YAMASHITA, The deep brain photoreceptor expressing non-visual opsins in lampreys, 04 Sep. 2020, 04 Sep. 2020 - 05 Sep. 2020
- Poster presentation
- Poster presentation
- Oral presentation
- Oral presentation
Research Projects
- 基盤研究(C), 01 Apr. 2024 - 31 Mar. 2027, 24K09531, 脳内光受容器官が協調的に機能する光受容システムの解析, 山下 絵美, 日本学術振興会, 科学研究費助成事業, 奈良女子大学, 4550000, 3500000, 1050000, kaken
- 基盤研究(C), 01 Apr. 2021 - 31 Mar. 2024, 21K06265, 非視覚の光受容がもたらす新しい生理機能の探索, 山下 絵美, 日本学術振興会, 科学研究費助成事業 基盤研究(C), 奈良女子大学, 4160000, 3200000, 960000, 近年、無顎類ヤツメウナギ脳から、新規の光受容タンパク質（bPPL）遺伝子を単離した。光受容タンパク質bPPLの詳細な解析を行い、それが青色光感受性の光受容タンパク質であり、中脳のシェーバーのM5核と呼ばれる、網膜に直接神経投射する遠心性神経（向網膜系ニューロン）で構成される神経核に局在することを発見した。そこで本研究では、ヤツメウナギ中脳シェーバーのM5核に存在する新規脳深部光受容器官が、どのような光情報を、網膜のどの細胞に伝達し、どのような生理機能の調節に関わるのかを調べることで、「脳内で受容した光情報を眼で利用する」という新しい光受容機能の可能性について検討する。
本年度は、中脳シェーバーのM5核の新規脳深部光受容細胞が、どのような光情報を出力するのかを検討するために、これらの細胞群で働く神経伝達物質やその合成酵素の同定を試みたが、本年度に行った実験ではそれらを特定することができなかった。次に、M5核の光受容細胞がどの種類の網膜細胞に光情報を伝達するのかを調べるために、詳細な組織学的解析を行ったところ、向網膜系ニューロンの軸索が投射する網膜細胞の種類を特定することができた。得られた結果は、新規の脳内光受容器官が担う生理機能を考える上で有用な知見であり、機能解明に向けて大きく前進したものと考えられた。加えて、ヤツメウナギの行動と光照射の関連について、予備的な調査を行ったところ、光に影響を受ける遊泳行動が観察された。, kaken - Grant-in-Aid for Scientific Research (C), 01 Apr. 2018 - 31 Mar. 2021, 18K06336, The characterization of the deep brain photoreceptor expressing non-visual opsins., KAWANO-YAMASHITA Emi, Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Nara Women's University, 4290000, 3300000, 990000, We isolated a non-visual opsin, bPPL, from the lamprey brain, and we found a new deep brain photoreceptor expressing bPPL. In this study, we investigated the characteristic of the bPPL-expressing cells with the cell biological analysis using cultured cell and histological analysis such as the retrograde labelling with neural tracer. Heterologous action spectroscopy using the cellular assay showed that bPPL formed a violet to blue-sensitive pigment. Moreover, the bPPL-containing cells had an axon projecting to the retina. These findings suggest that the bPPL-containing cells are sensitive to violet to blue light and transmit the light information to the retina., kaken
- 特別研究員奨励費, Apr. 2014 - Mar. 2017, 14J40094, Principal investigator, 光受容タンパク質パラピノプシンを起点とする松果体及び副松果体の光受容機能の解析, 山下 絵美, 日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 大阪市立大学, 4810000, 3700000, 1110000, ゼブラフィッシュ松果体と副松果体に存在する紫外光受容型パラピノプシンPP1が関わる多様な光受容機能を理解するために、以下の解析を行った。
１、ゼブラフィッシュ松果体において、PP1がどのような生理機能を担うのかを明らかにすることを目指し、本年度は、様々な光条件下でのゼブラフィッシュの遊泳行動解析を行うために、LED照射装置を用いて水槽全体にUV光照射する装置を設計し、その作製を完了した。
２、ゼブラフィッシュ副松果体におけるPP1発現細胞の特徴や機能についての知見を得るために、形態学的手法を中心とした解析を試みた。
・副松果体にどのような種類の光受容タンパク質が発現するのかを明らかにするために、松果体での発現が主に知られているPP2（可視光受容型パラピノプシン）、エクソロドプシン、赤錐体オプシンなどの光受容タンパク質について、免疫組織化学的に局在を調べた。その結果、副松果体での光受容タンパク質の発現パターンは松果体とは異なることが明らかになった。
・副松果体のPP1発現細胞が関わる機能を推定するために、まず、松果体の主な生理機能のひとつであるメラトニン合成・分泌に関わるかどうかを調べた。具体的には、メラトニンの前駆物質であるセロトニンの免疫組織化学的局在を検討した結果、副松果体では、セロトニンの免疫反応は観察されず、メラトニン合成・分泌に関わらない可能性が推測された。また、副松果体の関与が示唆される機能として、発生初期段階における脳の左右非対称形成にも着目し、それらに対するPP1によるUV光受容の影響を調べることを目指した。その準備段階として、副松果体が影響を及ぼすと考えられる脳領域（手綱核）の非対称性を示す組織学的解析に着手した。具体的には、LD条件下で飼育した野生型稚魚を用いて、左手綱核に多く発現するlovの発現パターンをin situ hybridizationで確認した。, kaken - 特別研究員奨励費, Apr. 2010 - Mar. 2014, 10J07650, Principal investigator, 光受容タンパク質パラピノプシンを基盤とする松果体の色検出応答の生理学的解析, 山下(川野) 絵美; 山下 絵美, 日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 大阪市立大学, 4286808, 4016808, 270000, 下等脊椎動物の松果体には、紫外光と可視光の比率を検出する「色検出応答」が存在し、これまでに、パラピノプシンが松果体の紫外光受容の分子基盤であることを同定してきた。昨年度までの研究から、硬骨魚類ゼブラフィッシュにおいて、松果体と副松果体の両方に、パラピノプシンを発現していることを確認した。さらに、松果体のパラピノプシン発現細胞は神経節細胞を介して、副松果体のパラピノプシン発現細胞は（神経節細胞を介さず）直接的に、共に間脳の手綱核と呼ばれる領域に神経投射する可能性を見いだした。本年度は、松果体の色情報が手綱核に伝達されるのかについて、神経トレーサー法による検証実験を続けて行った。具体的には、パラピノプシン発現細胞に蛍光物質であるGFP（細胞全体を標識）を発現する遺伝子導入ゼブラフィッシュを用いて、手綱核にニューロビオチンやデキストランなどの神経トレーサー物質を取り込ませ、手綱核を中心とした神経回路について調べた。その結果、松果体に存在するGFP標識されたパラピノプシン発現細胞の神経終末と、手綱核からの神経トレーサー物質の注入により逆行性標識された神経節細胞の一部が接する様子が、共焦点レーザー顕微鏡を用いた解析により観察された。すなわち、パラピノプシンを含む紫外光受容細胞を出発点とする松果体由来の色情報は、神経節細胞を介して、手綱核へ伝達されるという、昨年度までの研究結果を裏付けるさらなる組織学的知見が得られた。, kaken
- 特別研究員奨励費, 2005 - 2006, 05J00204, カワヤツメ松果体における紫外光受容システムを中心とした波長識別機構の生理的役割, 山下 絵美, 日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 奈良女子大学, 1800000, 1800000, 下等脊椎動物の松果体には、緑色光で興奮性、UV光で抑制性応答する感色性神経節細胞があり、それらは波長識別を行うと考えられる。本研究は、カワヤツメ松果体を用いて、眼外の波長識別機構の解明を目的とする。これまでに、波長識別の光入力を担うUV色素パラピノプシンを同定し、UV光受容細胞からの伝達経路を明らかにしてきた。そこで、UV光受容システムと、引き起こされる波長識別の特性の解明を目指した。
感色性神経節細胞は応答様式から波長識別を行うと考えられたが、照射光中の波長成分の違いが実際に神経応答に反映されるかは明らかではない。そこで、細胞外誘導によりUV光と緑色光の比率の変化がもたらす応答性の違いについて検証した。具体的には、背景光に緑色光、テスト光にUV光を用い、UV光強度を段階的に強くし、応答に変化が見られるかをスパイク増減の割合により評価した。まず、緑色光照射でスパイクの発火頻度が増加し、UV光を重ねて照射するとスパイクが抑制された。UV光強度を段階的に上げ、照射光中のUV光の比率を高くすると、スパイク抑制の持続時間が長くなり、感色性応答はスパイク頻度を変化させ照射光中のUV/緑色光の比率を検出して波長識別を行う事が証明された。
組織学的に、UV光受容細胞と神経節細胞が直接連絡する事を明らかした。そこで実際に、シナプスを介した情報伝達がなされるかをシナプス遮断薬CoCl_2の投与により電気生理学的に検証した。すると、感色性応答が記録された後に、CoCl_2投与で神経節細胞の光反応が消失、リンガー液での洗浄後に再度記録され、感色性応答の興奮性、抑制性応答は共に光受容細胞からのシナプスを介した情報伝達により起こる反応であると示唆された。
これらより、感色性応答は緑色光を基準に照射光中のUV光の比率を検出し、そのUV光情報はパラピノプシン細胞から直接シナプスを介して伝達されると考えられた。, kaken - Apr. 2003 - Feb. 2004, Principal investigator, 下等脊椎動物網膜外光受容器官における光情報変換機構に関する電気生理学的解析, 川野絵美, 財団法人 日本科学協会, 笹川科学研究助成, 奈良女子大学
■Ⅲ．社会連携活動実績
１．公的団体の委員等（審議会、国家試験委員、他大学評価委員，科研費審査委員等）
- 日本比較生理生化学会, 会計幹事（賛助会員担当）, Jan. 2024 - Present
- （公社）日本動物学会近畿支部, 支部委員, Sep. 2020 - Present, Society
- （公社）日本動物学会近畿支部, 教育委員会委員, May 2020 - Present, Society
- 日本比較生理生化学会, 日本光生物学協会委員, Jan. 2020 - Dec. 2021, Society
- 日本比較生理生化学会, 評議委員, Jan. 2016 - Dec. 2019, Society
- （公社）日本動物学会, 第90回大阪大会実行委員, Sep. 2019 - Sep. 2019, Society
- 日本比較生理生化学会, 第40回神戸大会実行委員, Nov. 2018 - Nov. 2018, Society
