Studies on the developmental mechanisms of neurons in the left-right asymmetric brain of the Ciona larva with the single cell resolution

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K16150
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 44020:Developmental biology-related
• Research Institution: Hokkaido University (2020-2021); Konan University (2019)
• Principal Investigator: Oonuma Kouhei 北海道大学, 遺伝子病制御研究所, 助教 (70774876)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: ホヤ / 脳 / 左右非対称 / 細胞系譜 / 遺伝子発現制御

Outline of Final Research Achievements

The larva of the ascidian Ciona intestinalis type A (Ciona robusta), which has only 300 cells of the central nervous system, is a useful model for understanding the developmental mechanisms of the nervous system at the single-cell resolution. Recently, in the process of studying the cell lineage of the brain in the Ciona larva, I found that the left-right asymmetry of the brain is more complex than previously reported. However, the developmental mechanisms that develop the left-right asymmetric brain are poorly understood, including in other animals. In this study, I aimed to elucidate the cell lineage of the brain in the Ciona larva and the gene expression regulatory networks (GRNs) that regulate the development of the brain. During 2019-2021, I revealed the complete cell lineage of dopaminergic cells (DA cells), gravity-sensing cells, and lens cells in the brain of the Ciona larva. In addition, I revealed the partial GRNs of the DA cells and the gravity-sensing cells.

Free Research Field

発生生物学

Academic Significance and Societal Importance of the Research Achievements

本研究は、ホヤ胚の卵膜除去による脳胞の構造や左右性の異常という技術的な問題を解決し、正常な脳にあるドーパミン産生細胞やレンズ細胞の、受精卵を起点とした細胞系譜を完全に明らかにした。また、この明らかにした細胞系譜の情報を基に、ドーパミン産生細胞の特異化や決定が生じる時期と、特異化に重要な因子を明らかにした。他の神経細胞についても、その細胞系譜と発生機序の一端を明らかにした。以上の成果により、ホヤと脊椎動物とで脳（特にドーパミン産生細胞）の発生機序を単一細胞レベルで比較するための土台を初めて築いた。今後、本研究の成果を基にした、単一細胞レベルでの神経回路形成の解析や機能解析への展開が期待される。