Elucidation of developmental mechanisms of motor neurons that innervate the avian cucullaris muscle

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K06835
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 48010:Anatomy-related
• Research Institution: Fukushima Medical University
• Principal Investigator: Yaginuma Hiroyuki 福島県立医科大学, 医学部, 教授 (90230193)
• Co-Investigator(Kenkyū-buntansha): 向笠 勝貴 福島県立医科大学, 医学部, 助教 (60706349) ; 本間 俊作 福島県立医科大学, 医学部, 准教授 (20261795) ; 渡邉 裕二 福島県立医科大学, 医学部, 講師 (80301042)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 僧帽筋 / 副神経 / MiR-9 / Homeobox / ROBO3 / 運動神経 / 頚髄

Outline of Final Research Achievements

In this study, we investigated the pathway formation by axons of motor neurons that innervate the trapezius muscle (SAN/dMN) and the molecular mechanisms of development and differentiation of SAN/dMN, including the differentiation of the p3 region, which is their precursor domain. The main results are as follows. (1) It was found that the spinal accessory nerve extending from SAN / dMNs was formed at st20 (E3-3.5). (2) It was clarified that the forced expression of ectopic Hox molecules does not affect the development of SAN/dMN. (3) Forced expression of microRNA-9 prevented the dorsal migration of SAN/dMN. In addition, precocious expression of ROBO3 was observed in the p3 region. (4) The regulation mechanism of ROBO3 expression and its species difference between tetrapods and teleosts was clarified.

Free Research Field

発生学　神経解剖学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果は、これまでの僧帽筋を支配する運動神経の発達に関する理解に新しい知見を加えるものである。特に運動神経を含めて体の吻尾軸における構造の決定に関するHox分子の異所性発現によってSAN/dMNの分化に影響が見られなかったことは興味深く、今後のさらなる研究の必要性を示している。また、SAN/dMNの分化とはまだ直接結びつかないが、MiR-9発現の影響の解析から発展し、ROBO3の発現調整に係わるcis-regulatory moduleの同定を行い、硬骨魚類と四足動物間の種差を明らかにしたことは学問的な価値が高いと思われる。