Mechanisms for the establishment of the zic1 expression boundary in the teleost trunk

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K07364
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Developmental biology
• Research Institution: The University of Tokyo
• Principal Investigator: Shimada Atsuko 東京大学, 大学院理学系研究科(理学部), 客員共同研究員 (20376552)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 遺伝子発現境界 / 体節 / zic1

Outline of Final Research Achievements

Establishment of gene expression boundary is crucial for creating elaborate morphology during development. We examined the establishment of zic1/zic4-expression boundary demarcating dorsoventral boundary of the entire trunk of medaka fish (Oryzias latipes), and identified a subgroup of dermomyotomal cells, called horizontal boundary cells (HBCs) as crucial players for the boundary formation. Embryological and genetic analyses demonstrated that HBCs play crucial roles in the two major events of the process, i.e. refinement and maintenance. In the refinement, HBCs could serve as a chemical barrier against Wnts from the neural tube by expressing Hhip. At later stages, HBCs participate in the maintenance of the boundary by differentiating into the horizontal myoseptum physically inhibiting cell mixing across the boundary. These findings reveal the mechanisms underlying the dorsoventral boundary in the teleost trunk by specialized boundary cells.

Free Research Field

発生学

Academic Significance and Societal Importance of the Research Achievements

本研究では、メダカ体節の背腹中心部に出現する新規細胞群Boundary cellsを同定し、この細胞群が背腹を分断しつつzic1発現境界を形成することで体幹部を背腹のコンパートメントに分けることを示した。従来わかっていたコンパートメント形成メカニズムは、区画間の細胞同士の相互作用に着目したものであり（接着性の違い等）、本研究が提唱する特殊な細胞による遺伝子発現境界形成は新規なコンパートメント形成メカニズムである。このようなメカニズムは、大型のからだを有する脊椎動物のかたちをロバストに維持するための普遍的な戦略である可能性があり学術的に意義がある。