Minute sexual dimorphism in gametes of green seaweed Ulva shed light on cell-to-cell recognition and fusion mechanisms

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K06242
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44040:Morphology and anatomical structure-related
• Research Institution: Hokkaido University
• Principal Investigator: Ichihara Kensuke 北海道大学, 北方生物圏フィールド科学センター, 助教 (60610095)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 海藻 / 有性生殖 / ゲノム編集 / 配偶子接合

Outline of Final Research Achievements

The purpose of this study was to elucidate the entities and functions of proteins that play important roles in "recognition" and "fusion (fertilization)" between the male and female gametes of the marine green alga blue-green algae. From the comparative proteomes between male and female gametes, we were able to identify proteins related to "recognition" and "fusion (fertilization). For one of the proteins (GEX2), we were able to show that the male gametes whose genes were disrupted by genome editing lost fertilization ability, and that this protein is located near the male mating structure (fertilization initiation apparatus).

Free Research Field

藻類学

Academic Significance and Societal Importance of the Research Achievements

アオノリの配偶子接合は非常に単純で原始的であるが、この単純さは有性生殖の根幹である配偶子間の「認識」と「融合」の仕組みを解き明かす上では、大きな利点である。被子植物や動物では受精時の配偶子間の細胞膜の動態を観察することは組織の複雑さから困難を伴うが、アオノリでは配偶子間の膜の接着や融合をより簡便に直接観察することができる。この構造的な単純さを利用することで、細胞がお互いを正しく認識し融合する仕組みを解き明かしたい。植物では受精に関わる遺伝子は藻類から陸上植物まで保存されているものが多く、海藻で明らかにした受精の仕組みを有用作物の品種改良などへ還元することも期待できる。