細胞極性確立とmRNA局在のin vivo イメージング

• 研究課題/領域番号: 11242202
• 研究種目: 特定領域研究
• 配分区分: 補助金
• 審査区分: 生物系
• 研究機関: 大阪大学 (2001-2003); 名古屋大学 (1999-2000)
• 研究代表者: 入江 賢児 大阪大学, 医学系研究科, 助教授 (90232628)
• 研究期間 (年度): 1999 – 2003
• 研究課題ステータス: 完了 (2003年度)
• 配分額: 55,900千円 (直接経費: 55,900千円); 2003年度: 8,500千円 (直接経費: 8,500千円); 2002年度: 8,500千円 (直接経費: 8,500千円); 2001年度: 12,700千円 (直接経費: 12,700千円); 2000年度: 12,700千円 (直接経費: 12,700千円); 1999年度: 13,500千円 (直接経費: 13,500千円)
• キーワード: 非対称分裂 / mRNA / RNA結合蛋白質 / 酵母 / 細胞骨格 / アクチン / 翻訳 / ミオシン / RNA結合タンパク質 / ASHI / シオシン / GFP

研究概要

本研究では、細胞極性の分子レベルでの研究が最も進んでいる出芽酵母を用いて、mRNAや細胞極性決定因子の局在のin vivoイメージングの系を確立し、その系を用いてmRNAの細胞内局在の分子機構機構および細胞極性の確立や維持に関与する因子のmRNA局在における機能を明らかにする。また、動物細胞から酵母相同遺伝子を機能的に分離することにより、動物細胞におけるmRNAの局在機構およびその細胞極性との関連を明らかにする。さらに、動物細胞において細胞極性の形成に重要な役割を果たす細胞間接着の形成機構について解析する。本年度は、酵母および培養細胞を用いた細胞極性、非対称分裂、mRNAの局在、細胞間接着形成の機構の解析から、以下の結果を得た。
(1)NucleaseドメインをもつMkt1がPbp1と複合体を形成して、HO mRNAの3'非翻訳領域を介して、HO遺伝子の発現を正に制御することを明らかにした。
(2)ASH1 mRNAの娘細胞の先端への局在に必要なShe4が、ASH1 mRNAを輸送するMyo4モータータンパク質のシャペロンであることを明らかにした。
(3)上皮細胞における細胞間接着形成時において、接着分子ネクチン-3が、運動している細胞の先端部に局在するネクチン様分子Nec1-5とヘテロな接着を形成し、この接着がアドヘレンスジャンクション形成の初期に機能することを見出した。
(4)上皮細胞のアドヘレンスジャンクションにおいて、アドヘレンスジャンクション形成における2つの細胞間接着機構、ネクチン-アファディン系とカドヘリン-カテニン系を連結する因子ADIP,LMO7を見出した。
このように、本年度の研究は予想以上に進展し、当初の目的を達成することができた。

研究成果

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