透過您的圖書館登入
IP:3.214.184.69
  • 學位論文

記憶突變果蠅-Mampus之影像和記憶行為分析

Genetic Anatomy of a Memory Mutant, Mampus

指導教授 : 江安世

摘要


果蠅具有五種記憶層次,分別是學習、短期記憶、中期記憶、抗昏迷記憶及長期記憶。記憶可以隨著時間由較不穩定的形式轉變到可抗其他外在干擾並可長時間維持的記憶。抗昏迷記憶就是這種記憶之ㄧ,其是即使經過冰昏但仍存在的記憶。而名為蘿蔔(radish)的突變株是第一個被發現喪失此抗昏迷記憶的果蠅。目前對此抗昏迷記憶的分子機制、基因所屬或細胞中的化學機制的研究仍還有許多未知。再此篇研究我們發現了另一個由跳躍子插在escargo這個基因上游所導致的突變株—Mampus,同樣參與這種抗昏迷記憶的形成。另外我們也篩選到其他三個突變株和Mampus一樣在蛹的中期發展完成並同樣在果蠅腦的前側方表現兩對成雙的神經細胞。同時我們利用FLIP-OUT的技術使Mampus一次只表現出一顆神經細胞進而研究神經伸展方式,我發現Mampus的神經細胞在腦中會先將神經纖維伸展到其細胞同側的後上腦最後伸到神經細胞異側的後上腦。而其表現的四顆神經細胞可分類為兩種不同的型態,第一類的神經細胞會在同側的後上腦有較多的神經纖維,第二類則是在異側的後上腦有較多的神經纖維表現。利用專一在神經樹突及軸突表現的工具我發現Mampus的樹突可能是位於腦中的觸角區而軸突位在後上腦。同時這兩對神經細胞的Gal4活性會被Cha-Gal80抑制所以可能是利用乙烯膽鹼作為其神經傳導物質。當利用神經傳導抑制的基因表現在Mampus的神經細胞來抑制此神經的功能時,發現會干擾其抗昏迷記憶的形成。同時我也利用一種導致細胞死亡的基因shibire在Mampus神經細胞表現時也發現其抗昏迷記憶喪失的現象。未來為了更進一步研究此記憶,我也同時篩選到兩個表現在Mampus神經的突變株分別是8165和6356並可利用此兩個突變株深入研究此記憶型式,此兩個突變是利用engrailed基因的啟動子插入所產生的。根據之前的研究及以上種種的結果皆顯示抗昏迷記憶的形成或讀取皆需要蘿蔔(radish)和Mampus這兩個突變株的基因及其神經細胞的操控。

並列摘要


There are five distinct memory phases in Drosophila, in terms of temporal sustains: Learning, short-term memory (STM), middle-term memory (MTM), (anesthesia resistant memory) ARM and (long-term memory) LTM. With time the memories can be transferred from labile into long-lasting form that are resistant to mental interruptions. ARM is the one that can resist the anesthesia agent -- cold shock. A point mutation fly, radish is the only reported case which has defective ARM. Little is known about the molecular, genetic, or cellular pathways underlying ARM. Here, we report another mutant, Mampus, involved in ARM formation. The Mampus mutant has a GAL4 insertion at upstream of escargot (esg). We have obtained or collected three Mampus alleles with similar expression patterns in two pairs of anterior lateral neurons since mid-pupa stage. Using genetic FLIP-out technique to visualize one neuron at a time, I found that both Mampus neurons project fibers first to the antennal lobe, and then extend proteriorly to the ipsilateral posterior superior protocerebrum (PSP) and finally terminate at contralateral PSP. The two neurons are however different in morphology. One has more fibers at the ipsilateral PSP while the other has more fibers at the contralateral PSP. Using specific polarity reporters, I found that Mampus fibers at antennal lobe are dendrites and at PSP are axons. The two pairs of Mampus neurons are likely cholinergic since their GAL4 expression is inhibited by the expression of Cha-GAL80. When blocking neurotransmitter release from Mampus neurons with shibirets, ARM is disrupted. An independent manipulation by the ablation of Mampus with reaper toxin also disrupts ARM. For a more thorough behavior assay in the future, I have also obtained two promoter-driven lines of engrailed (6356 and 8165) that also expresses in the Mampus neurons. These results together with previous study suggest that formation or retrieval of ARM requires neurons expressing genes disrupted in radish and Mampus mutants in the fly brain.

並列關鍵字

無資料

參考文獻


1. Jefferis, G.S., Marin, E.C., Watts, R.J., and Luo, L. (2002). Development of neuronal connectivity in Drosophila antennal lobes and mushroom bodies. Curr Opin Neurobiol 12, 80-86.
2. Stocker, R.F. (1994). The organization of the chemosensory system in Drosophila melanogaster: a review. Cell Tissue Res 275, 3-26.
3. Dubnau, J., and Tully, T. (1998). Gene discovery in Drosophila: new insights for learning and memory. Annu Rev Neurosci 21, 407-444.
4. Perazzona, B., Isabel, G., Preat, T., and Davis, R.L. (2004). The role of cAMP response element-binding protein in Drosophila long-term memory. J Neurosci 24, 8823-8828.
5. Yin, J.C., Wallach, J.S., Del Vecchio, M., Wilder, E.L., Zhou, H., Quinn, W.G., and Tully, T. (1994). Induction of a dominant negative CREB transgene specifically blocks long-term memory in Drosophila. Cell 79, 49-58.

延伸閱讀