在大腸桿菌中建立第二極以人工實現穩健不對稱細胞分裂

Establishment of the second pole for a robust synthetic asymmetric cell division in Escherichia coli

范浩俊(Hao-Chun Fan)

指導教授 ： 黃筱鈞

國立臺灣大學/生命科學院/分子與細胞生物學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202104321

摘要

不對稱細胞分裂是細胞分化的重要過程。借助合成生物學的概念，我們可以通過在對稱分裂的模式生物，如大腸桿菌，中實施核心的不對稱分裂調控網絡來重現該過程。先前，我們的研究中發現可以用新月柄桿菌中構築極性網絡的核心蛋白(PopZ)來建構最小的不對稱細胞分裂模型。PopZ會穩健的在大腸桿菌細胞中行成單一的極化點，並能在開啟下游的基因表達後藉由一個不會擴散的報導蛋白形成可視化的不對稱分模型，完成最小系統的建構。然而這個最小的不對稱性分裂系統對報導蛋白的表達水平波動很敏感，因此在這項研究中我們的目標是添加對向極的新系統來建立一個雙極的模型，以期建立一個更穩定的不對稱細胞分裂系統。此系統設計使用新月柄桿菌PodJ（另一種也在細胞極處自組織的支架蛋白）添加到先前的系統中，並利用一個PodJ 的結合蛋白(PleC)作為連接蛋白進行測試。本研究的結果表明，PodJ和PleC可以作為在大腸桿菌中重建的穩健不對稱細胞分裂的第二極。

關鍵字

不對稱細胞分裂 ； 新月柄桿菌 ； 細胞極化 ； 大腸桿菌 ； 最小系統

並列摘要

Asymmetric cell division is an important process for the cellular differentiation. With the concept of synthetic biology, we can recreate this process by implementing the core regulatory networks in symmetrically dividing model organisms, like Escherichia coli. Previously, we found that we can minimally reconstruct asymmetric cell division with PopZ, a scaffold protein in the central polarity pathway of Caulobacter crescentus, which acts as a robust single pole in E. coli that can turn on gene expression asymmetri-cally. With another layer that restricts diffusion of the downstream reporter, we can vir-tualize this asymmetric cell division model. The asymmetry of the minimal system, however, is sensitive to fluctuations in reporter protein level. In this study, we aim to establish a two-pole system that can add on to the pervious system using C. crescentus PodJ, another scaffold protein which also self-organizes at cell poles. PleC, a PodJ bind-ing protein, was tested as the adaptor. Results in this study suggest the possibility of us-ing PodJ and PleC as the second organizing pole for a robust asymmetric cell division reconstituted in E. coli.

並列關鍵字

asymmetric cell division ； Caulobacter crescentus ； cell polarization ； Escherichia coli ； minimal system

參考文獻

Abraham, W.-R., Strömpl, C., Meyer, H., Lindholst, S., Moore, E. R., Christ, R., Vancanneyt, M., Tindall, B. J., Bennasar, A., Smit, J., Tesar, M. (1999). Phylog-eny and polyphasic taxonomy of Caulobacter species. Proposal of Maricaulis gen. nov. with Maricaulis maris (Poindexter) comb. nov. as the type species, and emended description of the genera Brevundimonas and Caulobacter. International Journal of Systematic and Evolutionary Microbiology, 49(3), 1053–1073. https://doi.org/10.1099/00207713-49-3-1053

Aguilaniu, H., Gustafsson, L., Rigoulet, M., Nyström, T., (2003). Asymmetric Inher-itance of Oxidatively Damaged Proteins During Cytokinesis. Science, 299(5613), 1751–1753. https://doi.org/10.1126/science.1080418

Amos, M. (2014). Population-based microbial computing: a third wave of synthetic bi-ology? International Journal of General Systems, 43(7), 770–782. https://doi.org/10.1080/03081079.2014.921001

Anderson, J. C., Voigt, C. A., Arkin, A. P. (2007). Environmental signal integration by a modular AND gate. Molecular Systems Biology, 3(1), 133. https://doi.org/10.1038/msb4100173

Barák, I., Muchová, K., Labajová, N. (2019). Asymmetric cell division during Bacil-lus subtilis sporulation. Future Microbiology, 14(4), 353–363. https://doi.org/10.2217/fmb-2018-0338