利用小白鼠結締組織細胞株探討小白鼠分泌性蛋白24p3之生理特性

Functional study of secreted 24p3 protein via mouse connective tissue cell line L929

李倍慈(Pei-Tzu Li)

指導教授 ： 朱善德

國立臺灣大學/生命科學院/生化科學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.10125

摘要

小白鼠子宮能分泌24p3醣蛋白，在過去的研究中發現血球、纖維母細胞及肝細胞受IL-6、TNF-a、glucocorticoid、LPS及松節油等刺激後可誘導24p3蛋白質的生成，推測24p3蛋白質於發炎反應、壓力環境中及細胞凋亡過程扮演相當重要的角色，但真正之生理弁鄖疇憬

關鍵字

小白鼠分泌性蛋白24p3

並列摘要

24p3 protein is a secreted glycoprotein, which is estrogen-dependently expressed in mouse uterus, but is constitutively expressed in epididymis. The protein could associate with sperm head and enhance the sperm motility, and was also suggested as a stressor, apoptotic factor or inflammatory factor in blood cells, the function is not clear yet. Using mouse connective tissue cell line L929as a model, we are going to elucidate the reaction mechanism of 24p3 protein on the cells. First of all, dexamethasone could induce the 24p3 gene expression and protein secretion in this cell line, which suggested the existing of autocrine mechanism of 24p3 protein. According to the fluorescence microscopy observation, 24p3 protein could internalize into the cell in temperature-dependent status. Upon the internalization of the 24p3 protein into the cell, the intracellular level of ROS would be increased and the intracellualr level of GSH be decreased at beginning for protecting the cells and then be regenerated before 48 hours. Thereafter, the intracellular biochemical events would be triggered for responsive to the stress, including the changes of Bcl-2 and Bax ratio, DNA synthesis and p53 protein translocation. Incubation of the L929 cells with 10 mM 24p3 protein for 72 hours, the cell cycle would be arrested at S phase and the obvious DNA synthesis increase would be observed in 24p3 protein treated-cell via BrdU assay. At the same time, the mRNA expression ratio of Bcl-2/Bax decreased and cell viability could be reduced significantly. Besides, the translocation of p53 protein from cytosol to nuclei could be observed with fluorescence microscopy via FITC-labeled antibody, and it also suggested the increment of p53 protein synthesis. All of these may trigger by the 24p3 protein internalization to elevate the level of ROS in cytosol, which keeps the cell under stress then undergo the apoptosis. Further study is needed to elucidate the complicated mechanism.

並列關鍵字

24p3 protein

參考文獻

2. Davis TR, Tabatabai L, Bruns K, Hamilton RT, Nilsen-Hamilton M. 1991. Basic fibroblast growth factor induces 3T3 fibroblasts to synthesize and secrete a cyclophilin-like protein β2-microglobulin. Biochim Biophys Acta 1095:145-152.

3. Liu Q, Nilson-Hamiltom M. 1995. Identification of a new acute phase protein. J Biol Chem 270:22565-22570.

5. Flower DR, North ACT, Attwood TK. 1991. Mouse oncogene protein 24p3 is a member of the lipocalin protein family. Biochem Biophys Res Commun 180:69-74.

6. Flower DR. 1996. The lipocalin protein family：structure and function. Biochem. J. 318:1-14.

7. Goodman DS. 1980. Plasma retinol-binding protein. Annals of the New York Academy of Sciences. 348:378-390.