核醣核酸聚合酶第四次單元RPB4在轉錄及訊息核醣核酸降解過程之功能分析

Functional Characterization of RNA Polymerase II Subunit RPB4 in Transcription and mRNA Decay Machinery

簡如一(Ju-Yi Chien)

指導教授 ： 張瀞仁

國立臺灣大學/生命科學院/生化科學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02074

摘要

無資料

關鍵字

核醣核酸聚合酶轉錄 ； 處理體 ； 核醣核酸降解 ； 訊息核醣核酸代謝

並列摘要

Gene expression involves several distinct stages, which are tightly controlled and coordinated. Although the detailed mechanism of each stage is well established, we are still lacking the linkage of how different processes are connected. In Saccharomyces cerevisiae, Rpb4p, which was discovered as a RNA polymerase subunit, is reported to involve in mRNA processing, mRNA export, translation and mRNA degradation, suggesting a role of coordinator. In this study, we aimed to explore the functional characters of RPB4 in both transcription and mRNA degradation in mammalian system. We found that RPB4 located at P-bodies, which accommodate translationally repressed mRNPs and proteins involved in mRNA degradation. In addition, RPB4 interacted with DCP1a, DCP2, DDX6, EDC3 and CAF1a in RNA-independent manner. By tethering RPB4 to luciferase reporter mRNA, we further provided evidences that RPB4 is functionally related to mRNA decay machinery. Interestingly, we observed that RPB4 can translocate from cytoplasm to nucleus and associate with phosporylated RNA polymerase II in response to heat shock stress. Knockdown of RPB4 resulted in down-regulation of proteins involved in mRNA metabolism. Taken together, these findings imply that RPB4 might modulate specific class mRNAs’ turnover by coordinating their metabolic processes.

並列關鍵字

RNA polymerase II ； transcription ； P-body ； mRNA decay ； mRNA meatabolism

參考文獻

2. Cramer, P., et al., Architecture of RNA polymerase II and implications for the transcription mechanism. Science, 2000. 288(5466): p. 640-9.

3. Minakhin, L., et al., Bacterial RNA polymerase subunit omega and eukaryotic RNA polymerase subunit RPB6 are sequence, structural, and functional homologs and promote RNA polymerase assembly. Proc Natl Acad Sci U S A, 2001. 98(3): p. 892-7.

5. Woychik, N.A. and R.A. Young, RNA polymerase II subunit RPB4 is essential for high- and low-temperature yeast cell growth. Mol Cell Biol, 1989. 9(7): p. 2854-9.

6. Woychik, N.A., W.S. Lane, and R.A. Young, Yeast RNA polymerase II subunit RPB9 is essential for growth at temperature extremes. J Biol Chem, 1991. 266(28): p. 19053-5.

8. Miyao, T., J.D. Barnett, and N.A. Woychik, Deletion of the RNA polymerase subunit RPB4 acts as a global, not stress-specific, shut-off switch for RNA polymerase II transcription at high temperatures. J Biol Chem, 2001. 276(49): p. 46408-13.