阿拉伯芥熱休克因子HSFC1在溫度逆境下的表達調控

Expression Regulation of Arabidopsis Heat Shock Factor HSFC1 under Temperature Stress

張凌誌(Ling-Chih Chang)

指導教授 ： 靳宗洛

國立臺灣大學/生命科學院/植物科學研究所/碩士(2021年)

https://doi.org/10.6342/NTU202101271

摘要

熱休克轉錄因子參與了其下游逆境相關基因的調控，這些基因的表現能促進植物在逆境條件下的存活。阿拉伯芥有21個熱休克轉錄因子基因，它們主要參與在對熱以及其他非生物和生物逆境的反應。其中，熱休克轉錄因子C1（HSFC1）的功能與調控仍有待研究。我們先前的研究結果顯示，HSFC1的基因表現會受到冷逆境、ABA和NaCl處理誘導。在種子萌芽試驗中，過量表現HSFC1 mRNA的轉植株提高對ABA和NaCl的敏感性。研究證實，mRNA轉譯起始點上游的開放閱讀框（uORF）以及長鏈非編碼核糖核酸（lncRNA）會影響轉錄後的調控，對植物之發育和適應環境變化扮演重要角色。本論文的結果顯示，在HSFC1 mRNA 5’端的非轉譯區（5'UTR）中具有2個uORFs，通過暫時性表現的實驗結果，我們發現uORF2可能對HSFC1 mRNA的轉譯具有正向調控的作用。此外，在HSFC1 mRNA的反向股發現了lncRNA，命名為asHSFC1。實驗結果顯示，在冷逆境和ABA處理下asHSFC1的轉錄量多寡，能影響HSFC1 mRNA的轉錄量。同時，利用能調控熱感應性之主要熱休克轉錄因子HSFA1s的缺失株中，發現HSFC1以及asHSFC1的轉錄表現量在熱及冷逆境下受到顯著的影響，顯示HSFC1以及asHSFC1可能會參與熱休克訊號傳遞路徑之中。總結來說，HSFC1 mRNA的uORF2可能對HSFC1的轉譯有正向的調節作用，在非生物逆境下asHSFC1的轉錄量多寡可能會影響HSFC1的轉錄量，同時HSFC1也可能被適當的熱休克反應所需要。

關鍵字

阿拉伯芥 ； 熱休克轉錄因子C1 ； 反向股熱休克轉錄因子C1 ； 上游開放閱讀框 ； 長鏈非編碼核糖核酸 ； 非生物逆境反應 ； 轉錄後調控

並列摘要

Heat shock factors (HSFs) are involved in the regulation of their downstream stress-associated genes that function to facilitate plant survival under stressful conditions. In Arabidopsis, there are 21 HSFs and mainly involved in the activation of genes in response to heat as well as to various abiotic and biotic stresses. However, the function and regulation of HSFC1 remain to be elucidated. Our previous studies showed that the expression level of HSFC1 was significantly induced by cold stress, ABA, and NaCl treatments. The HSFC1-overexpression lines were more sensitive to ABA and NaCl than the wild-type plants during seed germination. It has been known that the upstream open reading frames (uORFs) and long non-coding RNA (lncRNA) are regulators of mRNA translation in response to developmental and environmental cues. There are 2 uORFs found in the 5'-UTR region of HSFC1 mRNA and the uORF2 significantly promoted HSFC1 translation in a trans-activation assay. Moreover, the transcript level of HSFC1 anti-sense lncRNA, asHSFC1, influences the mRNA level of HSFC1 under 4°C cold and ABA treatments. The class-A HSFA1 (a, b, d, e) not only play the important role in thermotolerance but involve in plant growth and development and response to other abiotic stresses. By using the HSFA1s mutation plants, the transcript level of HSFC1 and asHSFC1 were significantly affected in response to heat and cold treatments, which suggested that HSFC1 and asHSFC1 may participate in heat shock signaling pathway. In conclusion, our results highlighted that the uORF2 of HSFC1 plays a positive role for HSFC1 translation, the transcriptional level of asHSFC1 influences the mRNA levels of HSFC1 under abiotic stress, and HSFC1 is required for proper heat shock response.

並列關鍵字

Arabidopsis ； HSFC1 ； asHSFC1 ； uORF ； lncRNA ； abiotic stress response ； post-transcriptional control

參考文獻

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