酵母细胞中鞘脂LCB调节mRNA降解机制的研究

mRNA decay is one of control of eukaryotic gene expression. It is still not clear how the basal rate of mRNA decay is control or how the decay rate is adjusted in response to environmental changes or under stress. Our published paper showed that Pkh1/2-Pkc1 controled mRNA decay. In yeast sphingolipid LCBs are the only known activators of Pkh1/2, Our previous data showed that myriocin, which can limit biosynthesis of sphingolipid, control mRNA degradation. Besides, several enzymes which are proved be related to mRNA degradation are sensitive to myriocin. Based upon our preliminary studies we hypothesize that the sphingolipid LCBs regulate basal mRNA decay under stess. We try to elucidate how sphinglipid LCB regulates mRNA decay under stress by studies three aims:1. To demonstrate the mRNA decay is regulated by sphingolipid LCB. 2. To determine if Pkh1/2-Pkc1 works downsream of LCBs in mRNA degraduation.3. To determine if sphingolipid LCBs regualte Ccr4-Pop2-Not and Pan2-Pan3 deadenylase activity. In a word, our purpose is to establise the signaling pathway of sphingolipid pathway in regulating mRNA decay.

在应激等环境改变调节下，真核生物可启动基因表达调控使生物体适应环境生长生存，mRNA降解是表达调控重要手段。前期我们证明在热或营养物耗尽等条件下，Pkh1/2-Pkc1影响mRNA降解，已知鞘脂LCB是Pkh1/2唯一激活剂，鞘脂合成抑制后mRNA降解时间延长。此外，mRNA降解过程中的多个酶对鞘脂合成抑制剂myriocin敏感。所以推测鞘脂可能参与mRNA降解调节。本课题以热或营养物耗尽等应激为诱发因素，用药物抑制剂或构建突变体等处理措施，采用Northern Bolt、酶活性检测等手段，研究1.鞘脂LCB是否调节mRNA降解2.鞘脂调节mRNA降解是否通过Pkh1/2-Pkc1途径3.鞘脂是否影响脱尾酶活性。目的是探讨鞘脂LCB信号参与mRNA降解的调控机制，对阐明哺乳动物细胞mRNA降解调控和micRNA作用机制有重要意义。

在应激等环境改变调节下，真核生物可启动基因表达调控使生物体适应环境生长生存，mRNA降解是表达调控重要手段。在热或营养物耗尽等条件下，Pkh1/2-Pkc1影响mRNA降解。由于鞘脂LCB是Pkh1/2唯一激活剂，鞘脂合成抑制后mRNA降解时间延长，mRNA降解过程中的多个酶对鞘脂合成抑制剂myriocin敏感。所以我们推测鞘脂可能参与mRNA降解调节。.本课题以热或营养物耗尽等应激为诱发因素，用药物抑制剂或构建突变体等处理措施，采用Northern Blot、酶活性检测等手段，对其鞘脂LCB如何调节mRNA降解的机制进行研究和探讨。我们明确了鞘脂LCB在mRNA的降解中的作用，研究了鞘脂LCB是否通过Pkh1/2影响mRNA降解，并进一步探索了Pkc1调节mRNA降解的分子机制。此外，还对鞘脂是否通过胞吐在mRNA降解中发挥作用进行了探讨。.通过本项目的顺利开展，我们首先确认了鞘脂通过Pkh1/2-Pkc1途径调节mRNA降解；其次我们发现Pkc1是通过影响脱尾酶活性进而调节mRNA降解，并可能是通过磷酸化Pab1来实现的。此外，我们还发现，LCB1可能通过调控胞吐进而影响mRNA的降解。.本项目明确了鞘脂LCB信号参与mRNA降解的调控机制，对阐明哺乳动物细胞mRNA降解调控和micRNA作用机制有重要意义。