JNK/p38 MAPK信号通路在棉铃虫响应UV胁迫机制中的作用

Ultraviolet light irradiation is regarded as an environmental stress factor to insects, and can induce various physiological and biochemical changes. In our previous study, we observed that mitogen-activated protein kinase (MAPK) was up-regulated after UV light irradiation in H.armigera adults. Does this mean that MAPK cascade is involved in the signal transduction in response to UV light stress in insects? However, to our knowledge there is no published data regarding the signal transduction of the insect responsing to UV light stress. JNK and p38 MAPK both belong to stress activated protein kinases, and could be activated by UV light, heat shock and osmotic stress and so on. In this project, we will clone the full-length cDNA of JNK and p38 MAPK, and then analyse their expression under UV light stress. Also the role of JNK and p38 MAPK pathway responsing to UV light stress will be studied by RNAi. The results will help us to well understand the signal transduction pathway of insects to the stress of UV light and further study the molecular mechanism of insects responsive to UV light stress.

紫外线（Ultraviolet light，UV）对昆虫而言是一种胁迫因子，能引起昆虫一系列的生理生化响应。在前期研究中，项目申请人发现棉铃虫成虫的丝裂原活化蛋白激酶（MAPK）在UV照射后表达量上调。这是否意味着MAPK信号通路参与了昆虫响应UV胁迫的信号传导？综观国内外近几十年的研究，均未见这方面的报道。JNK和p38 MAPK均属于MAPK家族信号通路中的关键蛋白激酶，能够被紫外线、高温、渗透压等胁迫因子激活。鉴于此，本项目以趋光昆虫棉铃虫为材料，克隆JNK和p38 MAPK基因，研究UV照射对棉铃虫JNK和p38 MAPK基因表达的影响，利用RNAi技术验证JNK和p38 MAPK信号通路在棉铃虫响应UV胁迫机制中的作用。研究结果不仅对揭示昆虫响应UV胁迫的信号传导有重要意义，并为进一步探索昆虫响应UV胁迫的分子机制奠定基础。

紫外线一种环境胁迫因子，能引起昆虫一系列的生理生化响应。在前期研究中，项目申请人发现棉铃虫成虫的丝裂原活化蛋白激酶（MAPK）在UV照射后表达量上调。这是否意味着MAPK信号通路参与了昆虫响应UV胁迫的信号传导？综观国内外近几十年的研究，尚未见报道。本项目以趋光昆虫棉铃虫为材料开展研究，获得结果如下：（1）JNK基因的cDNA全长为1191个碱基，编码396个氨基酸，编码蛋白的相对分子量为49.19kDa，等电点为10.75；p38 MAPK基因的cDNA全长为1083个碱基，编码360个氨基酸，编码蛋白的相对分子量为41.51 kDa，等电点为6.18。（2）实时荧光定量PCR结果表明：随着UV照射时间的延长，JNK和p38 MAPK基因的表达量表现出先增加后降低的趋势；照射时间在60min时，棉铃虫体内的JNK基因和p38 MAPK的表达量最高；在照射60 min、90 min和120 min时棉铃虫JNK基因的诱导表达量显著高于对照组；在照射60 min、120 min和150 min时棉铃虫38 MAPK基因的诱导表达量显著高于对照组。（3）分别沉默JNK和p38 MAPK基因的表达后，棉铃虫抗氧化酶SOD、CAT、POX、GST活性对UV胁迫的响应显著降低。本研究研究发现了JNK和p38 MAPK信号通路在棉铃虫响应UV胁迫机制中的作用。研究结果不仅对揭示昆虫响应UV胁迫的信号传导有重要意义，并为进一步探索昆虫响应UV胁迫的分子机制奠定基础。