酪氨酸羟化酶在BmNPV控制家蚕运动行为中的作用机制研究

BmNPV是一种杆状病毒，家蚕在感染BmNPV的后期会产生运动行为增强的现象，其原因是病毒以某种方式控制宿主行为从而促进自己的传播，此现象是病毒与宿主互作的典型案例。为阐明病毒控制宿主行为机制，在前期研究中，我们通过组学研究鉴定了控制宿主行为的关键因子——多巴胺，其在家蚕运动行为能力增强过程中发生了显著上调，而负责合成多巴胺的限速酶——酪氨酸羟化酶在病毒感染后期也显著增加。个体实验结果表明，注射酪氨酸羟化酶抑制剂可有效的抑制病毒引起的运动行为增强的现象。基于以上结果，本项目拟开展工作主要包括：1）利用可调控的转基因操控系统，进一步证实酪氨酸羟化酶及多巴胺在行为机制中的关键性作用； 2）研究酪氨酸羟化酶调控方式，分析磷酸化对其活性的影响，鉴定其磷酸化的关键作用位点；3）鉴定酪氨酸羟化酶上游分子，构建病毒——酪氨酸羟化酶——多巴胺信号通路，阐明酪氨酸羟化酶途径在增强家蚕运动行为中的关键作用。

BmNPV is one of nuclear polyhedrosis virus, which normally paratisize silkworm as their host. When silkworm are affected by BmNPV, enhanced locomotory behaviors will occur at the end of the larval stage. People think that the virus induces this behavior so that, after death, the decaying cadaver will contaminate a larger surface area resulting in increased dispersal and transmission of the virus. This is a representative phenomenon of interaction between virus and host. In order to clarify the mechanism of enhanced locomotory behaviors of silkworm by BmNPV, in our previous study, the key factor of dopamine was identified by omics tools, which were accumulated in the process of enhanced locomotory behaviors. From the transcriptional analysis, we found that the tyrosine hydroxylase, which is responsible for the synthetizing the dopamine, was up-regulated in these process. Furthermore, when the inhibitor of tyrosine hydroxylase was injected into the silkworm affect by BmNPV, the enhanced locomotory behaviors were reduced significantly. Based on these results, some experiments will be performed in order to verify the key role of tyrosine hydroxylase in the enhanced locomotory behaviors by BmNPV. 1) The operable transgenic tools will be employed to certify the role of tyrosine hydroxylase in signaling pathway during the enhanced locomotory behaviors of silkworm affected by BmNPV. 2) Phosphorylation of tyrosine hydroxylase will be investigated and analyzed in vitro and vivo in silkworm. The crucial sites of amino acid of tyrosine hydroxylase will be studied and identified. 3) The up-stream factor in the signaling pathway of virus-dopamine-tyrosine hydroxylase will be investigated and studied. The result will give us a comprehensive understand for the mechanism of enhanced locomotory behaviors of silkworm affected by BmNPV.