巨细胞病毒MIE基因的体内组织特异性剪接机制研究

Cytomegalovirus (CMV) is one of the most infectious agents causing birth defects. Congenital CMV infection results in neonatal death or other clinical sequelea including sensorineural hearing loss, vision loss, and mental retardation. Our recent studies discovered that there exist differences in the CMV replication mode and CMV pathogenicity among different tissues, and that MIE gene splicing is essential for CMV replication. However，it is not clear how the MIE gene splicing is specifically controlled in different tissues. Our previous studies revealed that the splicing regulation of MIE gene differs in cells from different tissues, and that two polypyrimidines in the intron 4 is critical for MIE gene expression skipping from IE1 to IE2. These discoveries suggest that MIE gene splicing is tissue-specific and may be related to the pathogenicity of CMV. In this project, we will 1) investigate the splicing and expression of MIE gene in different organs or tissues using a transgenic mouse model, and 2) analyze the effects of MIE gene products on the different organs of mice. It is our expectation that several cis- and trans-elements will be identified to facilitate tissue-specific splicing of MIE gene. The outcomes from this proposed research is expected to result in an evaluation of the potential of the splicing regulation as a target for anti-CMV infection. The results of our investigation into mechanisms of MIE gene tissue-specific splicing will provide insight into development of a novel strategy in prevention and/or treatment of CMV-caused diseases.

巨细胞病毒（CMV）感染是导致新生儿出生缺陷最主要的感染性因素，会导致新生儿神经性耳聋、视力丧失、智力低下等，目前暂无防治的疫苗和特效药物。CMV在不同器官中的复制速度及致病性存在差异，而CMV的主要IE（MIE）基因的剪接对病毒复制至关重要，目前尚无关于MIE基因组织特异性剪接的研究报导。在前期工作中本课题组确定两处MIE基因剪接的关键位点，同时发现在不同细胞中MIE基因的表达存在差异，提示MIE基因剪接存在组织特异性，并且可能与CMV的致病性有关。本项目拟借助转基因小鼠研究MIE基因在不同器官中的剪接、表达情况，以及对小鼠器官发育和功能的影响，分析剪接的关键位点及相关蛋白。评估剪接位点成为抗CMV感染药物靶标的潜力，以期为MIE基因剪接机制的进一步研究奠定理论基础，为特异性的抵抗和治疗CMV感染提供新的策略和科学依据。

巨细胞病毒（CMV）感染是导致新生儿出生缺陷最主要的感染性因素，会导致新生儿神经性耳聋、视力丧失、智力低下等，目前暂无防治的疫苗和特效药物。本项目探究了CMV的主要IE（MIE）基因在小鼠体内组织特异性剪接的情况，及其对病毒复制的影响。主要成果包括以下两方面：（1）基于小鼠模型揭示了CMV的MIE基因在小动物体内不同器官组织剪接的差异；（2）揭示了CMV感染后在不同器官复制水平的差异，验证了恩替卡韦对病毒感染有一定的治疗效果。本项目首次验证了MIE基因在不同组织中的剪接差异，为CMV感染和复制的组织特异性提供了一种解释； 在细胞水平验证了CMV的IE1表达可以保护PML不被I型单纯疱疹病毒的ICP0降解，同时为CMV感染治疗提供了一种药物选择恩替卡韦，作为更昔洛韦治疗的补充。为特异性抵抗和治疗CMV感染提供科学依据和理论补充。