生物DNA分子通常以A-T和G-C碱基配对的线性双螺旋形式而存在。但是，近年来发现DNA或RNA链上多个鸟嘌呤（G）或胞嘧啶（C）的重复出现可分别形成G-quadruplex（G4）或i-motif的二级结构，这些结构对于端粒DNA保护、DNA复制、基因转录及mRNA蛋白翻译等过程的表观遗传调控起着十分重要的作用。我们首次发现家蚕转录因子BmPOUM2基因启动子上具有可能的G4结构。项目将采用分子生物学、细胞生物学、发育生物学和生物信息学等方法，研究家蚕BmPOUM2启动子G4和i-motif高级结构的结构与功能。研究内容包括：1）BmPOUM2启动子高级结构的鉴定；2）该高级结构的分子和理化特征；3）该高级结构的调控蛋白；4）该高级结构的生物学功能；5）该高级结构的系统进化及生物学意义。研究将提出基因转录调控的一种全新的分子机制，对于深入认识生物基因调控机理具有重要的科学意义。

DNA molecules in cells usually exist in the form of linear double-stranded helix with A-T and G-C base pairs. However, it has been found recently that when runs of guanines or cytosines are presented in the chains of DNA or RNA, the secondary structures of G-guadruplex (G4) or i-motif can form. These structures are believed to play critical important roles for epigenetic regulation of telomeric DNA protection, DNA replication, gene transcription and mRNA protein stranslation. We for the first time found that the promoter of transcription factor BmPOUM2 in Bombyx mori contains potential G4 structure. This project will study the advanced structure of G4 and i-motif in the promoter of the transcriptiion factor BmPOUM2 in the silkworm by the appoaches of molecular biology, cell biology, development biology and bioinfomatics. The contents of the study include :1) Identification of the advanced structure of the promoter of BmPOUM2; 2) Molecular and Biochemical charaters of the advanced structure of the promoter of BmPOUM2; 3) Regulatory proteins of the advanced structure of the promoter of BmPOUM2; 4) Biological functions of the advanced structure of the promoter of BmPOUM2; and 5）Systemic evolution and biological significance of the advanced structure of the promoter of BmPOUM2. The study will provide a novel molecular mechanism of the regulation of gene transcription, which is significantly important for our understanding the mechanism of gene regulation in organisms.