基于猪生殖系统研究嵌合RNA的形成新机制及其繁殖调控功能

Chimeric RNAs are fused by two previously separate genes located on different genomic loci. As diagnostic markers and drug targets, chimeric RNAs show a broad clinical application. Despite great advances,the fusion mechanism remains to be elucidated, and the chimeric RNA world also remains largely uncharted with regard to the physiological function of these molecules in the field of animal breeding and reproduction, and uncovering the function of the individual chimeric RNA is challenging. Previously, we identified a lot of chimeric RNAs associated with reproduction by performing transcriptome sequencing on 11 pigs. The precursor genes contained the consensus sequences involved in chromosomal contacting. DNA motifs were found in the promoter regions of some precursor genes, suggesting that the precursor genes would be co-regulated by similar transcription factors. We speculated that chromosomal interactions and gene co-transcriptions were the prerequisites for the formation of chimeric RNAs. Furthermore, we hypothesized that the precursor genes were co-localized to the shared transcription factory and transcribed into primary transcripts, and then were processed to form chimeric RNAs. We will verify this hypothesis by FISH and chromosome conformation capturing, and will research chimeric RNAs in the regulation of reproductive function by the forward and reverse genetic strategies. The present study will reveal the places, conditions, and some factors for the formation of chimeric RNAs, and will represent a new mechanism for gene fusion. Results will aid in the further understanding of chimeric RNAs in the regulation of reproductive function of pig.

嵌合RNA是由两个或以上的独立基因（即亲本基因）融合而成的新基因，作为诊断标记和药物靶标具有良好的应用前景，但其形成机制仍有争议，且在动物遗传繁育领域的研究及应用尚少。本组前期对11头猪分别进行了转录组测序,鉴定了大量与生殖功能相关的嵌合RNA，发现一对亲本基因含有可介导染色体空间互作的模式序列，其启动子区存在共转录条件。我们推测染色体互作和基因共转录是嵌合RNA形成的前提条件，提出"亲本基因通过转录工厂共享机制形成嵌合RNA"的新模型。我们拟利用FISH技术、染色体构象捕获技术等方法证明模型，利用正向和反向遗传策略研究嵌合RNA的生殖调控功能。此研究将阐明嵌合RNA形成的场所、条件和部分参与因子，从细胞和分子水平揭示嵌合RNA的形成新机制，为猪生殖调控的研究提供新标记和新途径。

嵌合基因通过连接不同基因的功能域，可改变原（亲本）基因的功能，增加转录组和蛋白质组的多样性和复杂性。将嵌合基因研究融入到动物遗传繁育中，有利于挖掘中国地方猪品种特有的基因资源信息，丰富分子育种理论基础，是深入解析猪繁殖性状及遗传特性的潜在途径之一。.本项目建立了1套嵌合基因鉴定及分析技术体系，获得4项软件著作权，得到1007个猪的高质量嵌合基因；通过猪肝脏、睾丸、子宫内膜等多种组织的转录组数据，构建了针对特异组织及跨组织的基因共表达调控网络，深入研究了嵌合基因的功能及形成机制。本研究进一步提出了“嵌合基因的网络桥梁”效应，发现嵌合基因可加强亲本基因与其他基因的联系，缩短亲本基因及邻居节点的网络空间距离，紧凑局部拓扑结构，形成新的反馈调节通路。此外，通过项目实施，出版专著1部，申请专利1项；培养博士后1名、硕士毕业生3名、在读4名；项目成员中，1人次获中华农业科技奖创新团队奖，1人次获中国农业科学院优秀博士后称号，1人次获国家留学基金委资助访学，2人次入选石河子大学青年骨干教师培养计划，1人次入选石河子大学青年教师与对口支援高校名师“结对子”培养计划。.本项目对基因的嵌合形式、及其对原亲本基因所参与信号通路的影响规律的相关研究，丰富了嵌合基因的基础理论。另外，“嵌合基因的网络桥梁效应”模型可在复杂网络科学中建立一个生物分子网络演化的典型范例，有助于促进相关研究的交叉和进步。本项目研究总结的基因嵌合规律，可为人工基因编辑提供启示，优化相关基因工程环节。