The "RNA world" represents a novel frontier for the study of fundamental biological processes and human diseases and is paving the way for the development of new drugs tailored to the patient's biomolecular characteristics. Although scientific data about coding and non-coding RNA molecules are continuously produced and available from public repositories, they are scattered across different databases and a centralized, uniform, and semantically consistent representation of the "RNA world" is still lacking. We propose RNA-KG, a knowledge graph encompassing biological knowledge about RNAs gathered from more than 50 public databases, integrating functional relationships with genes, proteins, and chemicals and ontologically grounded biomedical concepts. To develop RNA-KG, we first identified, pre-processed, and characterized each data source; next, we built a meta-graph that provides an ontological description of the KG by representing all the bio-molecular entities and medical concepts of interest in this domain, as well as the types of interactions connecting them. Finally, we leveraged an instance-based semantically abstracted knowledge model to specify the ontological alignment according to which RNA-KG was generated. RNA-KG can be downloaded in different formats and also queried by a SPARQL endpoint. A thorough topological analysis of the resulting heterogeneous graph provides further insights into the characteristics of the "RNA world". RNA-KG can be both directly explored and visualized, and/or analyzed by applying computational methods to infer bio-medical knowledge from its heterogeneous nodes and edges. The resource can be easily updated with new experimental data, and specific views of the overall KG can be extracted according to the bio-medical problem to be studied.

翻译：“RNA世界”是研究基本生物学过程和人类疾病的前沿领域，并为开发针对患者生物分子特征的个性化新药铺平道路。尽管关于编码和非编码RNA分子的科学数据持续产生并可从公共存储库获取，但这些数据分散在不同数据库中，目前仍缺乏一个集中化、统一且语义一致的“RNA世界”表征。我们提出RNA-KG这一知识图谱，整合了来自50多个公共数据库的RNA生物学知识，融合了与基因、蛋白质和小分子的功能关系以及基于本体的生物医学概念。为构建RNA-KG，我们首先识别、预处理并表征了每个数据源；随后构建了一个元图谱，通过描述该领域中所有感兴趣的生物分子实体和医学概念及连接它们的交互类型，提供了本体的KG描述。最后，我们利用基于实例的语义抽象知识模型，指定了生成RNA-KG的本体对齐方式。RNA-KG支持以多种格式下载，并可通过SPARQL端点查询。对生成的异构图进行拓扑分析，可进一步揭示“RNA世界”的特征。RNA-KG既可被直接探索和可视化，也可通过计算方法分析其异质性节点和边以推断生物医学知识。该资源可轻松更新新实验数据，并根据待研究的生物医学问题提取KG的特定视图。