A major part of the transcriptome complexity is attributed to multiple types of DNA or RNA fusion events, which take place within a gene such as alternative splicing or between different genes such as DNA rearrangement and trans-splicing. In the present study, using the RNA deep sequencing data, we systematically survey a type of non-canonical fusions between the RNA transcripts from the two opposite DNA strands. We name the products of such fusion events cross-strand chimeric RNA (cscRNA). Hundreds to thousands of cscRNAs can be found in human normal tissues, primary cells, and cancerous cells, and in other species as well. Although cscRNAs exhibit strong tissue-specificity, our analysis identifies thousands of recurrent cscRNAs found in multiple different samples. cscRNAs are mostly originated from convergent transcriptions of the annotated genes and their anti-sense DNA. The machinery of cscRNA biogenesis is unclear, but the cross-strand junction events show some features related to RNA splicing. The present study is a comprehensive survey of the non-canonical cross-strand RNA junction events, a resource for further characterization of the originations and functions of the cscRNAs.

转录组复杂性的主要部分归因于多种类型的 DNA 或 RNA 融合事件，这些事件发生在一个基因内，例如可变剪接或不同基因之间，例如 DNA 重排和反式剪接。在本研究中，使用 RNA 深度测序数据，我们系统地调查了来自两条相反 DNA 链的 RNA 转录物之间的一种非规范融合。我们将此类融合事件的产物命名为跨链嵌合 RNA (cscRNA)。在人类正常组织、原代细胞和癌细胞以及其他物种中可以发现成百上千的 cscRNA。尽管 cscRNA 表现出很强的组织特异性，但我们的分析确定了在多个不同样本中发现的数以千计的复发 cscRNA。cscRNA 主要来源于注释基因及其反义 DNA 的会聚转录。cscRNA 生物发生的机制尚不清楚，但交叉链连接事件显示出一些与 RNA 剪接相关的特征。本研究是对非规范交叉链 RNA 连接事件的全面调查，这是进一步表征 cscRNA 起源和功能的资源。