Pseudoexon (PE) inclusion has been implicated in various dystrophinopathies; however, its splicing characteristics have not been fully investigated. This study aims to analyze the splicing characteristics of dystrophin PEs and compare them with those of dystrophin canonical exons (CEs). Forty-two reported dystrophin PEs were divided into a splice site (ss) group and a splicing regulatory element (SRE) group. Five dystrophin PEs with characteristics of poison exons were identified and categorized as the possible poison exon group. The comparative analysis of each essential splicing signal among different groups of dystrophin PEs and dystrophin CEs revealed that the possible poison exon group had a stronger 3′ ss compared to any other group. As for auxiliary SREs, different groups of dystrophin PEs were found to have a smaller density of diverse types of exonic splicing enhancers and a higher density of several types of exonic splicing silencers compared to dystrophin CEs. In addition, the possible poison exon group had a smaller density of 3′ ss intronic splicing silencers compared to dystrophin CEs. To our knowledge, our findings indicate for the first time that poison exons might exist in DMD (the dystrophin gene) and present with different splicing characteristics than other dystrophin PEs and CEs.

中文翻译：

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DMD基因中抗肌萎缩蛋白假外显子的剪接特征及新型致病性内含子变异体的鉴定

假外显子 (PE) 包含与各种肌营养不良症有关。然而，其剪接特性尚未得到充分研究。本研究旨在分析抗肌萎缩蛋白PEs的剪接特征，并将其与抗肌萎缩蛋白经典外显子（CEs）的剪接特征进行比较。42 个报道的肌营养不良蛋白 PE 分为剪接位点 (ss) 组和剪接调节元件 (SRE) 组。鉴定出五个具有毒外显子特征的肌营养不良蛋白 PE 并将其归类为可能的毒外显子组。对不同组的dystrophin PEs和dystrophin CEs的每个基本剪接信号的比较分析表明，与任何其他组相比，可能有毒外显子组具有更强的3'ss。至于辅助 SRE，与肌营养不良蛋白 CE 相比，发现不同组的肌营养不良蛋白 PE 具有更小密度的不同类型的外显子剪接增强子和更高密度的几种类型的外显子剪接消音器。此外，与抗肌萎缩蛋白 CE 相比，可能有毒外显子组的 3' ss 内含子剪接消音器密度较小。据我们所知，我们的研究结果首次表明 DMD（肌营养不良蛋白基因）中可能存在毒物外显子，并且呈现出与其他肌营养不良蛋白 PE 和 CE 不同的剪接特征。