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Overlapping genes are widely prevalent; however, their expression and consequences are poorly understood. Here, we describe and functionally characterize a novel zyx-1 overlapping gene, azyx-1, with distinct regulatory functions in Caenorhabditis elegans. We observed conservation of alternative open reading frames (ORFs) overlapping the 5′ region of zyxin family members in several animal species, and find shared sites of azyx-1 and zyxin proteoform expression in C. elegans. In line with a standard ribosome scanning model, our results support cis regulation of zyx-1 long isoform(s) by upstream initiating azyx-1a. Moreover, we report on a rare observation of trans regulation of zyx-1 by azyx-1, with evidence of increased ZYX-1 upon azyx-1 overexpression. Our results suggest a dual role for azyx-1 in influencing zyx-1 proteoform heterogeneity and highlight its impact on C. elegans muscular integrity and locomotion.

重叠基因广泛存在，但目前对其表达模式与生物学效应的认知仍较为匮乏。本研究针对秀丽隐杆线虫（Caenorhabditis elegans）中一种全新的、与zyx-1基因重叠的azyx-1基因进行了系统描述与功能表征，该基因具备独特的调控功能。我们在多个动物物种中均发现，斑联蛋白家族（zyxin family）成员的5'端区域存在重叠的可变开放阅读框（alternative open reading frames, ORFs），并在秀丽隐杆线虫中观察到azyx-1与zyx-1的蛋白变体（proteoform）共享表达位点。结合经典的核糖体扫描模型（ribosome scanning model），本研究结果证实，上游起始的azyx-1a可对zyx-1长亚型产生顺式调控作用。此外，我们还罕见地观测到azyx-1对zyx-1的反式调控现象，实验证据表明，当azyx-1过表达时，ZYX-1的蛋白水平显著上调。本研究结果提示，azyx-1可通过双重作用模式影响zyx-1的蛋白变体异质性，并凸显了该基因对秀丽隐杆线虫肌肉完整性与运动能力的关键调控作用。