Martín Guiomar
Department of Biology, Healthcare and the Environment, Faculty of Pharmacy and Food Sciences, University of Barcelona, Barcelona, Spain.
Front Plant Sci. 2023 Feb 10;14:1097127. doi: 10.3389/fpls.2023.1097127. eCollection 2023.
Retrograde signals sent by chloroplasts control transcription in the nucleus. These signals antagonistically converge with light signals to coordinate the expression of genes involved in chloroplast functioning and seedling development. Although significant advances have been made in understanding the molecular interplay between light and retrograde signals at the transcriptional level, little is known about their interconnection at the post-transcriptional level. By using different publicly available datasets, this study addresses the influence of retrograde signaling on alternative splicing and defines the molecular and biological functions of this regulation. These analyses revealed that alternative splicing mimics transcriptional responses triggered by retrograde signals at different levels. First, both molecular processes similarly depend on the chloroplast-localized pentatricopeptide-repeat protein GUN1 to modulate the nuclear transcriptome. Secondly, as described for transcriptional regulation, alternative splicing coupled with the nonsense-mediated decay pathway effectively downregulates expression of chloroplast proteins in response to retrograde signals. Finally, light signals were found to antagonistically control retrograde signaling-regulated splicing isoforms, which consequently generates opposite splicing outcomes that likely contribute to the opposite roles these signals play in controlling chloroplast functioning and seedling development.
叶绿体发出的逆行信号控制着细胞核中的转录。这些信号与光信号相互拮抗，共同协调参与叶绿体功能和幼苗发育的基因表达。尽管在转录水平上理解光信号与逆行信号之间的分子相互作用方面取得了重大进展，但在转录后水平上它们的相互联系却知之甚少。通过使用不同的公开可用数据集，本研究探讨了逆行信号对可变剪接的影响，并定义了这种调控的分子和生物学功能。这些分析表明，可变剪接在不同水平上模拟了逆行信号触发的转录反应。首先，这两个分子过程同样依赖于定位于叶绿体的五肽重复蛋白GUN1来调节核转录组。其次，如转录调控所述，可变剪接与无义介导的衰变途径相结合，可有效下调逆行信号响应下叶绿体蛋白的表达。最后，发现光信号可拮抗控制逆行信号调控的剪接异构体，从而产生相反的剪接结果，这可能有助于这些信号在控制叶绿体功能和幼苗发育中发挥相反的作用。
