Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712.
The Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX 78712.
Proc Natl Acad Sci U S A. 2022 Nov;119(44):e2214565119. doi: 10.1073/pnas.2214565119. Epub 2022 Oct 25.
Light signals perceived by a group of photoreceptors have profound effects on the physiology, growth, and development of plants. The red/far-red light-absorbing phytochromes (phys) modulate these aspects by intricately regulating gene expression at multiple levels. Here, we report the identification and functional characterization of an RNA-binding splicing factor, SWAP1 (SUPPRESSOR-OF-WHITE-APRICOT/SURP RNA-BINDING DOMAIN-CONTAINING PROTEIN1). Loss-of-function mutant is hyposensitive to red light and exhibits a day length-independent early flowering phenotype. SWAP1 physically interacts with two other splicing factors, (SFPS) SPLICING FACTOR FOR PHYTOCHROME SIGNALING and (RRC1) REDUCED RED LIGHT RESPONSES IN CRY1CRY2 BACKGROUND 1 in a light-independent manner and forms a ternary complex. In addition, SWAP1 physically interacts with photoactivated phyB and colocalizes with nuclear phyB photobodies. Phenotypic analyses show that the , and double mutants display hypocotyl lengths similar to that of the respective single mutants under red light, suggesting that they function in the same genetic pathway. The double and triple mutants display pleiotropic phenotypes, including sterility at the adult stage. Deep RNA sequencing (RNA-seq) analyses show that SWAP1 regulates the gene expression and pre-messenger RNA (mRNA) alternative splicing of a large number of genes, including those involved in plant responses to light signaling. A comparative analysis of alternative splicing among single, double, and triple mutants showed that all three splicing factors coordinately regulate the alternative splicing of a subset of genes. Our study uncovered the function of a splicing factor that modulates light-regulated alternative splicing by interacting with photoactivated phyB and other splicing factors.
光信号被一组光感受器感知，对植物的生理、生长和发育有深远影响。红光/远红光吸收型光敏色素（phys）通过在多个水平上精细调节基因表达来调节这些方面。在这里，我们报告了一个 RNA 结合剪接因子 SWAP1（SWITCH1/SURP RNA-BINDING DOMAIN-CONTAINING PROTEIN1 的缩写）的鉴定和功能特征。功能丧失突变体对红光敏感，表现出与日照长度无关的早期开花表型。SWAP1 以光独立的方式与另外两个剪接因子（SFPS）和（RRC1）相互作用，并形成一个三元复合物。此外，SWAP1 与光激活的 phyB 物理相互作用，并与核 phyB 光体共定位。表型分析表明， 、 和 双突变体在红光下的下胚轴长度与各自的单突变体相似，表明它们在同一遗传途径中发挥作用。 双和 三突变体表现出多种表型，包括成虫期不育。深度 RNA 测序（RNA-seq）分析表明，SWAP1 调节大量基因的基因表达和前信使 RNA（mRNA）可变剪接，包括那些参与植物对光信号反应的基因。对单突变体、双突变体和三突变体的可变剪接进行比较分析表明，这三个剪接因子协同调节一组基因的可变剪接。我们的研究揭示了一个剪接因子的功能，该因子通过与光激活的 phyB 和其他剪接因子相互作用来调节光调控的可变剪接。
