Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Shijiazhuang 050022, China.
The College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China.
Int J Mol Sci. 2021 Oct 28;22(21):11692. doi: 10.3390/ijms222111692.
The heterotrimeric G-protein mediates growth and development by perceiving and transmitting signals in multiple organisms. Alternative splicing (AS), a vital process for regulating gene expression at the post-transcriptional level, plays a significant role in plant adaptation and evolution. Here, we identified five splicing variants of G subunit gene ( to ), which showed expression divergence during wheat polyploidization, and differential function in grain weight and size determination. overexpression significantly reduced grain weight by 5.89% and grain length by 5.04%, while - overexpression did not significantly alter grain size compared to wild type. Overexpressing significantly increased the grain weight by 5.70% and grain length by 4.30%. Biochemical assays revealed that isoforms (TaGS3.1-3.4) with an intact OSR domain interact with WGB1 to form active G heterodimers that further interact with WGA1 to form inactive G heterotrimers. Truncated isoforms , which lack the C-terminal Cys-rich region but have enhanced binding affinity to WGB1, antagonistically compete with to bind WGB1, while with an incomplete OSR domain does not interact with WGB1. Taking these observations together, we proposed that differentially regulates grain size via AS, providing a strategy by which the grain size is fine-tuned and regulated at the post-transcriptional level.
三聚体 G 蛋白通过感知和传递多种生物中的信号来介导生长和发育。可变剪接（AS）是在转录后水平上调节基因表达的重要过程，在植物的适应和进化中发挥着重要作用。在这里，我们鉴定了五个 G 亚基基因（）的剪接变体，它们在小麦多倍化过程中表现出表达差异，并在籽粒重量和大小决定方面具有不同的功能。过表达显著降低了 5.89%的籽粒重量和 5.04%的籽粒长度，而-过表达与野生型相比，对籽粒大小没有显著影响。过表达显著增加了 5.70%的籽粒重量和 4.30%的籽粒长度。生化分析表明，具有完整 OSR 结构域的 TaGS3.1-3.4 同工型与 WGB1 相互作用形成有活性的 G 异源二聚体，该异源二聚体进一步与 WGA1 相互作用形成无活性的 G 三聚体。缺失 C 端富含半胱氨酸区域但与 WGB1 结合亲和力增强的截短同工型与 竞争性结合 WGB1，而缺失 OSR 结构域的 则不与 WGB1 相互作用。综上所述，我们提出通过 AS 差异调节籽粒大小，为在转录后水平上精细调控和调节籽粒大小提供了一种策略。
