The Role of Pumilio RNA Binding Protein in Plants

From genes to traits: Trends in RNA-binding proteins and their role in plant trait development: A review

RNA-binding proteins (RBPs) are essential for cellular functions by attaching to RNAs, creating dynamic ribonucleoprotein complexes (RNPs) essential for managing RNA throughout its life cycle. These proteins are critical to all post-transcriptional processes, impacting vital cellular functions during development and adaptation to environmental changes. Notably, in plants, RBPs are critical for adjusting to inconsistent environmental conditions, with recent studies revealing that plants possess, more prominent, and both novel and conserved RBP families compared to other eukaryotes. This comprehensive review delves into the varied RBPs covering their structural attributes, domain base function, and their interactions with RNA in metabolism, spotlighting their role in regulating post-transcription and splicing and their reaction to internal and external stimuli. It highlights the complex regulatory roles of RBPs, focusing on plant trait regulation and the unique functions they facilitate, establishing a foundation for appreciating RBPs' significance in plant growth and environmental response strategies.

Proxiome assembly of the plant nuclear pore reveals an essential hub for gene expression regulation

The nuclear pore complex (NPC) is vital for nucleocytoplasmic communication. Recent evidence emphasizes its extensive association with proteins of diverse functions, suggesting roles beyond cargo transport. Yet, our understanding of NPC's composition and functionality at this extended level remains limited. Here, through proximity-labelling proteomics, we uncover both local and global NPC-associated proteome in Arabidopsis, comprising over 500 unique proteins, predominantly associated with NPC's peripheral extension structures. Compositional analysis of these proteins revealed that the NPC concentrates chromatin remodellers, transcriptional regulators and mRNA processing machineries in the nucleoplasmic region while recruiting translation regulatory machinery on the cytoplasmic side, achieving a remarkable orchestration of the genetic information flow by coupling RNA transcription, maturation, transport and translation regulation. Further biochemical and structural modelling analyses reveal that extensive interactions with nucleoporins, along with phase separation mediated by substantial intrinsically disordered proteins, may drive the formation of the unexpectedly large nuclear pore proteome assembly.

Comprehensive Identification of the Pum Gene Family and Its Involvement in Kernel Development in Maize

The Pumilio (Pum) RNA-binding protein family regulates post-transcription and plays crucial roles in stress response and growth. However, little is known about Pum in plants. In this study, a total of 19 ZmPum genes were identified and classified into two groups in maize. Although each ZmPum contains the conserved Pum domain, the ZmPum members show diversity in the gene and protein architectures, physicochemical properties, chromosomal location, collinearity, cis-elements, and expression patterns. The typical ZmPum proteins have eight α-helices repeats, except for ZmPum2, 3, 5, 7, and 14, which have fewer α-helices. Moreover, we examined the expression profiles of ZmPum genes and found their involvement in kernel development. Except for ZmPum2, ZmPum genes are expressed in maize embryos, endosperms, or whole seeds. Notably, ZmPum4, 7, and 13 exhibited dramatically high expression levels during seed development. The study not only contributes valuable information for further validating the functions of ZmPum genes but also provides insights for improvement and enhancing maize yield.

Dosage sensitivity to Pumilio1 variants in the mouse brain reflects distinct molecular mechanisms

Different mutations in the RNA-binding protein Pumilio1 (PUM1) cause divergent phenotypes whose severity tracks with dosage: a mutation that reduces PUM1 levels by 25% causes late-onset ataxia, whereas haploinsufficiency causes developmental delay and seizures. Yet PUM1 targets are derepressed to equal degrees in both cases, and the more severe mutation does not hinder PUM1's RNA-binding ability. We therefore considered the possibility that the severe mutation might disrupt PUM1 interactions, and identified PUM1 interactors in the murine brain. We find that mild PUM1 loss derepresses PUM1-specific targets, but the severe mutation disrupts interactions with several RNA-binding proteins and the regulation of their targets. In patient-derived cell lines, restoring PUM1 levels restores these interactors and their targets to normal levels. Our results demonstrate that dosage sensitivity does not always signify a linear relationship with protein abundance but can involve distinct mechanisms. We propose that to understand the functions of RNA-binding proteins in a physiological context will require studying their interactions as well as their targets.

RNA-binding proteins and their role in translational regulation in plants

Translation is a fundamental process for life that needs to be finely adapted to the energetical, developmental and environmental conditions; however, the molecular mechanisms behind such adaptation are not yet fully understood. By directly recognizing and binding to cis-elements present in their target mRNAs, RBPs govern all post-transcriptional regulatory processes. They orchestrate the balance between mRNA stability, storage, decay, and translation of their client mRNAs, playing a crucial role in the modulation of gene expression. In the last years exciting discoveries have been made regarding the roles of RBPs in fine-tuning translation. In this review, we focus on how these RBPs recognize their targets and modulate their translation, highlighting the complex and diverse molecular mechanisms implicated. Since the repertoire of RBPs keeps growing, future research promises to uncover new fascinating means of translational modulation, and thus, of gene expression.