bioRxiv Science⌕ Search

Biology subjects

DING, Y.

Publications and source records attributed to DING, Y..

8 recordsLinked to original sources

An ancient cis-element regulates translation of arginine decarboxylase to control downstream polyamine biosynthesis and stress responses

Polyamines (PAs) are ubiquitous metabolites that, despite their simple structure, profoundly influence plant growth, development, and stress adaptation. Their cellular levels are largely determined by arginine decarboxylase (ADC), a key rate-limiting enzyme in their biosynthesis. We previously identified a [~]50 bp GC-rich sequence in the 5' untranslated region (UTR) of plant ADC genes, termed the ADC-box, that is conserved across land plants. Transient reporter assays in tomato, in which ADC upstream regions were decoupled from their native coding sequences and fused to reporter genes, suggested that this element represses translation. However, its function in the native genomic context and its impact on PA homeostasis remain unclear. Here, we combined CRISPR-Cas9 genome editing, metabolite profiling, enzymatic assays, and RNA structure probing to define ADC-box function in tomato and in the seedless land plant Marchantia polymorpha, which retains a conserved [~]20 bp core region. Mutation of the M. polymorpha ADC-box increased ADC activity and altered PA levels, indicating that the ADC-box functions as a conserved translational repressor. In tomato, disruption of the ADC-boxes in SlADC1 and SlADC2 increased ADC activity, demonstrating that the ADC-box acts as a translational repressor in its native context. These ehects were most pronounced under cold stress, when ADC transcript levels increase, suggesting that the ADC-box buhers stress-induced translation. Metabolically, ADC-box disruption led to agmatine accumulation and alterations in upstream intermediates, while downstream PA pools remained largely unchanged. SHAPE analysis revealed that the tomato ADC-box folds into a three-stem RNA structure, with a central stem representing the major inhibitory module. ADC-box mutants displayed altered plant-microbe interactions, with enhanced resistance to Pseudomonas syringae and Tobacco rattle virus, but increased susceptibility to Ralstonia solanacearum and Tomato yellow leaf curl virus. Together, these findings establish the ADC-box as an evolutionarily conserved cis-regulatory element that stabilizes PA homeostasis and modulates plant-microbe interactions.

plant biology↗

RNA i-Motif Formation at Neutral pH

i-Motifs are non-canonical nucleic acid secondary structures formed in sequences rich in cytosine. Previous work has shown that DNA i-motifs may form at neutral pH and provided evidence to suggest they influence biological functions. RNA i-motifs are less stable than DNA i-motifs, so more questions surround the biological relevance of these structures in RNA. Using biophysical methods, we found that increasing cytosine tract lengths resulted in increased thermal stability but not pH stability. In ensemble solution experiments RNA i-motifs appear globally unfolded at neutral pH. However, single molecule experiments revealed that 1% of RNA i-motifs remain folded in solution. This has implications for the potential of formation of RNA i-motifs in cells.

biophysics↗

PlantRNA-FM: An Interpretable RNA Foundation Model for Exploration 1 Functional RNA Motifs in Plants

The complex language of plant RNA encodes a vast array of biological regulatory elements that orchestrate crucial aspects of plant growth, development, and adaptation to environmental stresses. Recent advancements in foundation models (FMs) have demonstrated their unprecedented potential to decipher complex language in biology. In this study, we introduced PlantRNA-FM, a novel high-performance and interpretable RNA FM specifically designed based on RNA features including both sequence and structure. PlantRNA-FM was pre-trained on an extensive dataset, integrating RNA sequences and RNA structure information from 1,124 distinct plant species. PlantRNA-FM exhibits superior performance in plant-specific downstream tasks, such as plant RNA annotation prediction and RNA translation efficiency (TE) prediction. Compared to the second-best FMs, PlantRNA-FM achieved an F1 score improvement of up to 52.45% in RNA genic region annotation prediction and up to 15.30% in translation efficiency prediction, respectively. Our PlantRNA-FM is empowered by our interpretable framework that facilitates the identification of biologically functional RNA sequence and structure motifs, including both RNA secondary and tertiary structure motifs across transcriptomes. Through experimental validations, we revealed novel translation-associated RNA motifs in plants. Our PlantRNA-FM also highlighted the importance of the position information of these functional RNA motifs in genic regions. Taken together, our PlantRNA-FM facilitates the exploration of functional RNA motifs across the complexity of transcriptomes, empowering plant scientists with novel capabilities for programming RNA codes in plants.

bioinformatics↗

Prediction of DNA i-Motifs Via Machine Learning

i-Motifs (iMs), are secondary structures formed in cytosine-rich DNA sequences and are involved in multiple functions in the genome. Although putative iM forming sequences are widely distributed in the human genome, the folding status and strength of putative iMs vary dramatically. Much previous research on iM has focused on assessing the iM folding properties using biophysical experiments. However, there are no dedicated computational tools for predicting the folding status and strength of iM structures. Here, we introduce a machine learning pipeline, iM-Seeker, to predict both folding status and structural stability of DNA iMs. The programme iM-Seeker incorporates a Balanced Random Forest classifier trained on genome-wide iMab antibody-based CUT&Tag sequencing data to predict the folding status and an Extreme Gradient Boosting regressor to estimate the folding strength according to both literature biophysical data and our in-house biophysical experiments. iM-Seeker predicts DNA iM folding status with a classification accuracy of 81% and estimates the folding strength with coefficient of determination (R2) of 0.642 on the test set. Model interpretation confirms that the nucleotide composition of the C-rich sequence significantly affects iM stability, with a positive correlation with sequences containing cytosine and thymine and a negative correlation with guanine and adenine. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/571121v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@11f4398org.highwire.dtl.DTLVardef@18eb7e9org.highwire.dtl.DTLVardef@cc49c6org.highwire.dtl.DTLVardef@1ff91a8_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioinformatics↗

RNA G-quadruplex structure contributes to cold adaptation in plants

Nucleotide composition is suggested to infer gene functionality and ecological adaptation of species to distinct environments. However, the underlying biological function of nucleotide composition dictating environmental adaptations is largely unknown. Here, we systematically analyzed the nucleotide compositions of transcriptomes across 1000 plants (1KP) and their corresponding habitats. Intriguingly, we found that plants growing in cold climates have guanine (G)-enriched transcriptomes, which are prone to forming RNA G-quadruplex structures. Both immunofluorescence detection and in vivo structure profiling revealed that RNA G-quadruplex formation in plants was globally enhanced in response to cold. Cold-responsive RNA G-quadruplexes strongly enhanced mRNA stability, rather than affecting translation. Disruption of individual RNA G-quadruplex promoted mRNA decay in the cold, leading to impaired plant cold response. Therefore, we propose that plants adopted RNA G-quadruplex structure as a molecular marker to facilitate their adaptation to the cold during evolution.

molecular biology↗

Multiscale 3D Genome Reorganization during Skeletal Muscle Stem Cell Lineage Progression and Muscle Aging

3D genome rewiring is known to influence spatiotemporal expression of lineage-specific genes and cell fate transition during stem cell differentiation and aging processes. Yet it is unknown how 3D architecture remodels and orchestrates transcriptional changes during skeletal muscle stem cell (also called satellite cell, SC) activation, proliferation and differentiation course. Here, using in situ Hi-C we comprehensively map the 3D genome topology reorganization at multiscale levels during mouse SC lineage progression and integrate with transcriptional and chromatin signatures to elucidate how 3D genome rewiring dictates gene expression program. Specifically, rewiring at compartment level is most pronounced when SC becomes activated. Striking loss in TAD border insulation and chromatin looping also occurs during early activation process. Meanwhile, TADs can also form TAD clusters and super-enhancer containing TAD clusters orchestrate stage-specific gene expression during SC early activation. Furthermore, we elucidate 3D chromatin regulation of key transcription factor, PAX7 and identify cis-regulatory elements that are crucial for local chromatin architecture and Pax7 expression. Lastly, 3D genome remodeling is profiled in SCs isolated from naturally aging mice, unveiling that geriatric SCs display a prominent gain in long-range contacts and loss of TAD border insulation. Genome compartmentalization and chromatin looping are evidently altered in aged SC while geriatric SC display a more prominent loss in strength of TAD borders. Together, our results implicate 3D chromatin extensively reorganizes at multiple architectural levels and underpin the transcriptome remodeling during SC lineage development and SC aging.

cell biology↗

In vivo nuclear RNA structurome reveals RNA-structure regulation of mRNA processing in plants

mRNA processing is critical for gene expression. A challenge in regulating mRNA processing is how to recognize the actual mRNA processing sites, such as splice and polyadenylation sites, when the sequence content is insufficient for this purpose. Previous studies suggested that RNA structure affects mRNA processing. However, the regulatory role of RNA structure in mRNA processing remains unclear. Here, we performed in vivo selective 2-hydroxyl acylation analysed by primer extension (SHAPE) chemical profiling on Arabidopsis nuclear RNAs and generated the in vivo nuclear RNA structure landscape. We found that nuclear mRNAs fold differently from cytosolic mRNAs. Notably, we discovered a two-nucleotide single-stranded RNA structure feature upstream of 5 splice sites that is strongly associated with splicing and the selection of alternative 5 splice sites. Moreover, we found the single-strandedness of branch point is also associated with 3 splice site recognition. We also identified an RNA structure feature comprising two close-by single-stranded regions that is specifically associated with both polyadenylation and alternative polyadenylation events. Our work demonstrates an RNA structure regulatory mechanism for mRNA processing.

plant biology↗

RNA G-quadruplex structures exist and function in vivo

Guanine-rich sequences are able to form complex RNA structures termed RNA G-quadruplexes in vitro. Because of their high stability, RNA G-quadruplexes are proposed to exist in vivo and are suggested to be associated with important biological relevance. However, there is a lack of direct evidence for RNA G-quadruplex formation in living cells. Therefore, it is unclear whether any purported functions are associated with the specific sequence content or the formation of an RNA G-quadruplex structure. Here, we profiled the landscape of those guanine-rich regions with the in vitro folding potential in the Arabidopsis transcriptome. We found a global enrichment of RNA G-quadruplexes with two G-quartets whereby the folding potential is strongly influenced by RNA secondary structures. Using in vitro and in vivo RNA chemical structure profiling, we determined that hundreds of RNA G-quadruplex structures are strongly folded in both Arabidopsis and rice, providing direct evidence of RNA G-quadruplex formation in living eukaryotic cells. Subsequent genetic and biochemical analysis showed that RNA G-quadruplex folding was sufficient to regulate translation and modulate plant growth. Our study reveals the existence of RNA G-quadruplex in vivo, and indicates that RNA G-quadruplex structures act as important regulators of plant development and growth.

plant biology↗