Regulation of ribosomal protein genes: An ordered anarchy

Piezoelectric nanofilms fabricated by coaxial electrospun polycaprolactone/Barium titanate promote Achilles tendon regeneration by reducing IL-17A/NF-κB-mediated inflammation

Tendon injuries are often exacerbated by persistent inflammation, which hampers tissue regeneration. In this study, we developed a noninvasive, wirelessly controlled, and self-powered piezoelectric nanofilm fabricated by coaxial electrospinning of polycaprolactone (PCL) and tetragonal barium titanate nanoparticles (BTO), and investigated its roles in modulating inflammation and repairing Achilles tendon defects as well as the mechanism in a rat model. In vitro study and in vivo study upon subcutaneous implantation showed that the piezoelectric PCL/BTO nanofilms could inhibit M1 macrophage polarization and reduce the secretion of inflammatory factors. Moreover, when bridging an Achilles tendon defect, the nanofilms could promote tenogenic gene expression including collagen deposition, and collagen remodeling, facilitate functional tendon recovery and significantly reduce tissue inflammation by suppressing M1 macrophage polarization and promoting M2 polarization. Moreover, the piezoelectric stimulation could also enhance tendon regeneration by inhibiting angiogenesis, reducing lipid deposition, and decreasing ectopic ossification. Mechanistically, the piezoelectric nanofilms reduced tissue inflammation mainly via inhibiting the nuclear factor (NF)-κB signaling pathway that is mediated by interleukin (IL)-17A secreted from CD3+ T cells, and thus to reduce proinflammatory factors, such as IL-1β and IL-6, inducible nitric oxide synthase, monocyte chemoattractant protein-1, and tumor necrosis factor-α. These findings indicate the potential of piezoelectric stimulation in immunomodulation, and in promoting tendon regeneration via IL-17A/NF-κB-mediated pathway.

Sex-biased zinc responses modulate ribosomal protein expression, protein synthesis and social defects in Cttnbp2 mutant mice

Autism spectrum disorders (ASD) are neurodevelopmental conditions influenced by genetic mutations, dietary factors, and sex-specific mechanisms, yet the interplay of these factors remains elusive. Here, we investigate the sex-biased responses of mutant mice carrying an ASD-associated mutation in Cttnbp2 to dietary zinc supplementation using behavioral assays, proteomic and bioinformatic analyses, and puromycin pulse labeling to assess protein synthesis. Our results demonstrate that zinc supplementation enhances ribosomal protein expression and protein synthesis and increases the density and size of dendritic spines in male Cttnbp2 mutant mice, alleviating male-biased social deficits. Analyses of neuronal cultures further revealed that neurons, not astrocytes, respond to zinc to enhance protein synthesis. In contrast, female Cttnbp2 mutants exhibit resilience to differential zinc intake, even under zinc deprivation. Elevated mTOR phosphorylation and increased protein levels of translational initiation factors in female brains may provide a protective mechanism, reducing their sensitivity to zinc deficiency. Cttnbp2 mutations heighten male vulnerability to zinc deprivation, impairing social behaviors. These findings highlight zinc-regulated ribosomal protein expression and protein synthesis as critical mediators of sex-specific ASD phenotypes, offering new insights into dietary interventions.

Beyond the ORF: Paralog-specific regulation of RPS7/eS7 mRNAs via 3'-UTRs and promoter sequences

In a classical view, each paralogous ribosomal protein (RP) is equally synthesized and integrated into the ribosome. Therefore, RP-paralog mRNAs are generally believed to be similarly regulated on their transcription and/or stability. In this paper, we report that two Rps7p/eS7 paralogs of Saccharomyces cerevisiae are differently regulated; deletion of RPS7A upregulates RPS7B paralogous mRNA expression but not vice versa. Their 3'-UTR sequences critically regulated the stabilities of both RPS7A and RPS7B mRNAs. Alterations in these sequences led to a diminished expression of RPS7A and RPS7B mRNAs in a transcript-dependent manner, suggesting that RPS7-paralog mRNAs have different properties for their expression and/or stability. The C-terminal tagging of the ORF and mutation analyses in the 3'-UTR indicate that both RPS7-paralog mRNAs critically rely on their 3'-UTRs for mRNA expressions and/or stabilities. We also found that activities of both RPS7A and RPS7B promoters are regulated by abundance of Rps7Ap and that Fhl1p, a key transcriptional regulator of RP genes, is essential for transcription of RPS7B but not RPS7A while simultaneous deletion of a consensus sequence for Fhl1p in the RPS7A promoter region and the FHL1 gene completely abolishes the promoter activity. These results indicate that yeast has a distinct buffering system for Rps7p production between the two RPS7-paralogs, which is sensitive to variation on their 3'-UTRs and is partially mediated in a transcription-dependent manner.

Structures of aberrant spliceosome intermediates on their way to disassembly

Intron removal during pre-mRNA splicing is of extraordinary complexity and its disruption causes a vast number of genetic diseases in humans. While key steps of the canonical spliceosome cycle have been revealed by combined structure-function analyses, structural information on an aberrant spliceosome committed to premature disassembly is not available. Here, we report two cryo-electron microscopy structures of post-Bact spliceosome intermediates from Schizosaccharomyces pombe primed for disassembly. We identify the DEAH-box helicase-G-patch protein pair (Gih35-Gpl1, homologous to human DHX35-GPATCH1) and show how it maintains catalytic dormancy. In both structures, Gpl1 recognizes a remodeled active site introduced by an overstabilization of the U5 loop I interaction with the 5' exon leading to a single-nucleotide insertion at the 5' splice site. Remodeling is communicated to the spliceosome surface and the Ntr1 complex that mediates disassembly is recruited. Our data pave the way for a targeted analysis of splicing quality control.

Proteomics-based characterization of ribosome heterogeneity in adult mouse organs

The translation process, leading to protein synthesis from mRNA, has been long thought to be invariable in all cellular organisms. Increasing evidence shows that it is finely regulated by variable features of the translation machinery. Notably, ribosomes, the functional units of protein synthesis, are suggested to display variations in their composition, depending on the developmental stage, cell type or physio-pathological context, thus hinting a new level of actionable regulation of gene expression. Yet, a comprehensive map of the heterogeneity of ribosome composition in ribosomal proteins (RPs) in different organs and tissues is not available. In this work, we explored tissue-specific ribosome heterogeneity using mass spectrometry-based quantitative proteomic characterization of ribosomal fractions purified from 14 adult mouse organs and tissues. We performed crossed clustering and statistical analyses of RP composition to highlight stable, variable and tissue-specific RPs across organs and tissues. Focusing on specific RPs, we validated their varying abundances using a targeted proteomic approach and western blot analyses, providing further insights into the tissue-specific ribosome RP signature. Finally, we investigated the origin of RP variations in ribosome fraction of the different tissues, by comparing RP relative amounts in our ribosomal proteomic dataset with their corresponding transcript abundances in three independent transcriptomic datasets. Interestingly, we found that, in some tissues, the RP abundance in purified ribosomes does not always correlate with the corresponding RP transcript level, arguing for a translational regulation of RP expression, and/or a regulated incorporation of RPs into ribosomes. Altogether, our data support the notion of a tissue-specific RP signature of ribosomes, which opens avenues to study how specific ribosomal composition provides an additional level of regulation to control gene expression in different tissues and organs.

How the concentric organization of the nucleolus and chromatin ensures accuracy of ribosome biogenesis and drives transport

The biogenetic transport of ribosomal subunit precursors must be conducted with precision to ensure production of functional ribosomes. With a focus on ribosome biogenesis in higher eukaryotic cells, we here discuss the following: (1) the concentric organization of the phases/subcompartments of the nucleus-including chromatin, (2) why the nucleolus reorganizes when ribosomal RNA synthesis is inhibited, and (3) the mechanism responsible for vectorial transport of particulate subunit intermediates between subcompartments. We call attention to evidence that (1) nucleolar proteins can access the entire volume of the nucleus, (2) that the packaging of rDNA is a key determinant of topology, (3) the constancy of contacts between subcompartments, and the likely importance of a Brownian ratchet for imparting both directionality and quality control upon transport. Transport appears to depend on "self-immersion," whereby the surfaces of particulate intermediates successively interact with components of the surrounding milieux, each of which may be thought of as a distinct solvent. The result is a vectorial and ordered process.

Drosophila architectural proteins M1BP and Opbp cooperatively form the active promoter of a ribosomal protein gene

BACKGROUND

In Drosophila, architectural proteins are frequently found in promoters, including those of genes with extremely high expression levels, such as ribosomal protein genes (RPGs). The involvement of several of these proteins in gene regulation in Drosophila has been shown, but the exact mechanisms of their possible cooperative action have not been fully elucidated.

RESULTS

In this study we dissected the contribution of the architectural proteins Opbp and M1BP, which are co-localized at several RPG promoters near the transcription start site, to promoter functioning. We found that Opbp has two domains that directly interact with CP190, Putzig (Pzg), and Chromator (Chro) proteins, the cofactors which are required for the activation of housekeeping (hk) gene promoters. These domains have redundant functions in vivo and can tether the cofactors forming open chromatin regions when are artificially recruited to the "closed" chromatin. Additionally, we observed interactions between M1BP and the same cofactors. In the transgene assay, the transcription driven by the 192-bp part of Rpl27A RPG promoter is fully dependent on the presence of at least one Opbp or M1BP binding site and it is sufficient for the very high activity of this promoter integrated into the hk gene cluster and moderate expression outside the cluster, while presence of both sites even more facilitates transcription.

CONCLUSIONS

This study demonstrates that different architectural proteins can work independently and in cooperation and fulfill partially redundant functions in the activation of RPG promoters.

Artificial intelligence-assisted RNA-binding protein signature for prognostic stratification and therapeutic guidance in breast cancer

Background

Breast cancer is the most common malignancy in women globally, with significant heterogeneity affecting prognosis and treatment. RNA-binding proteins play vital roles in tumor progression, yet their prognostic potential remains unclear. This study introduces an Artificial Intelligence-Assisted RBP Signature (AIRS) model to improve prognostic accuracy and guide personalized treatment.

Methods

Data from 14 BC cohorts (9,000+ patients) were analyzed using 108 machine learning model combinations. The AIRS model, built on three key RBP genes (PGK1, MPHOSPH10, MAP2K6), stratified patients into high- and low-risk groups. Genomic alterations, single-cell transcriptomics, tumor microenvironment characteristics, and drug sensitivity were assessed to uncover AIRS-associated mechanisms.

Results

The AIRS model demonstrated superior prognostic performance, surpassing 106 established signatures. High AIRS scores correlated with elevated tumor mutational burden, specific copy number alterations, and an immune-suppressive TME. Single-cell analysis revealed functional heterogeneity in epithelial cells, linking high AIRS scores to pathways like transcription factor binding. Regulatory network analysis identified key transcription factors such as MYC. Low AIRS scores predicted better responses to immune checkpoint inhibitors, while drug sensitivity analysis highlighted panobinostat and paclitaxel as potential therapies for high-risk patients.

Conclusions

The AIRS model offers a robust tool for BC prognosis and treatment stratification, integrating genomic, transcriptomic, and single-cell data. It provides actionable insights for personalized therapy, paving the way for improved clinical outcomes. Future studies should validate findings across diverse populations and expand functional analyses.

Novel Artificial 5'UTR Increase Modified mRNA Translation When Injected into Mouse Heart

Background/Objectives: Modified messenger RNA (modRNA) is a promising gene delivery method used to upregulate genes in cardiac tissue, with applications in both clinical and preclinical settings to prevent cardiac remodeling after ischemic injury. The 5' untranslated region (5'UTR) plays a crucial role in regulating the translation efficiency of mRNA into functional proteins. Due to the high production cost and short half-life of modRNA, it is essential to identify novel 5'UTR designs that enhance modRNA translation in the heart. Methods: Here, we present an artificial 5'UTR, termed "Top Heart 5'UTR", designed based on ribonucleotide frequency analyses of 1000 genes highly expressed in the heart. This novel artificial 5'UTR contains a unique 20-nucleotide sequence, consisting of 11 previously uncharacterized nucleotides (CCCCCGCCCCC) and 9 well-described nucleotides from the Kozak sequence upstream of the start codon (ATG). Results: This design significantly improves modRNA translation efficiency in cardiomyocytes (CMs) and heart cells both in vitro and in vivo. Specifically, the Top Heart 5'UTR increases translation efficiency by approximately 30-60% in both mouse and human CMs compared to a standard 5'UTR control. Moreover, the artificial 5'UTR induces a 2-2.5 times higher translation of modRNA in the mouse heart 24 and 48 h post-delivery. Conclusions: Our findings may contribute to the development of a superior modRNA platform for use in preclinical and clinical studies, potentially allowing reduced dosages or increased gene expression at the same dosage level. This approach can be extended to identify optimized 5'UTRs for various cell types or organs, including applications in cancer therapies.

Developmental deletion of amyloid precursor protein precludes transcriptional and proteomic responses to brain injury

INTRODUCTION

Amyloid precursor protein (APP) undergoes striking changes following traumatic brain injury (TBI). Considering its role in the control of gene expression, we investigated whether APP regulates transcription and translation following TBI.

METHODS

We assessed brain morphology (n = 4-9 mice/group), transcriptome (n = 3 mice/group), proteome (n = 3 mice/group), and behavior (n = 17-27 mice/group) of wild-type (WT) and APP knock-out (KO) mice either untreated or 10-weeks following TBI.

RESULTS

After TBI, WT mice displayed transcriptional programs consistent with late stages of brain repair, hub genes were predicted to impact translation and brain proteome showed subtle changes. APP KO mice largely replicated this transcriptional repertoire, but showed no transcriptional nor translational response to TBI.

DISCUSSION

The similarities between WT mice following TBI and APP KO mice suggest that developmental APP deficiency induces a condition reminiscent of late stages of brain repair, hampering the control of gene expression in response to injury.

HIGHLIGHTS

10-weeks after TBI, brains exhibit transcriptional profiles consistent with late stage of brain repair. Developmental APP deficiency maintains brains perpetually in an immature state akin to late stages of brain repair. APP responds to TBI by changes in gene expression at a transcriptional and translational level. APP deficiency precludes molecular brain changes in response to TBI.

Decoding Plant Ribosomal Proteins: Multitasking Players in Cellular Games

Ribosomal proteins (RPs) were traditionally considered as ribosome building blocks, serving exclusively in ribosome assembly. However, contemporary research highlights their involvement in additional translational roles, as well as diverse non-ribosomal activities. The functional diversity of RPs is further enriched by the presence of 2-7 paralogs per RP family in plants, suggesting that these proteins may perform distinct, specialized functions. The spatiotemporal expression of RP paralogs allows for the assembly of unique ribosomes (ribosome heterogeneity), enabling the selective translation of specific mRNAs, and producing specialized proteins essential for plant functioning. Additionally, RPs that operate independently of ribosomes as free molecules may regulate a wide range of physiological processes. RPs involved in protein biosynthesis within the cytosol, mitochondria, or plastids are encoded by distinct genes, which account for their functional specialization. Notably, RPs associated with plastid or mitochondrial ribosomes, beyond their canonical roles in these organelles, also contribute to overall plant development and functionality, akin to their cytosolic counterparts. This review explores the roles of RPs in different cellular compartments, the presumed molecular mechanisms underlying their functions, and the involvement of other molecular factors that cooperate with RPs in these processes. In addition to the new RP nomenclature introduced in 2022/2023, the old names are also applied.

Implication of ribosomal protein in abiotic and biotic stress

MAIN CONCLUSION

This review article explores the intricate role, and regulation of ribosomal protein in response to stress, particularly emphasizing their pivotal role to ameliorate abiotic and biotic stress conditions in crop plants. Plants must coordinate ribosomes production to balance cellular protein synthesis in response to environmental variations and pathogens invasion. Over the past decade, research has revealed ribosome subgroups respond to adverse conditions, suggesting that this tight coordination may be grounded in the induction of ribosome variants resulting in differential translation outcomes. Furthermore, an increasing snumber of studies on plant ribosomes have made it possible to explore the stress-regulated expression pattern of ribosomal protein large subunit (RPL) and ribosomal protein small subunit (RPS) genes. In this perspective, we reviewed the literature linking ribosome heterogeneity to plants' abiotic and biotic stress responses to offer an overview on the expression and biological function of ribosomal components including specialized translation of individual transcripts and its implications for the regulation and expression of important gene regulatory networks, along with phenotypic analysis in ribosomal gene mutations in physiologic and pathologic processes. We also highlight recent advances in understanding the molecular mechanisms behind the transcriptional regulation of ribosomal genes linked to stress events. This review may serve as the foundation of novel strategies to customize cultivars tolerant to challenging environments without the yield penalty.

Built differently or defective: can RNA exosomopathies cause ribosome heterogeneity?

The RNA exosome is an essential, evolutionarily conserved ribonuclease required for processing and degradation of key cellular RNAs. The complex maintains RNA homeostasis within every cell by ensuring the proper maturation, quality control and turnover of various RNA species including rRNAs. A growing list of diseases, collectively termed RNA exosomopathies, are caused by mutations in genes encoding structural subunits of the RNA exosome complex. RNA exosomopathies often result in tissue-specific defects, particularly manifesting as neurological disorders, which is intriguing given the ubiquitous functions and expression of the RNA exosome. One such ubiquitous, essential function of the RNA exosome is its involvement in ribosome biogenesis. In this review, we discuss the established connections between the RNA exosome and ribosome biogenesis, exploring the potential mechanisms through which RNA exosomopathies could influence ribosome heterogeneity, leading to aberrant translation and pathogenesis. We highlight the critical need for research in this area that can aid in understanding the complex aetiology of RNA exosomopathies and the future development of therapeutic strategies to mitigate pathology.This article is part of the discussion meeting issue 'Ribosome diversity and its impact on protein synthesis, development and disease'.

Small nucleolar RNAs: the hidden precursors of cancer ribosomes

Ribosomes are heterogeneous in terms of their constituent proteins, structural RNAs and ribosomal RNA (rRNA) modifications, resulting in diverse potential translatomes. rRNA modifications, guided by small nucleolar RNAs (snoRNAs), enable fine-tuning of ribosome function and translation profiles. Recent studies have begun linking dysregulation of snoRNAs, via rRNA modifications, to tumourigenesis. Deciphering the specific contributions of individual rRNA modifications to cancer hallmarks and identifying snoRNAs with oncogenic potential could lead to novel therapeutic strategies. These strategies might target snoRNAs or exploit the dependence of cancer cells on specific rRNA modification sites, potentially disrupting aberrant ribosomal translation programs and hindering tumour growth. This review discusses current evidence and challenges in linking changes in snoRNA expression to rRNA modification and cancer biology.This article is part of the discussion meeting issue 'Ribosome diversity and its impact on protein synthesis, development and disease'.

HTSinfer: inferring metadata from bulk Illumina RNA-Seq libraries

SUMMARY

The Sequencing Read Archive is one of the largest and fastest-growing repositories of sequencing data, containing tens of petabytes of sequenced reads. Its data is used by a wide scientific community, often beyond the primary study that generated them. Such analyses rely on accurate metadata concerning the type of experiment and library, as well as the organism from which the sequenced reads were derived. These metadata are typically entered manually by contributors in an error-prone process, and are frequently incomplete. In addition, easy-to-use computational tools that verify the consistency and completeness of metadata describing the libraries to facilitate data reuse, are largely unavailable. Here, we introduce HTSinfer, a Python-based tool to infer metadata directly and solely from bulk RNA-sequencing data generated on Illumina platforms. HTSinfer leverages genome sequence information and diagnostic genes to rapidly and accurately infer the library source and library type, as well as the relative read orientation, 3' adapter sequence and read length statistics. HTSinfer is written in a modular manner, published under a permissible free and open-source license and encourages contributions by the community, enabling easy addition of new functionalities, e.g. for the inference of additional metrics, or the support of different experiment types or sequencing platforms.

AVAILABILITY AND IMPLEMENTATION

HTSinfer is released under the Apache License 2.0. Latest code is available via GitHub at https://github.com/zavolanlab/htsinfer, while releases are published on Bioconda. A snapshot of the HTSinfer version described in this article was deposited at Zenodo at 10.5281/zenodo.13985958.

Gene Set Enrichment Analysis in Zebrafish Embryos Is Susceptible to False-Positive Results in the Absence of Differentially Expressed Genes

High-throughput gene expression studies commonly employ pathway analyses to infer biological meaning from lists of differentially expressed genes (DEGs). In toxicology and pharmacology studies, treatment groups are analysed against vehicle controls to identify DEGs and altered pathways. Previously, we empirically quantified false-positive rates of DEGs in gene expression data from pools of vehicle-treated zebrafish embryos to determine appropriate study designs (sample and pool size). Here, the same data were subject to Over-Representation Analysis (ORA) and Gene Set Enrichment Analysis (GSEA) to identify false-positive enriched pathways. As expected, the number of false-positive ORA results was lowest where pool and sample sizes were largest (conditions which also generated the fewest significant DEGs). In contrast, the frequency of GSEA false-positives generated through the fast GSEA (fgsea) algorithm increased with pool and sample size and was highest for simulations that generated 0 DEGs, with ribosomal gene sets significantly enriched with the highest frequency. We describe 2 distinct mechanisms by which GSEA generated these false-positive results, both of which are most likely to generate significant gene sets under conditions where expression differences are particularly low. Finally, GSEA analyses were repeated using 1 alternative GSEA algorithm (CERNO) and 11 different ranking statistics. In almost every analysis, the number of significant results was highest where pool size was highest, with ribosome as the more frequently enriched gene set, suggesting our observations to be generalizable to different implementations of GSEA. These results from zebrafish embryos suggest caution in interpreting any GSEA results in contrasts where there are no DEGs.

Filamin A suppresses the expression of ribosomal protein genes by controlling the activity of an EGR1-Sp1-GCN5/PCAF pathway in human cells

Human ribosome biogenesis requires four types of rRNA molecules and almost eighty cytoplasmic ribosomal proteins (CRPs) to be assembled together. . In the previous work, we showed that cytoskeletal filamin A (FLNA) can suppress rRNA expression in human cells. Thus, we hypothesized that FLNA can modulate the expression of CRPs because human cells have to coordinate cellular ribosome biogenesis. Here, we show that the absence of FLNA enhances the expression of most CRP genes assayed in the work, whereas the presence of FLNA dampens the expression of these CRP genes in several transformed cell types. The analysis of RNA-seq data revealed that FLNA silencing activated the expression of almost all CRPs and many mitochondrial RP genes in SaOS2 cells. These results indicate that FLNA acts as a negative regulator in CRP expression in human cells. Mechanistically, FLNA inhibits the expression of GCN5 and PCAF, which consequently impedes the occupancies of GCN5, PCAF, andH3K9ac at CRP gene loci. Both GCN5 and PCAF participates in the regulation of CRP expression either mediated by FLNA or independently. We show that FLNA silencing activates Sp1 expression and the activation of Sp1 stimulates the expression of Gcn5 and Pcaf genes. Further analysis revealed that EGR1 can bind the Sp1 gene promoter and activate Sp1 transcription. Collectively, this study revealed an EGR1-Sp1-GCN5/PCAF pathway by which FLNA modulates the expression of CRP genes. These findings shed light on how human cells coordinate the expression of CRP genes during ribosomal biogenesis.

DPANN symbiont of Haloferax volcanii accelerates xylan degradation by the non-host haloarchaeon Halorhabdus sp

This study examines a natural consortium of halophilic archaea, comprising xylan-degrading Halorhabdus sp. SVX81, consortium cohabitant Haloferax volcanii SVX82 (formerly H. lucentense SVX82), and its DPANN ectosymbiont Ca. Nanohalococcus occultus SVXNc. Transcriptomics and targeted metabolomics demonstrated that the tripartite consortium outperformed individual and the Halorhabdus sp. SVX81 with H. volcanii SVX82 bipartite cultures in xylan degradation, exhibiting a division of labor: the DPANN symbiont processed glycolysis products, while other members performed xylan depolymerization and biosynthesis of essential compounds. Electron microscopy and cryo-electron tomography revealed the formation of heterocellular biofilms interlinked by DPANN cells. The findings demonstrated that DPANN symbionts can interact directly with other members of microbial communities, which are not their primary hosts, influencing their gene expression. However, DPANN proliferation requires their primary host presence. The study highlights the collective contribution of consortium members to xylan degradation and their potential for biotechnological applications in the management of hypersaline environments.

The Unveiled Novel regulator of Adeno-associated virus production in HEK293 cells

The field of gene therapy using Adeno-associated viral (AAV) vector delivery is rapidly advancing in the biotherapeutics industry. Despite its successes, AAV manufacturing remains a challenge due to limited production yields. The triple plasmid transfection of HEK293 cells represents the most extensively utilized system for AAV production. The regulatory factors and mechanisms underlying viral production in HEK293 cells are largely unknown. In this study, we isolated high-titer AAV production clones from a parental HEK293 population using a single limiting dilution step, and subsequently elucidating their underlying molecular mechanisms through whole transcriptome analysis. LncRNA TCONS_00160397 was upregulated in clones and shown to promoted HEK293 cells proliferation and improved the titer of AAV production. Mechanistically, results from proteomics and metabolomics indicated that TCONS_00160397 regulated the ABC transporters pathway. These findings furnish a rich repository of knowledge and actionable targets for the rational optimization of HEK293-based producer lines, thereby paving the way for tangible improvements in AAV vector output and expediting the broad implementation of gene therapies.

Promoted read-through and mutation against pseudouridine-CMC by an evolved reverse transcriptase

Pseudouridine (Ψ) is an abundant RNA chemical modification that plays critical biological functions. Current Ψ detection methods are limited in identifying Ψs at base-resolution in U-rich sequence contexts, where Ψ occurs frequently. Here we report "Mut-Ψ-seq" that utilizes the classic N-cyclohexyl N'-(2-morpholinoethyl)carbodiimide (CMC) agent and an evolved reverse transcriptase ("RT-1306") for Ψ mapping at base-resolution. CMC selectively labels Ψs in RNA forming the CMC-Ψ adduct and we show that RT-1306 presents promoted read-through and mutation against the CMC-Ψ. We report a high-confidence list of Ψ sites in polyA-enriched RNAs from HEK-293T cells identified by orthogonal chemical treatments (CMC and bisulfite). The mutation signatures resolve the position of Ψ in UU-containing sequences, revealing diverse occurrence of Ψs in such sequences. This work provides methods and datasets for biological research of Ψ, and expands the toolkit for epitranscriptomic studies by combining the reverse transcriptase engineering and selective chemical labeling strategies.

Transcription factors induce differential splicing of duplicated ribosomal protein genes during meiosis

In baker's yeast, genes encoding ribosomal proteins often exist as duplicate pairs, typically with one 'major' paralog highly expressed and a 'minor' less expressed paralog that undergoes controlled expression through reduced splicing efficiency. In this study, we investigate the regulatory mechanisms controlling splicing of the minor paralog of the uS4 protein gene (RPS9A), demonstrating that its splicing is repressed during vegetative growth but upregulated during meiosis. This differential splicing of RPS9A is mediated by two transcription factors, Rim101 and Taf14. Deletion of either RIM101 or TAF14 not only induces the splicing and expression of RPS9A with little effect on the major paralog RPS9B, but also differentially alters the splicing of reporter constructs containing only the RPS9 introns. Both Rim101 and Taf14 co-immunoprecipitate with the chromatin and RNA of the RPS9 genes, indicating that these transcription factors may affect splicing co-transcriptionally. Deletion of the RPS9A intron, RIM101 or TAF14 dysregulates RPS9A expression, impairing the timely expression of RPS9 during meiosis. Complete deletion of RPS9A impairs the expression pattern of meiotic genes and inhibits sporulation in yeast. These findings suggest a regulatory strategy whereby transcription factors modulate the splicing of duplicated ribosomal protein genes to fine-tune their expression in different cellular states.

Proteomic analysis reveals the difference between the spermatozoa of young and old Sus scrofa

The Wannan black pig is a superior local breed in Anhui province, renowned for its exceptional meat quality and remarkable adaptability to various environmental conditions. Semen, being a crucial indicator of male sexual maturity and fertility, significantly influences the performance of breeding boars. The molecular basis for comprehending the fecundity of boars in practical production lies in understanding the disparities in sperm proteins among boars of varying ages. In this investigation, spermatozoa from three one-year-old and three seven-year-old Wannan black pigs were individually chosen. Employing a tandem mass tag (TMT)-based quantitative proteomics approach, a total of 4050 proteins were identified, out of which 130 proteins exhibited significant differences between the two groups. GO enrichment analysis revealed that these proteins primarily participated in energy metabolism, spermatogenesis, fertilization, and reproduction. KEGG enrichment analysis demonstrated that the differential proteins predominantly resided within the ribosome pathway. A protein-protein interaction (PPI) network was constructed to identify core proteins such as Small ribosomal subunit protein uS7 (RPS5). Ultimately, parallel reaction monitoring (PRM) was conducted on the selected differential proteins to validate result accuracy. The findings of this study establish a foundation for elucidating the molecular mechanism underlying variations in spermatozoa protein levels among Wannan Black Pig with different age.

The CDK8 kinase module: A novel player in the transcription of translation initiation and ribosomal genes

Survival following stress is dependent upon reprogramming transcription and translation. Communication between these programs following stress is critical for adaptation but is not clearly understood. The Cdk8 kinase module (CKM) of the Mediator complex modulates the transcriptional response to various stresses. Its involvement in regulating translational machinery has yet to be elucidated, highlighting an existing gap in knowledge. Here, we report that the CKM positively regulates a subset of ribosomal protein (RP) and translation initiation factor (TIF)-encoding genes under physiological conditions in Saccharomyces cerevisiae. In mouse embryonic fibroblasts and HCT116 cells, the CKM regulates unique sets of RP and TIF genes, demonstrating some conservation of function across species. In yeast, this is mediated by Cdk8 phosphorylation of one or more transcription factors which control RP and TIF expression. Conversely, the CKM is disassembled following nutrition stress, permitting repression of RP and TIF genes. The CKM also plays a transcriptional role important for promoting cell survival, particularly during translational machinery stress triggered by ribosome-targeting antibiotics. Furthermore, in mammalian cells, the activity of CDK8 and its paralogue, CDK19, promotes cell survival following ribosome inhibition. These results provide mechanistic insights into the CKM's role in regulating expression of a subset of genes associated with translation.

In-silico identification of putatively functional intergenic small open reading frames in the cucumber genome and their predicted response to biotic and abiotic stresses

The availability of high-throughput sequencing technologies increased our understanding of different genomes. However, the genomes of all living organisms still have many unidentified coding sequences. The increased number of missing small open reading frames (sORFs) is due to the length threshold used in most gene identification tools, which is true in the genic and, more importantly and surprisingly, in the intergenic regions. Scanning the cucumber genome intergenic regions revealed 420 723 sORF. We excluded 3850 sORF with similarities to annotated cucumber proteins. To propose the functionality of the remaining 416 873 sORF, we calculated their codon adaptation index (CAI). We found 398 937 novel sORF (nsORF) with CAI ≥ 0.7 that were further used for downstream analysis. Searching against the Rfam database revealed 109 nsORFs similar to multiple RNA families. Using SignalP-5.0 and NLS, identified 11 592 signal peptides. Five predicted proteins interacting with Meloidogyne incognita and Powdery mildew proteins were selected using published transcriptome data of host-pathogen interactions. Gene ontology enrichment interpreted the function of those proteins, illustrating that nsORFs' expression could contribute to the cucumber's response to biotic and abiotic stresses. This research highlights the importance of previously overlooked nsORFs in the cucumber genome and provides novel insights into their potential functions.

Ageing-associated long non-coding RNA extends lifespan and reduces translation in non-dividing cells

Genomes produce widespread long non-coding RNAs (lncRNAs) of largely unknown functions. We characterize aal1 (ageing-associated lncRNA), which is induced in quiescent fission yeast cells. Deletion of aal1 shortens the chronological lifespan of non-dividing cells, while ectopic overexpression prolongs their lifespan, indicating that aal1 acts in trans. Overexpression of aal1 represses ribosomal-protein gene expression and inhibits cell growth, and aal1 genetically interacts with coding genes functioning in protein translation. The aal1 lncRNA localizes to the cytoplasm and associates with ribosomes. Notably, aal1 overexpression decreases the cellular ribosome content and inhibits protein translation. The aal1 lncRNA binds to the rpl1901 mRNA, encoding a ribosomal protein. The rpl1901 levels are reduced ~2-fold by aal1, which is sufficient to extend lifespan. Remarkably, the expression of the aal1 lncRNA in Drosophila boosts fly lifespan. We propose that aal1 reduces the ribosome content by decreasing Rpl1901 levels, thus attenuating the translational capacity and promoting longevity. Although aal1 is not conserved, its effect in flies suggests that animals feature related mechanisms that modulate ageing, based on the conserved translational machinery.

Assembly and comparative analysis of the first complete mitochondrial genome of Salix psammophila, a good windbreak and sand fixation shrub

Salix psammophila, commonly known as the sandlive willow, is a vital shrub species within the Salicaceae family, particularly significant for its ecological role in regions susceptible to desertification and sandy soils. In this study, we assembled the complete S. psammophila mitochondrial genome using Pacbio HiFi third-generation sequencing data. The genome was found to be a typical single circular structure, with a total length of 715,555 bp and a GC content of 44.89%. We annotated 33 unique protein-coding genes (PCGs), which included 24 core mitochondrial genes and 9 variable genes, as well as 18 tRNA genes (5 of which were multicopy genes) and 3 rRNA genes. Comparative analysis of the PCGs from the mitochondrial genomes of S. psammophila, Populus deltoides, Populus simonii, Salix wilsonii, and Salix suchowensis revealed that these genes are relatively conserved within the Salicaceae family, with variability primarily occurring in the ribosomal protein genes. The absence of the rps14, which encodes a ribosomal protein, may have played a role in the evolution of stress tolerance in Salicaceae plants. Additionally, we identified 232 SSRs, 19 tandem repeat sequences, and 236 dispersed repeat sequences in the S. psammophila mitochondrial genome, with palindromic and forward repeats being the most abundant. The longest palindromic repeat measured 260 bp, while the longest forward repeat was 86,068 bp. Furthermore, 324 potential RNA editing sites were discovered, all involving C-to-U edits, with the nad4 having the highest number of edits. These findings provide valuable insights into the phylogenetic and genetic research of Salicaceae plants.

Identification and validation of reference genes for RT-qPCR analysis in Sclerodermus guani (Hymenoptera: Bethylidae)

Gene expression studies in organisms are often conducted using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR), and the accuracy of RT-qPCR results relies on the stability of reference genes. We examined ten candidate reference genes in Sclerodermus guani, a parasitoid wasp that is a natural enemy of long-horned beetle pests in forestry, including ACT, EF1α, Hsc70, Hsp70, SRSF7, α-tubulin, RPL7A, 18S, 28S, and SOD1, regarding variable biotic and abiotic factors such as body part, life stage, hormone, diet, and temperature. Data were analysed using four dedicated algorithms (ΔCt, BestKeeper, NormFinder, and geNorm) and one comparative tool (RefFinder). Our results showed that the most stable reference genes were RPL7A and EF1α regarding the body part, SRSF7 and Hsc70 regarding the diet, RPL7A and α-tubulin regarding the hormone, SRSF7 and RPL7A regarding the life stage, and SRSF7 and α-tubulin regarding temperature. To ascertain the applicability of specific reference genes, the expression level of the target gene (ACPase) was estimated regarding the body part using the most stable reference genes, RPL7A and EF1α, and the least stable one, SOD1. The highest expression level of ACPase was observed in the abdomen, and the validity of RPL7A and EF1α was confirmed. This study provides, for the first time, an extensive list of reliable reference genes for molecular biology studies in S. guani.

Transcriptomic evaluation of metals detected in placenta

This research aims to assess the concentration of metals in human and canine placentas from the same geographic area and to investigate how these metal levels influence gene expression within the placenta. Placentas of 25 dogs and 60 women who had recently given birth residing in Ankara, Turkey were collected and subjected to metal analysis using ICP-OES. Placentas with detectable metal levels underwent further examination including Next Generation Sequencing, transcriptional analysis, single nucleotide polymorphism investigation, and extensive scrutiny across various groups. For women, placentas with concurrent detection of aluminum (Al), lead (Pb), and cadmium (Cd) underwent transcriptomic analysis based on metal analysis results. However, the metal load in dog placentas was insufficient for comparison. Paired-end sequencing with 100-base pair read lengths was conducted using the DNBseq platform. Sequencing quality control was evaluated using FastQC, fastq screen, and MultiQC. RNA-sequencing data is publicly available via PRJNA936158. Comparative analyses were performed between samples with detected metals and "golden" samples devoid of these metals, revealing significant gene lists and read counts. Normalization of read counts was based on estimated size factors. Principal Component Analysis (PCA) was applied to all genes using rlog-transformed count data. Results indicate that metal exposure significantly influences placental gene expression, impacting various biological processes and pathways, notably those related to protein synthesis, immune responses, and cellular structure. Upregulation of immune-related pathways and alterations in protein synthesis machinery suggest potential defense mechanisms against metal toxicity. Nonetheless, these changes may adversely affect placental function and fetal health, emphasizing the importance of monitoring and mitigating environmental exposure to metals during pregnancy.

Evaluation of Reference Gene Stability in Goat Skeletal Muscle Satellite Cells during Proliferation and Differentiation Phases

The process of skeletal muscle development is intricate and involves the regulation of a diverse array of genes. Accurate gene expression profiles are crucial for studying muscle development, making it essential to choose the right reference genes for real-time quantitative PCR (RT-qPCR). In the present study, eight candidate reference genes were identified from our previous transcriptome sequencing analysis of caprine skeletal muscle satellite cells (MuSCs), and two traditional reference genes (ACTB and GAPDH) were assessed. The quantitative levels of the candidate reference genes were determined through the RT-qPCR technique, while the stability of their expression was evaluated utilizing the GeNorm, NormFinder, BestKeeper, and RefFinder programs. Furthermore, the chosen reference genes were utilized for the normalization of the gene expression levels of PCNA and Myf5. It was determined that conventional reference genes, including ACTB and GAPDH, were not appropriate for normalizing target gene expression. Conversely, RPL14 and RPS15A, identified through RNA sequencing analysis, exhibited minimal variability and were identified as the optimal reference genes for normalizing gene expression during the proliferation and differentiation of goat MuSCs. Our research offers a validated panel of optimal reference genes for the detection of differentially expressed genes in goat muscle satellite cells using RT-qPCR.

Ribosome Profiling and RNA Sequencing Reveal Translation and Transcription Regulation under Acute Heat Stress in Rainbow Trout (Oncorhynchus mykiss, Walbaum, 1792) Liver

Rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) is an important economic cold-water fish that is susceptible to heat stress. To date, the heat stress response in rainbow trout is more widely understood at the transcriptional level, while little research has been conducted at the translational level. To reveal the translational regulation of heat stress in rainbow trout, in this study, we performed a ribosome profiling assay of rainbow trout liver under normal and heat stress conditions. Comparative analysis of the RNA-seq data with the ribosome profiling data showed that the folding changes in gene expression at the transcriptional level are moderately correlated with those at the translational level. In total, 1213 genes were significantly altered at the translational level. However, only 32.8% of the genes were common between both levels, demonstrating that heat stress is coordinated across both transcriptional and translational levels. Moreover, 809 genes exhibited significant differences in translational efficiency (TE), with the TE of these genes being considerably affected by factors such as the GC content, coding sequence length, and upstream open reading frame (uORF) presence. In addition, 3468 potential uORFs in 2676 genes were identified, which can potentially affect the TE of the main open reading frames. In this study, Ribo-seq and RNA-seq were used for the first time to elucidate the coordinated regulation of transcription and translation in rainbow trout under heat stress. These findings are expected to contribute novel data and theoretical insights to the international literature on the thermal stress response in fish.

Deciphering deep-sea chemosynthetic symbiosis by single-nucleus RNA-sequencing

Bathymodioline mussels dominate deep-sea methane seep and hydrothermal vent habitats and obtain nutrients and energy primarily through chemosynthetic endosymbiotic bacteria in the bacteriocytes of their gill. However, the molecular mechanisms that orchestrate mussel host-symbiont interactions remain unclear. Here, we constructed a comprehensive cell atlas of the gill in the mussel Gigantidas platifrons from the South China Sea methane seeps (1100 m depth) using single-nucleus RNA-sequencing (snRNA-seq) and whole-mount in situ hybridisation. We identified 13 types of cells, including three previously unknown ones, and uncovered unknown tissue heterogeneity. Every cell type has a designated function in supporting the gill's structure and function, creating an optimal environment for chemosynthesis, and effectively acquiring nutrients from the endosymbiotic bacteria. Analysis of snRNA-seq of in situ transplanted mussels clearly showed the shifts in cell state in response to environmental oscillations. Our findings provide insight into the principles of host-symbiont interaction and the bivalves' environmental adaption mechanisms.

Promoted Read-through and Mutation Against Pseudouridine-CMC by an Evolved Reverse Transcriptase

Pseudouridine (Ψ) is an abundant RNA chemical modification that can play critical roles in the biological functions of RNA, and RNA-therapeutic applications. Current Ψ detection methods are limited in identifying Ψs at base-resolution in U-rich sequence contexts, where Ψ occurs frequently. The N-cyclohexyl N'-(2-morpholinoethyl)carbodiimide (CMC) can selectively label Ψ in RNA by forming the CMC-Ψ adduct. Here we report that an evolved reverse transcriptase ("RT-1306") shows promoted read-through and mutation against the CMC-Ψ. The mutation signature can resolve the occurrence of Ψs within UU-containing sequences. We developed "Mut-Ψ-seq" utilizing CMC and RT-1306 for transcriptome-wide mapping of Ψ at base-resolution. The mutation signatures robustly identify reported Ψs in human rRNAs via the ROC analysis, and elongated CMC reaction duration increases the detection sensitivity of Ψ. We report a high-confidence list of Ψ sites in polyA-enriched RNAs from HEK-293T cells identified by orthogonal chemical treatments (CMC and bisulfite). The mutation signatures resolve the position of Ψ in UU-containing sequences, revealing diverse occurrence of Ψs in such sequences. This work provides new methods and datasets for biological research of Ψ, and demonstrates the potential of combining the reverse transcriptase engineering and selective chemical labeling to expand the toolkit for RNA chemical modifications studies.

Resolving candidate genes of duck ovarian tissue transplantation via RNA-Seq and expression network analyses

This study aims to identify candidate genes related to ovarian development after ovarian tissue transplantation through transcriptome sequencing (RNA-seq) and expression network analyses, as well as to provide a reference for determining the molecular mechanism of improving ovarian development following ovarian tissue transplantation. We collected ovarian tissues from 15 thirty-day-old ducks and split each ovary into 4 equal portions of comparable sizes before orthotopically transplanting them into 2-day-old ducks. Samples were collected on days 0 (untransplanted), 3, 6, and 9. The samples were paraffin sectioned and then subjected to Hematoxylin-Eosin (HE) staining and follicular counting. We extracted RNA from ovarian samples via the Trizol method to construct a transcriptome library, which was then sequenced by the Illumina Novaseq 6000 sequencing platform. The sequencing results were examined for differentially expressed genes (DEG) through gene ontology (GO) function and the Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses, gene set enrichment analysis (GSEA), weighted correlation network analysis (WGCNA), and protein-protein interaction (PPI) networks. Some of the candidate genes were selected for verification using real-time fluorescence quantitative PCR (qRT-PCR). Histological analysis revealed a significant reduction in the number of morphologically normal follicles at 3, 6, and 9 d after ovarian transplantation, along with significantly higher abnormality rates (P < 0.05). The transcriptome analysis results revealed 2,114, 2,224, and 2,257 upregulated DEGs and 2,647, 2,883, and 2,665 downregulated DEGs at 3, 6, and 9 d after ovarian transplantation, respectively. Enrichment analysis revealed the involvement multiple pathways in inflammatory signaling, signal transduction, and cellular processes. Furthermore, WGCNA yielded 13 modules, with 10, 4, and 6 candidate genes mined at 3, 6 and 9 d after ovarian transplantation, respectively. Transcription factor (TF) prediction showed that STAT1 was the most important TF. Finally, the qRT-PCR verification results revealed that 12 candidate genes exhibited an expression trend consistent with sequencing data. In summary, significant differences were observed in the number of follicles in duck ovaries following ovarian transplantation. Candidate genes involved in ovarian vascular remodeling and proliferation were screened using RNA-Seq and WGCNA.

Computational single-cell methods for predicting cancer risk

Despite recent biotechnological breakthroughs, cancer risk prediction remains a formidable computational and experimental challenge. Addressing it is critical in order to improve prevention, early detection and survival rates. Here, I briefly summarize some key emerging theoretical and computational challenges as well as recent computational advances that promise to help realize the goals of cancer-risk prediction. The focus is on computational strategies based on single-cell data, in particular on bottom-up network modeling approaches that aim to estimate cancer stemness and dedifferentiation at single-cell resolution from a systems-biological perspective. I will describe two promising methods, a tissue and cell-lineage independent one based on the concept of diffusion network entropy, and a tissue and cell-lineage specific one that uses transcription factor regulons. Application of these tools to single-cell and single-nucleus RNA-seq data from stages prior to invasive cancer reveal that they can successfully delineate the heterogeneous inter-cellular cancer-risk landscape, identifying those cells that are more likely to turn cancerous. Bottom-up systems biological modeling of single-cell omic data is a novel computational analysis paradigm that promises to facilitate the development of preventive, early detection and cancer-risk prediction strategies.

Regulation of the Drosophila transcriptome by Pumilio and the CCR4-NOT deadenylase complex

The sequence-specific RNA-binding protein Pumilio (Pum) controls Drosophila development; however, the network of mRNAs that it regulates remains incompletely characterized. In this study, we use knockdown and knockout approaches coupled with RNA-seq to measure the impact of Pum on the transcriptome of Drosophila cells in culture. We also use an improved RNA coimmunoprecipitation method to identify Pum-bound mRNAs in Drosophila embryos. Integration of these data sets with the locations of Pum-binding motifs across the transcriptome reveals novel direct Pum target genes involved in neural, muscle, wing, and germ cell development and in cellular proliferation. These genes include components of Wnt, TGF-β, MAPK/ERK, and Notch signaling pathways, DNA replication, and lipid metabolism. We identify the mRNAs regulated by the CCR4-NOT deadenylase complex, a key factor in Pum-mediated repression, and observe concordant regulation of Pum:CCR4-NOT target mRNAs. Computational modeling reveals that Pum binding, binding site number, clustering, and sequence context are important determinants of regulation. In contrast, we show that the responses of direct mRNA targets to Pum-mediated repression are not influenced by the content of optimal synonymous codons. Moreover, contrary to a prevailing model, we do not detect a role for CCR4-NOT in the degradation of mRNAs with low codon optimality. Together, the results of this work provide new insights into the Pum regulatory network and mechanisms and the parameters that influence the efficacy of Pum-mediated regulation.

Proteotranscriptomic analyses of the midgut and Malpighian tubules after a sublethal concentration of Cry1Ab exposure on Spodoptera litura

BACKGROUND

Cry1Ab has emerged as a bio-insecticide to control Spodoptera litura (Lepidoptera: Noctuidae). However, the sublethal effects of Cry1Ab on the physiological changes and molecular level of S. litura have not been well documented. Our aims in this study were to assess the sublethal effect of Cry1Ab on S. litura, including midgut and Malpighian tubules as targets.

RESULTS

After sublethal Cry1Ab exposure, distinct histological alterations were mainly observed in the midgut. Furthermore, the results of comparative RNA sequencing and tandem mass tag-based proteomics showed that, in the midgut, most differential expression genes (DEGs) were up-regulated and significantly enriched in the serine protease activity pathway, and up-regulated differential expression proteins (DEPs) were mainly associated with the oxidative phosphorylation pathway, whereas the down-regulated involved in the ribosome pathways. In the Malpighian tubules, DEGs and DEPs were significantly enriched in the ribosome pathway. We proposed that ribosome may act as a universal target in energy metabolism with other pathways via the results of protein-protein interaction analysis. Further, by verification of the mRNA expression of some Cry protein receptor and detoxification genes after Cry1Ab treatment, it was suggested that the ribosomal proteins (RPs) possibly participate in influencing the Bt-resistance of S. litura larvae under sublethal Cry1Ab exposure.

CONCLUSION

Under sublethal Cry1Ab exposure, the midgut of S. litura was damaged, and the proteotranscriptomic analysis elucidated that Cry1Ab disrupted the energy homeostasis of larvae. Furthermore, we emphasized the potential role of ribosomes in sublethal Cry1Ab exposure. © 2024 Society of Chemical Industry.

IRX5 suppresses osteogenic differentiation of hBMSCs by inhibiting protein synthesis

In our previous study, IRX5 has been revealed a significant role in adipogenesis of hBMSCs. Considering the expansion of adipose tissue in bone marrow in aged and ovariectomy-related osteoporosis, the effect of IRX5 on the osteogenesis of BMSCs still needs to be elucidated. In vivo, models of aging-induced and ovariectomy-induced osteoporotic mice, and in vitro studies of IRX5 gene gain- and loss-of-function in hBMSCs were employed. Histology, immunofluorescence, qRT-PCR, and Western blot analysis were performed to detect the functions of IRX5 in hBMSCs osteogenic differentiation. RNA-seq, transmission electron microscopy, Seahorse mito-stress assay, and Surface Sensing of Translation assay were conducted to explore the effect of mammalian/mechanistic target of rapamycin (mTOR)-mediated ribosomal translation and mitochondrial functions in the regulation of hBMSCs differentiation by IRX5. As a result, elevated IRX5 protein expression levels were observed in the bone marrow of osteoporotic mice compared to normal mice. IRX5 overexpression attenuated osteogenic processes, whereas IRX5 knockdown resulted in enhanced osteogenesis in hBMSCs. RNA-seq and enrichment analysis unveiled that IRX5 overexpression exerted inhibitory effects on ribosomal translation and mitochondrial functions. Furthermore, the application of the mTOR activator, MHY1485, effectively reversed the inhibitory impact of IRX5 on osteogenesis and mitochondrial functions in hBMSCs. In summary, our findings suggest that IRX5 restricts mTOR-mediated ribosomal translation, consequently impairing mitochondrial OxPhos, which in turn results in osteogenic dysfunction of hBMSCs.

The discovery of novel noncoding RNAs in 50 bacterial genomes

Structured noncoding RNAs (ncRNAs) contribute to many important cellular processes involving chemical catalysis, molecular recognition and gene regulation. Few ncRNA classes are broadly distributed among organisms from all three domains of life, but the list of rarer classes that exhibit surprisingly diverse functions is growing. We previously developed a computational pipeline that enables the near-comprehensive identification of structured ncRNAs expressed from individual bacterial genomes. The regions between protein coding genes are first sorted based on length and the fraction of guanosine and cytidine nucleotides. Long, GC-rich intergenic regions are then examined for sequence and structural similarity to other bacterial genomes. Herein, we describe the implementation of this pipeline on 50 bacterial genomes from varied phyla. More than 4700 candidate intergenic regions with the desired characteristics were identified, which yielded 44 novel riboswitch candidates and numerous other putative ncRNA motifs. Although experimental validation studies have yet to be conducted, this rate of riboswitch candidate discovery is consistent with predictions that many hundreds of novel riboswitch classes remain to be discovered among the bacterial species whose genomes have already been sequenced. Thus, many thousands of additional novel ncRNA classes likely remain to be discovered in the bacterial domain of life.

High-throughput quantitation of protein-RNA UV-crosslinking efficiencies as a predictive tool for high-confidence identification of RNA-binding proteins

UV-crosslinking has proven to be an invaluable tool for the identification of RNA-protein interactomes. The paucity of methods for distinguishing background from bona fide RNA-protein interactions, however, makes attribution of RNA-binding function on UV-crosslinking alone challenging. To address this need, we previously reported an RNA-binding protein (RBP) confidence scoring metric (RCS), incorporating both signal-to-noise (S:N) and protein abundance determinations to distinguish high- and low-confidence candidate RBPs. Although RCS has utility, we sought a direct metric for quantification and comparative evaluation of protein-RNA interactions. Here we propose the use of protein-specific UV-crosslinking efficiency (%CL), representing the molar fraction of a protein that is crosslinked to RNA, for functional evaluation of candidate RBPs. Application to the HeLa RNA interactome yielded %CL values for 1097 proteins. Remarkably, %CL values span over five orders of magnitude. For the HeLa RNA interactome, %CL values comprise a range from high efficiency, high specificity interactions, e.g., the Elav protein HuR and the Pumilio homolog Pum2, with %CL values of 45.9 and 24.2, respectively, to very low efficiency and specificity interactions, for example, the metabolic enzymes glyceraldehyde-3-phosphate dehydrogenase, fructose-bisphosphate aldolase, and alpha-enolase, with %CL values of 0.0016, 0.006, and 0.008, respectively. We further extend the utility of %CL through prediction of protein domains and classes with known RNA-binding functions, thus establishing it as a useful metric for RNA interactome analysis. We anticipate that this approach will benefit efforts to establish functional RNA interactomes and support the development of more predictive computational approaches for RBP identification.

Leishmania Ribosomal Protein (RP) paralogous genes compensate each other's expression maintaining protein native levels

In the protozoan parasite Leishmania, most genes encoding for ribosomal proteins (RPs) are present as two or more copies in the genome. However, their untranslated regions (UTRs) are predominantly divergent and might be associated with a distinct regulation of the expression of paralogous genes. Herein, we investigated the expression profiles of two RPs (S16 and L13a) encoded by duplicated genes in Leishmania major. The genes encoding for the S16 protein possess identical coding sequences (CDSs) and divergent UTRs, whereas the CDSs of L13a diverge by two amino acids and by their UTRs. Using CRISPR/Cas9 genome editing, we generated knockout (Δ) and endogenously tagged transfectants for each paralog of L13a and S16 genes. Combining tagged and Δ cell lines we found evidence of differential expression of both RPS16 and RPL13a isoforms throughout parasite development, with one isoform consistently more abundant than its respective copy. In addition, compensatory expression was observed for each paralog upon deletion of the corresponding isoform, suggesting functional conservation between these proteins. This differential expression pattern relates to post-translational processes, given compensation occurs at the level of the protein, with no alterations detected at transcript level. Ribosomal profiles for RPL13a indicate a standard behavior for these paralogues suggestive of interaction with heavy RNA-protein complexes, as already reported for other RPs in trypanosomatids. We identified paralog-specific bound to their 3'UTRs which may be influential in regulating paralog expression. In support, we identified conserved cis-elements within the 3'UTRs of RPS16 and RPL13a; cis-elements exclusive to the UTR of the more abundant paralog or to the less abundant ones were identified.

Construction of dental pulp decellularized matrix by cyclic lavation combined with mechanical stirring and its proteomic analysis

The decellularized matrix has a great potential for tissue remodeling and regeneration; however, decellularization could induce host immune rejection due to incomplete cell removal or detergent residues, thereby posing significant challenges for its clinical application. Therefore, the selection of an appropriate detergent concentration, further optimization of tissue decellularization technique, increased of biosafety in decellularized tissues, and reduction of tissue damage during the decellularization procedures are pivotal issues that need to be investigated. In this study, we tested several conditions and determined that 0.1% Sodium dodecyl sulfate and three decellularization cycles were the optimal conditions for decellularization of pulp tissue. Decellularization efficiency was calculated and the preparation protocol for dental pulp decellularization matrix (DPDM) was further optimized. To characterize the optimized DPDM, the microstructure, odontogenesis-related protein and fiber content were evaluated. Our results showed that the properties of optimized DPDM were superior to those of the non-optimized matrix. We also performed the 4D-Label-free quantitative proteomic analysis of DPDM and demonstrated the preservation of proteins from the natural pulp. This study provides a optimized protocol for the potential application of DPDM in pulp regeneration.

The stringent response is strongly activated in the antibiotic producing strain, Streptomyces coelicolor

S. lividans and S. coelicolor are phylogenetically closely related strains with different abilities to produce the same specialized metabolites. Previous studies revealed that the strong antibiotic producer, S. coelicolor, had a lower ability to assimilate nitrogen and phosphate than the weak producer, Streptomyces lividans, and this resulted into a lower growth rate. A comparative proteomic dataset was used to establish the consequences of these nutritional stresses on the abundance of proteins of the translational apparatus of these strains, grown in low and high phosphate availability. Our study revealed that most proteins of the translational apparatus were less abundant in S. coelicolor than in S. lividans whereas it was the opposite for ET-Tu 3 and a TrmA-like methyltransferase. The expression of the latter being known to be under the positive control of the stringent response whereas that of the other ribosomal proteins is under its negative control, this indicated the occurrence of a strong activation of the stringent response in S. coelicolor. Furthermore, in S. lividans, ribosomal proteins were more abundant in phosphate proficiency than in phosphate limitation suggesting that a limitation in phosphate, that was also shown to trigger RelA expression, contributes to the induction of the stringent response.

Macromolecular crowding in human tenocyte and skin fibroblast cultures: A comparative analysis

Although human tenocytes and dermal fibroblasts have shown promise in tendon engineering, no tissue engineered medicine has been developed due to the prolonged ex vivo time required to develop an implantable device. Considering that macromolecular crowding has the potential to substantially accelerate the development of functional tissue facsimiles, herein we compared human tenocyte and dermal fibroblast behaviour under standard and macromolecular crowding conditions to inform future studies in tendon engineering. Basic cell function analysis made apparent the innocuousness of macromolecular crowding for both cell types. Gene expression analysis of the without macromolecular crowding groups revealed expression of tendon related molecules in human dermal fibroblasts and tenocytes. Protein electrophoresis and immunocytochemistry analyses showed significantly increased and similar deposition of collagen fibres by macromolecular crowding in the two cell types. Proteomics analysis demonstrated great similarities between human tenocyte and dermal fibroblast cultures, as well as the induction of haemostatic, anti-microbial and tissue-protective proteins by macromolecular crowding in both cell populations. Collectively, these data rationalise the use of either human dermal fibroblasts or tenocytes in combination with macromolecular crowding in tendon engineering.

Transcriptomic changes behind Sparus aurata hepatic response to different aquaculture challenges: An RNA-seq study and multiomics integration

Gilthead seabream (Sparus aurata) is an important species in Mediterranean aquaculture. Rapid intensification of its production and sub-optimal husbandry practices can cause stress, impairing overall fish performance and raising issues related to sustainability, animal welfare, and food safety. The advent of next-generation sequencing technologies has greatly revolutionized the study of fish stress biology, allowing a deeper understanding of the molecular stress responses. Here, we characterized for the first time, using RNA-seq, the different hepatic transcriptome responses of gilthead seabream to common aquaculture challenges, namely overcrowding, net handling, and hypoxia, further integrating them with the liver proteome and metabolome responses. After reference-guided transcriptome assembly, annotation, and differential gene expression analysis, 7, 343, and 654 genes were differentially expressed (adjusted p-value < 0.01, log2|fold-change| >1) in the fish from the overcrowding, net handling, and hypoxia challenged groups, respectively. Gene set enrichment analysis (FDR < 0.05) suggested a scenario of challenge-specific responses, that is, net handling induced ribosomal assembly stress, whereas hypoxia induced DNA replication stress in gilthead seabream hepatocytes, consistent with proteomics and metabolomics' results. However, both responses converged upon the downregulation of insulin growth factor signalling and induction of endoplasmic reticulum stress. These results demonstrate the high phenotypic plasticity of this species and its differential responses to distinct challenging environments at the transcriptomic level. Furthermore, it provides significant resources for characterizing and identifying potentially novel genes that are important for gilthead seabream resilience and aquaculture production efficiency with regard to fish welfare.

Ribosomal protein SA is a common component of neuronal intranuclear inclusions in polyglutamine diseases and Marinesco bodies

Neuronal intranuclear inclusions (NIIs) are common key structures in polyglutamine (polyQ) diseases such as Huntington disease (HD), spinocerebellar ataxia type 1 (SCA1), and SCA3. Marinesco bodies (MBs) of dopaminergic neurons in the substantia nigra are also intranuclear structures and are frequently seen in normal elderly people. Ribosomal dysfunction is closely related to two differential processes; therefore, we aimed to identify the pathological characteristics of ribosomal protein SA (RPSA), a ribosomal protein, in both states. To this end, we evaluated the autopsy findings in four patients with HD, two SCA3, and five normal elderly cases (NCs). Immunohistochemical studies demonstrated that both NIIs and MBs contain RPSA. In polyQ diseases, RPSA was co-localized with polyQ aggregations, and 3D-reconstructed images revealed their mosaic-like distribution. Assessments of the organization of RPSA and p62 in NIIs showed that RPSA was more localized toward the center than p62 and that this unique organization was more evident in the MBs. Immunoblotting of the temporal cortices revealed that the nuclear fraction of HD patients contained more RPSA than that of NCs. In conclusion, our study revealed that RPSA is a common component of both NIIs and MBs, indicating that a similar mechanism contributes to the formation of polyQ NIIs and MBs.

Remodeling of the human skeletal muscle proteome found after long-term endurance training but not after strength training

Exercise training has tremendous systemic tissue-specific health benefits, but the molecular adaptations to long-term exercise training are not completely understood. We investigated the skeletal muscle proteome of highly endurance-trained, strength-trained, and untrained individuals and performed exercise- and sex-specific analyses. Of the 6,000+ proteins identified, >650 were differentially expressed in endurance-trained individuals compared with controls. Strikingly, 92% of the shared proteins with higher expression in both the male and female endurance groups were known mitochondrial. In contrast to the findings in endurance-trained individuals, minimal differences were found in strength-trained individuals and between females and males. Lastly, a co-expression network and comparative literature analysis revealed key proteins and pathways related to the health benefits of exercise, which were primarily related to differences in mitochondrial proteins. This network is available as an interactive database resource where investigators can correlate clinical data with global gene and protein expression data for hypothesis generation.

Role of RNA polymerase III transcription and regulation in ischaemic stroke

Ischaemic stroke is a leading cause of death and life-long disability due to neuronal cell death resulting from interruption of glucose and oxygen supplies. RNA polymerase III (Pol III)-dependent transcription plays a central role in protein synthesis that is necessary for normal cerebral neuronal functions, and the survival and recovery under pathological conditions. Notably, Pol III transcription is highly sensitive to ischaemic stress that is known to rapidly shut down Pol III transcriptional activity. However, its precise role in ischaemic stroke, especially during the acute and recovery phases, remains poorly understood. The microenvironment within the ischaemic brain undergoes dynamic changes in different phases after stroke. Emerging evidence highlights the distinct roles of Pol III transcription in neuroprotection during the acute phase and repair during the recovery phase of stroke. Additionally, investigations into the mTOR-MAF1 signalling pathway, a conserved regulator of Pol-III transcription, reveal its therapeutic potential in enhancing acute phase neuroprotection and recovery phase repair.

Identification of stable reference genes for relative quantification of long RNA expression in urinary extracellular vesicles

Urinary extracellular vesicles (uEVs) are rich in valuable biomolecule information which are increasingly recognized as potential biomarkers for various diseases. uEV long RNAs are among the critical cargos capable of providing unique transcriptome information of the source cells. However, consensus regarding ideal reference genes for relative long RNAs quantification in uEVs is not available as of date. Here we explored stable reference genes through profiling the long RNA expression by RNA-seq following unsupervised analysis and validation studies. Candidate reference genes were identified using four algorithms: NormFinder, GeNorm, BestKeeper and the Delta Ct method, followed by validation. RNA profile showed uEVs contained abundant long RNAs information and the core transcriptome was related to cellular structures, especially ribosome which functions mainly as translation, protein and RNA binding molecules. Analysis of RNA-seq data identified RPL18A, RPL11, RPL27, RACK1, RPSA, RPL41, H1-2, RPL4, GAPDH, RPS27A as candidate reference genes. RT-qPCR validation revealed that RPL41, RPSA and RPL18A were reliable reference genes for long RNA quantification in uEVs from patients with diabetes mellitus (DM), diabetic nephropathy (DN), IgA nephropathy (IgAN) and prostate cancer (PCA). Interestingly, RPL41 also outperformed traditional reference genes in renal tissues of DN and IgAN, as well as in plasma EVs of several types of cancers. The stable reference genes identified in this study may facilitate development of uEVs as novel biomarkers and increase the accuracy and comparability of biomarker studies.

Loss of the DYRK1A Protein Kinase Results in the Reduction in Ribosomal Protein Gene Expression, Ribosome Mass and Reduced Translation

Ribosomal proteins (RPs) are evolutionary conserved proteins that are essential for protein translation. RP expression must be tightly regulated to ensure the appropriate assembly of ribosomes and to respond to the growth demands of cells. The elements regulating the transcription of RP genes (RPGs) have been characterized in yeast and Drosophila, yet how cells regulate the production of RPs in mammals is less well understood. Here, we show that a subset of RPG promoters is characterized by the presence of the palindromic TCTCGCGAGA motif and marked by the recruitment of the protein kinase DYRK1A. The presence of DYRK1A at these promoters is associated with the enhanced binding of the TATA-binding protein, TBP, and it is negatively correlated with the binding of the GABP transcription factor, establishing at least two clusters of RPGs that could be coordinately regulated. However, DYRK1A silencing leads to a global reduction in RPGs mRNAs, pointing at DYRK1A activities beyond those dependent on its chromatin association. Significantly, cells in which DYRK1A is depleted have reduced RP levels, fewer ribosomes, reduced global protein synthesis and a smaller size. We therefore propose a novel role for DYRK1A in coordinating the expression of genes encoding RPs, thereby controlling cell growth in mammals.

Trichothiodystrophy-associated MPLKIP maintains DBR1 levels for proper lariat debranching and ectodermal differentiation

The brittle hair syndrome Trichothiodystrophy (TTD) is characterized by variable clinical features, including photosensitivity, ichthyosis, growth retardation, microcephaly, intellectual disability, hypogonadism, and anaemia. TTD-associated mutations typically cause unstable mutant proteins involved in various steps of gene expression, severely reducing steady-state mutant protein levels. However, to date, no such link to instability of gene-expression factors for TTD-associated mutations in MPLKIP/TTDN1 has been established. Here, we present seven additional TTD individuals with MPLKIP mutations from five consanguineous families, with a newly identified MPLKIP variant in one family. By mass spectrometry-based interaction proteomics, we demonstrate that MPLKIP interacts with core splicing factors and the lariat debranching protein DBR1. MPLKIP-deficient primary fibroblasts have reduced steady-state DBR1 protein levels. Using Human Skin Equivalents (HSEs), we observed impaired keratinocyte differentiation associated with compromised splicing and eventually, an imbalanced proteome affecting skin development and, interestingly, also the immune system. Our data show that MPLKIP, through its DBR1 stabilizing role, is implicated in mRNA splicing, which is of particular importance in highly differentiated tissue.