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Human m6A demethylase FTO modulates the flowering time of tomato plants under low-temperature stress.

N6-methyladenosine (m6A) RNA modification plays an important role in plant development and environmental stress responses. However, whether m6A demethylation modulates flowering under low-temperature (LT) stress in tomatoes remains unclear. Here, we investigated whether ectopic expression of FTO, a well-characterized human m6A demethylase, influences flowering and post-transcriptional behaviour in tomato (Solanum lycopersicum) under LT conditions. Flowering of transgenic tomato plants expressing FTO was analyzed under LT and normal conditions (NC), and the impacts of FTO on transcripts-specific m6A level, mRNA stability and splicing efficiency of flowering-related genes were evaluated using RT-qPCR, LC-MS/MS, m6A-IP-qPCR, and RNA decay and splicing analyses. FTO-expressing plants exhibited accelerated flowering specifically under LT, whereas no significant differences were observed under normal growth conditions. This phenotype was accompanied by increased expression of positive floral regulators (SlMC, SlFCA, and SlJ2) and decreased expression of negative regulators (SlSVP, SlSP, and SlTMF) under LT conditions. Notably, these expression changes were associated with altered mRNA stability, with positive regulators showing increased stability and negative regulators showing reduced stability under LT conditions. m6A-IP-qPCR analysis indicated reduced m6A enrichment in these selected transcripts in FTO-expressing plants. In addition to effects on mRNA stability, FTO expression was associated with changes in the splicing efficiency of SlMC transcripts. Collectively, our findings indicate that human FTO functions as an mRNA m6A demethylase in tomatoes and is associated with altered RNA regulatory processes under LT conditions. These findings suggest that m6A-mediated post-transcriptional regulation contributes to stress-induced flowering plasticity under LT conditions, rather than direct activation of canonical flowering pathways.

Abiotic stress

Functional Prediction of Epitranscriptome.

N6-methyladenosine (m6A) is one of the most prevalent and well-studied RNA modifications, playing a pivotal role in many biological processes. With the recent advances in high-throughput sequencing technologies, tens of thousands of m6A sites have been reported. However, not all m6A sites are important or functionally significant, highlighting the need to distinguish biologically relevant m6As from non-functional or technically artefactual ones. Here, we describe ConsRM, which is a web-based resource that was designed to evaluate the importance of m6As from an evolutionary perspective. It introduced a novel scoring framework for quantifying the conservation degree of m6As in humans. Its web interface includes a database of 177998 distinct human m6A sites along with their calculated conservation score, and allows users to analyze their own data via the web server. ConsRM is freely accessible at: http://180.208.58.19/conservation/browser.html .

Humans

Integrative quantum and systems biology of cancer: From molecular fluctuations to ecological outcomes.

This review treats cancer as a multiscale adaptive system, asks what the framework must predict to be worth adopting, and separates at each scale what the evidence establishes from what is proposed. It is an expert narrative synthesis, not a systematic review, and states the limits of that design. Proton transfer and tautomeric shifts contribute to spontaneous mispairing but do not license claims of directed or non-random mutation: replication timing, three-dimensional chromatin organization, sequence context and known mutagenic processes explain most mutational heterogeneity, leaving any quantum contribution as a residual against that baseline. The Waddington quasi-potential is bounded: outside detailed balance the dynamics are not gradient-derivable and require a probability-flux term. Hysteresis, rate-limited bimodality and return to state after perturbation distinguish an attractor from a transcriptomic cluster. Single-cell karyotype and live-imaging evidence supports whole-genome doubling as an unstable intermediate of heterogeneous origin and context-dependent consequence, not a uniform adaptive strategy. Systems and synthetic biology, virtual cells and digital twins are assessed against benchmarks, not promise. Tissue-scale ecology is reported with the spatial measurements now quantifying it, including evidence that stromal niche construction is not uniformly tumor-supporting. RNA modification is a layer in its own right, showing that the interpretation of a regulatory signal, not its magnitude, is biologically decisive. A dedicated section states the framework's commitments, the observable and evidence at each scale, and what would falsify them, asking what this adds to somatic mutation theory with clonal evolution and plasticity.

Neoplasms

Long noncoding RNAs and diabetic retinopathy: Current understanding, future directions and challenges.

Diabetic retinopathy remains as the leading cause of preventable blindness in working-aged people. The pathophysiology of this sight-threatening disease is complex and involves intricate interactions among metabolic, hemodynamic and epigenetic pathways, leading to molecular, structural, functional and genomic abnormalities in retinal vascular and nonvascular cells. Diabetes also results in differential expressions of several noncoding RNAs, including micro RNAs (miRNAs) and long noncoding RNAs (LncRNAs). Compared to about 2000 miRNA identified in human genome thus far, more than 30,000 LncRNA transcripts have been already identified, but the function and mechanism of action of most of the LncRNAs is still not fully characterized, and there remains a possibility that some LncRNAs could have diverse functions under different contexts. LncRNAs are mainly noncoding, but they have many regulatory functions, and regulate gene expression by interacting with DNA, RNA and protein. Aberrant expressions of several LncRNAs including MALAT1, MEG3, HOTAIR, MIAT1 and H19, is associated with metabolic abnormalities implicated in the pathogenesis of diabetic retinopathy. LncRNAs are also released into circulation and show high organ and cell specificity, and greater disease-associated differences compared to disease-associated mRNAs. Furthermore, LncRNAs maintain stable expression in the plasma and can be isolated from total RNA present in biological samples including blood, which makes them promising and reliable candidates for diagnostic or prognostic markers and therapeutic targets for various diseases. With continued improvement in innovative RNA modifications and delivery modalities, use of LncRNAs as possible biomarkers, and of LncRNA-based therapeutics, for diabetic retinopathy appears promising.

Biomarkers

FTO promotes weight gain via altering Kif1a splicing and axonal vesicle trafficking in AgRP neurons.

N6-methyladenosine (m6A) is an abundant chemical RNA modification involved in the regulation of many biological processes. The m6A demethylase FTO (fat mass and obesity-associated protein) is known to affect body weight, but its systemic context and underlying mechanisms remain unclear. Here, we found that mice lacking or overexpressing Fto in agouti-related peptide-expressing (AgRP) neurons in the hypothalamus exhibited decreased and increased body weight, respectively. FTO demethylated m6A on mRNAs for proteins associated with membrane trafficking and alternative splicing in AgRP neurons. Downstream, FTO-modulated alternative splicing of the axonal motor protein Kif1a affected its hinge region, which is relevant to the structure and function of KIF1A. Notably, Kif1a knockdown in AgRP neurons suppressed the weight gain of mice overexpressing Fto. In addition, FTO increased the trafficking and secretion of dense-core vesicles containing neuropeptides NPY and AgRP from AgRP neurons. Collectively, these results reveal a novel regulatory FTO-KIF1A axis in the brain affecting appetite-stimulating AgRP neurons and systemic energy homeostasis, via FTO regulation of the epitranscriptome of AgRP neurons.

Animals

Genome-Wide Association Study of Varenicline-Aided Smoking Cessation.

INTRODUCTION: Varenicline is an &#x3b1;4&#x3b2;2 nicotinic acetylcholine receptor partial agonist with the highest therapeutic efficacy of any pharmacological smoking cessation aid and a 12-month cessation rate of 26%. Genetic variation may be associated with varenicline response, but to date, no genome-wide association studies of varenicline response have been published. METHODS: In this study, we investigated the genetic contribution to varenicline effectiveness using two electronic health record-derived phenotypes. We defined short-term varenicline effectiveness (SVE) and long-term varenicline effectiveness (LVE) by assessing smoking status at 3 and 12 months, respectively, after initiating varenicline treatment. In Stage 1, comprising five European cohort studies, we tested genome-wide associations with SVE (1405 cases, 2074 controls) and LVE (1576 cases, 2555 controls), defining sentinel variants (the most strongly associated variant within 1&#xa0;Mb) with p-value < 5&#x2005;&#xd7;&#x2005;10-6 to follow up in Stage 2. In Stage 2, we tested association between sentinel variants and comparable smoking cessation endpoints in varenicline randomized controlled trials. We subsequently meta-analyzed Stages 1 and 2. RESULTS: No variants reached genome-wide significance in the meta-analysis. In Stage 1, 10 sentinel variants were associated with SVE and five with LVE at a suggestive significance threshold (p-value&#x2005;<&#x2005;5&#x2005;&#xd7;&#x2005;10-6); none of these sentinels were previously implicated in varenicline-aided smoking cessation or in genetic studies of smoking behavior. CONCLUSIONS: We provide initial insights into the biological underpinnings of varenicline-aided smoking cessation, through implicating genes involved in various processes, including gene expression, cilium assembly, and early-stage development. IMPLICATIONS: Leveraging electronic health records, we undertook the largest genetic study of varenicline-aided smoking cessation to date, and the only such study to test genome-wide associations. We showed distinct genetic variants associated (p-value&#x2005;<&#x2005;5&#x2005;&#xd7;&#x2005;10-6) with varenicline-aided smoking cessation which implicate diverse cellular functions, including transcriptional regulation, RNA modification, and cilium assembly. These provide insights which, if independently corroborated, will improve understanding of varenicline response. The growing availability of biobank resources with genetic and varenicline response data will provide future opportunities for larger studies using the approach we developed.

Humans

[RNA synthesis and modifications of heart nuclear proteins during thyroid hormone deficiency].

RNA synthesis, correlation of various histones and acetylation and phosphorylation of the chromatin proteins were studied in the rat heart during monthly hypothyroidism. It was shown that [3H]uridine incorporation into heart RNA decreases considerably at hypothyrosis. The alteration in relative amounts of the histone H4 subfractions, which does not depend on the method of hypothyrosis reproduction (inhibition of thyroid function by 1-methyl-2-mercaptoimidazole, thyroidectomy) was detected by the method of analytical electrophoresis in 15% polyacrylamide gels containing 3.125 M urea and 0.9 N acetic acid. Increased incorporation of [32P]phosphate into histone fraction H2b and total fraction of acidic chromatin proteins was observed in vivo. Increased incorporation of labeled acetate into the total histone fraction and reduced incorporation into acidic nuclear proteins were obtained. It was shown that the increased incorporation of acetate into the total histone fraction was due to the increased acetylation of histones H3, H2b, H4 and acid-soluble chromatin proteins characteristic of tissues with a low level of replication. It is assumed that the observed changes of nuclear proteins reflect the process of chromatin reorganization caused by a prolonged deficiency of thyroid hormones.

Acetylation

Loss of infectivity of brome mosaic virus RNA after chemical modification of the 3' or 5' terminus.

Brome mosaic virus (BMV) RNA that had both termini chemically modified by periodate oxidation and aniline-catalyzed cleavage of the terminal nucleotide had drastically reduced infectivity. BMV RNA that was first enzymatically tyrosylated to protect the 3' terminus from modification, and then modified at the 5' terminus by periodate oxidation and aniline cleavage, had a similar reduction in infectivity. Tyrosylation followed by acetylation modifies only the 3' terminus. Nevertheless, acetylated tyrosyl-BMV RNA was less than one-fourth as infectious as a control sample subjected to procedures that differed only by the presence of tyrosinol (which prevents aminoacylation and subsequent acetylation). For each modified form of viral RNA, care was taken to test the infectivity of appropriate control samples. The integrity of the modified RNAs was examined by gel electrophoresis and by biological translation and aminoacylation assays. We conclude that, in different ways, both the 5'- and 3'-terminal structures of BMV RNA play important roles during infection of the host.

Base Sequence

A comparison of the 16S ribosomal RNAs from mesophilic and thermophilic bacilli: some modifications in the Sanger method for RNA sequencing.

Two modifications in the Sanger two dimensional electrophoretic procedure for RNA analysis are reported. One increases resolution on the primary fingerprint to the point that digests of large RNAs, of the size 1500-3000 nucleotides yield well resolved fingerprint patterns. The other is a novel endonucleolytic procedure that proves useful in determining sequences of the large oligonucleotides produced by T1 ribonuclease. These modifications have been used in determining the catalogs of oligomers produced by T1 ribonuclease digestion of 16S rRNAs from three related organisms, Bacillus subtilis, B.pumilus and B.stearothermophilus. The possible effects of adaptation to a thermophilic niche on ribosomal RNA primary structure and the phylogenetic relatedness of the two mesophilic Bacilli are discussed.

Animals

Quantitative analysis of tRNA abundance and modifications by nanopore RNA sequencing.

Transfer RNAs (tRNAs) play a central role in protein translation. Studying them has been difficult in part because a simple method to simultaneously quantify their abundance and chemical modifications is lacking. Here we introduce Nano-tRNAseq, a nanopore-based approach to sequence native tRNA populations that provides quantitative estimates of both tRNA abundances and modification dynamics in a single experiment. We show that default nanopore sequencing settings discard the vast majority of tRNA reads, leading to poor sequencing yields and biased representations of tRNA abundances based on their transcript length. Re-processing of raw nanopore current intensity signals leads to a 12-fold increase in the number of recovered tRNA reads and enables recapitulation of accurate tRNA abundances. We then apply Nano-tRNAseq to Saccharomyces cerevisiae tRNA populations, revealing crosstalks and interdependencies between different tRNA modification types within the same molecule and changes in tRNA populations in response to oxidative stress.

RNA

Mapping of RNA by a modification of the Berk-Sharp procedure: the 5' termini of 15 S beta-globin mRNA precursor and mature 10 s beta-globin mRNA have identical map coordinates.

We have used a modification of the Berk-Sharp technique to determine that the 5' termini of the mouse 15 S beta-globin precursor and the mature mRNA have identical map coordinates. The modification involves the use of 5' (or 3') terminally labeled probes; it allows the detection of the precursor in the presence of excess mature mRNA.

Animals

A study of the thermal unfolding of Escherichia coli phenylalanine transfer RNA by chemical modification at elevated temperatures.

Escherichia coli tRNAPhe was modified by 3 M sodium bisulphite pH 6.0 for 24 h in the temperature range 25 degrees C (x 5 degrees C) to 55 degrees C and in the absence of added magnesium ions. The sites and extents of conversion of cytidines to uridine occurring at each temperature were determined by fingerprinting. The new sites of cytidine modification found at higher reaction temperatures were assumed to arise from breakage of secondary and tertiary structure hydrogen bonds involving cytidine residues. From these data, we conclude that hydrogen bonds within the 'complex core' of the tRNA (including the base pairs G-10 . C-25, C-11 . G-24 and C-13 . G-21 within the dihydrouridine stem and the tertiary structure base pair G-15 . C-48 melt at a lower temperature than the tertiary structure hydrogen bonds between G-19 in the dihydrouridine loop and C-56 in the TpsiC loop.

Base Sequence

Seasonal and circadian modifications in the RNA concentration in rat adrenals after swimming effort.

Variation of the adrenal RNA as a reaction to standard physical effort--30 min. of swimming daily for 5 successive days-was studied on adult male white Wistar rats in relation to the season and the hour at which the physical effort was made. The relationship between the seasonal variation and the adrenal adaptation response to swimming was followed up in the interval between March 1972 and December 1974; the circadian variation was examined at 0600, 1200, 1800 and 0000. 1. The circannual differentiation in the response to effort is expressed in the increase of the adrenal RNA concentration, statistically non-significant in spring, maximum in summer and statistically significant in autumn; in winter, the RNA concentration, by its significant decrease as against the controls, expresses an inversion of the adrenal response to effort. 2. Within a 24-hour period the increase in the adrenal RNA concentration under effort is maximum at 1800 and generally higher at night. The fundamental chronobiologic structure of the species seems to interfere significantly the adrenal adaptation to physical effort.

Adrenal Glands

Marked for Success: How RNA m6A Methylation Fine-Tunes Gut Epithelial Function.

Post-transcriptional gene regulation-particularly through RNA modifications-plays an essential but understudied role in development, homeostasis, and regeneration of rapidly changing tissues like the mammalian intestinal epithelium. RNA modifications such as N6-methyladenosine (m&#x2076;A) represent a burgeoning area of research in posttranscriptional regulation, with m&#x2076;A being the most abundant modification found in approximately 25% of all mRNA transcripts. Multiple groups have begun to report m&#x2076;A and associated regulation of mRNA fate as critical to key process in the intestinal epithelium. In this review, we synthesize key findings to date into the following 3 categories: m&#x2076;A changes in response to the homeostatic luminal environment, m&#x2076;A as a mediator of stemness in the crypt, and m&#x2076;A as a tool for reacting to inflammation and injury. Over the course of this review, we will demonstrate how m&#x2076;A is uniquely positioned to regulate homeostasis and disease states in the challenging and dynamic environment of the intestinal epithelium.

Humans