Fetal growth delay caused by loss of non-canonical imprinting is resolved late in pregnancy and culminates in offspring overgrowth.

Germline epigenetic programming, including genomic imprinting, substantially influences offspring development. Polycomb Repressive Complex 2 (PRC2) plays an important role in Histone 3 Lysine 27 trimethylation (H3K27me3)-dependent imprinting, loss of which leads to growth and developmental changes in mouse offspring. In this study, we show that offspring from mouse oocytes lacking the PRC2 protein Embryonic Ectoderm Development (EED) were initially developmentally delayed, characterised by low blastocyst cell counts and substantial growth delay in mid-gestation embryos. This initial developmental delay was resolved as offspring underwent accelerated fetal development and growth in late gestation resulting in offspring that were similar stage and weight to controls at birth. The accelerated development and growth in offspring from Eed-null oocytes was associated with remodelling of the placenta, which involved an increase in fetal and maternal tissue size, conspicuous expansion of the glycogen-enriched cell population, and delayed parturition. Despite placental remodelling and accelerated offspring fetal growth and development, placental efficiency, and fetal blood glucose levels were low, and the fetal blood metabolome was unchanged. Moreover, while expression of the H3K27me3-imprinted gene and amino acid transporter Slc38a4 was increased, fetal blood levels of individual amino acids were similar to controls, indicating that placental amino acid transport was not enhanced. Genome-wide analyses identified extensive transcriptional dysregulation and DNA methylation changes in affected placentas, including a range of imprinted and non-imprinted genes. Together, while deletion of Eed in growing oocytes resulted in fetal growth and developmental delay and placental hyperplasia, our data indicate a remarkable capacity for offspring fetal growth to be normalised despite inefficient placental function and the loss of H3K27me3-dependent genomic imprinting.

An unmet need for pharmacology: Treatments for radiation-induced gastrointestinal mucositis.

Gastrointestinal mucositis (GIM) continues to be a significant issue in the management of abdominal cancer radiation treatments and chemotherapy, causing significant patient discomfort and therapy interruption or even cessation. This review will first focus on radiotherapy induced GIM, providing an understanding of its clinical landscape. Subsequently, the aetiology of GIM will be reviewed, highlighting diverse contributing factors. The cellular and tissue damage and associated molecular responses in GIM will be summarised in the context of the underlying complex biological processes. Finally, available drugs and pharmaceutical therapies will be evaluated, underscoring their insufficiency, and highlighting the need for further research and innovation. This review will emphasize the urgent need for improved pharmacologic therapeutics for GIM, which is a key research priority in oncology.

Multiple horizontal transfer events of a DNA transposon into turtles, fishes, and a frog.

Horizontal transfer of transposable elements (HTT) has been reported across many species and the impact of such events on genome structure and function has been well described. However, few studies have focused on reptilian genomes, especially HTT events in Testudines (turtles). Here, as a consequence of investigating the repetitive content of Malaclemys terrapin terrapin (Diamondback turtle) we found a high similarity DNA transposon, annotated in RepBase as hAT-6_XT, shared between other turtle species, ray-finned fishes, and a frog. hAT-6_XT was notably absent in reptilian taxa closely related to turtles, such as crocodiles and birds. Successful invasion of DNA transposons into new genomes requires the conservation of specific residues in the encoded transposase, and through structural analysis, these residues were identified indicating some retention of functional transposition activity. We document six recent independent HTT events of a DNA transposon in turtles, which are known to have a low genomic evolutionary rate and ancient repeats.

Differential allelic representation (DAR) identifies candidate eQTLs and improves transcriptome analysis.

In comparisons between mutant and wild-type genotypes, transcriptome analysis can reveal the direct impacts of a mutation, together with the homeostatic responses of the biological system. Recent studies have highlighted that, when the effects of homozygosity for recessive mutations are studied in non-isogenic backgrounds, genes located proximal to the mutation on the same chromosome often appear over-represented among those genes identified as differentially expressed (DE). One hypothesis suggests that DE genes chromosomally linked to a mutation may not reflect functional responses to the mutation but, instead, result from an unequal distribution of expression quantitative trait loci (eQTLs) between sample groups of mutant or wild-type genotypes. This is problematic because eQTL expression differences are difficult to distinguish from genes that are DE due to functional responses to a mutation. Here we show that chromosomally co-located differentially expressed genes (CC-DEGs) are also observed in analyses of dominant mutations in heterozygotes. We define a method and a metric to quantify, in RNA-sequencing data, localised differential allelic representation (DAR) between those sample groups subjected to differential expression analysis. We show how the DAR metric can predict regions prone to eQTL-driven differential expression, and how it can improve functional enrichment analyses through gene exclusion or weighting-based approaches. Advantageously, this improved ability to identify probable eQTLs also reveals examples of CC-DEGs that are likely to be functionally related to a mutant phenotype. This supports a long-standing prediction that selection for advantageous linkage disequilibrium influences chromosome evolution. By comparing the genomes of zebrafish (Danio rerio) and medaka (Oryzias latipes), a teleost with a conserved ancestral karyotype, we find possible examples of chromosomal aggregation of CC-DEGs during evolution of the zebrafish lineage. Our method for DAR analysis requires only RNA-sequencing data, facilitating its application across new and existing datasets.

LncRNA DANA1 promotes drought tolerance and histone deacetylation of drought responsive genes in Arabidopsis.

Although many long noncoding RNAs have been discovered in plants, little is known about their biological function and mode of action. Here we show that the drought-induced long intergenic noncoding RNA DANA1 interacts with the L1p/L10e family member protein DANA1-INTERACTING PROTEIN 1 (DIP1) in the cell nucleus of Arabidopsis, and both DANA1 and DIP1 promote plant drought resistance. DANA1 and DIP1 increase histone deacetylase HDA9 binding to the CYP707A1 and CYP707A2 loci. DIP1 further interacts with PWWP3, a member of the PEAT complex that associates with HDA9 and has histone deacetylase activity. Mutation of DANA1 enhances CYP707A1 and CYP707A2 acetylation and expression resulting in impaired drought tolerance, in agreement with dip1 and pwwp3 mutant phenotypes. Our results demonstrate that DANA1 is a positive regulator of drought response and that DANA1 works jointly with the novel chromatin-related factor DIP1 on epigenetic reprogramming of the plant transcriptome during the response to drought.

Fake IDs? Widespread misannotation of DNA transposons as a general transcription factor.

Accurate annotation of genes and transposable elements (TEs) is vital for understanding genomes, but current annotation pipelines often misannotate TEs as genes. This study reveals how the general transcription factor II-I repeat domain-containing protein 2 (GTF2IRD2) erroneously annotated DNA transposons in non-mammalian species, as it contains a 3' fused hAT transposase domain. We also demonstrate the generality of this problem by identifying misannotated TEs as genes in other vertebrate genomes. Such misannotations can lead to errors in phylogenetic analyses and wasted time for investigators. The study proposes adding a final TE-check to gene annotation pipelines to mitigate this problem.

The long non-coding RNA DANA2 positively regulates drought tolerance by recruiting ERF84 to promote JMJ29-mediated histone demethylation.

Tens of thousands of long non-coding RNAs have been uncovered in plants, but few of them have been comprehensively studied for their biological function and molecular mechanism of their mode of action. Here, we show that the Arabidopsis long non-coding RNA DANA2 interacts with an AP2/ERF transcription factor ERF84 in the cell nucleus and then affects the transcription of JMJ29 that encodes a Jumonji C domain-containing histone H3K9 demethylase. Both RNA sequencing (RNA-seq) and genetic analyses demonstrate that DANA2 positively regulates drought stress responses through JMJ29. JMJ29 positively regulates the expression of ERF15 and GOLS2 by modulation of H3K9me2 demethylation. Accordingly, mutation of JMJ29 causes decreased ERF15 and GOLS2 expression, resulting in impaired drought tolerance, in agreement with drought-sensitive phenotypes of dana2 and erf84 mutants. Taken together, these results demonstrate that DANA2 is a positive regulator of drought response and works jointly with the transcriptional activator ERF84 to modulate JMJ29 expression in plant response to drought.

Chromosomal level genome assembly of medicinal plant Sophora flavescens.

Sophora flavescens is a medicinal plant in the genus Sophora of the Fabaceae family. The root of S. flavescens is known in China as Kushen and has a long history of wide use in multiple formulations of Traditional Chinese Medicine (TCM). In this study, we used third-generation Nanopore long-read sequencing technology combined with Hi-C scaffolding technology to de novo assemble the S. flavescens genome. We obtained a chromosomal level high-quality S. flavescens draft genome. The draft genome size is approximately 2.08 Gb, with more than 80% annotated as Transposable Elements (TEs), which have recently and rapidly proliferated. This genome size is ~5x larger than its closest sequenced relative Lupinus albus L. . We annotated 60,485 genes and examined their expression profiles in leaf, stem and root tissues, and also characterised the genes and pathways involved in the biosynthesis of major bioactive compounds, including alkaloids, flavonoids and isoflavonoids. The assembled genome highlights the very different evolutionary trajectories that have occurred in recently diverged Fabaceae, leading to smaller duplicated genomes.

Long noncoding RNA ARTA controls ABA response through MYB7 nuclear trafficking in Arabidopsis.

In eukaryotes, transcription factors are a crucial element in the regulation of gene expression, and nuclear translocation is the key to the function of transcription factors. Here, we show that the long intergenic noncoding RNA ARTA interacts with an importin ß-like protein, SAD2, through a long noncoding RNA-binding region embedded in the carboxyl terminal, and then it blocks the import of the transcription factor MYB7 into the nucleus. Abscisic acid (ABA)-induced ARTA expression can positively regulate ABI5 expression by fine-tuning MYB7 nuclear trafficking. Therefore, the mutation of arta represses ABI5 expression, resulting in desensitization to ABA, thereby reducing Arabidopsis drought tolerance. Our results demonstrate that lncRNA can hijack a nuclear trafficking receptor to modulate the nuclear import of a transcription factor during plant responses to environmental stimuli.

Detecting Horizontal Transfer of Transposons.

Transposable elements (TEs) are prevalent genomic components which can replicate as a function of mobilization in eukaryotes. Not only do they alter genome structure, they also play regulatory functions or organize chromatin structure. In addition to vertical parent-to-offspring inheritance, TEs can also horizontally "jump" between species, known as horizontal transposon transfer (HTT). This can rapidly alter the course of genome evolution. In this chapter, we provide a practical framework to detect HTT events. Our HTT detection framework is based on the use of sequence alignment to determine the divergence/conservation profiles of TE families to determine the history of expansion events. In summary, it includes (a) workflow of HTT detection from Ab initio identified TEs; (b) workflow for detecting HTT for specific, curated TEs; and (c) workflow for validating detected HTT candidates. Our framework covers two common scenarios of HTT detection in the modern omics era, and we believe it will serve as a valuable toolbox for the TE and genomics research community.

Transient Polycomb activity represses developmental genes in growing oocytes.

BACKGROUND: Non-genetic disease inheritance and offspring phenotype are substantially influenced by germline epigenetic programming, including genomic imprinting. Loss of Polycomb Repressive Complex 2 (PRC2) function in oocytes causes non-genetically inherited effects on offspring, including embryonic growth restriction followed by post-natal offspring overgrowth. While PRC2-dependent non-canonical imprinting is likely to contribute, less is known about germline epigenetic programming of non-imprinted genes during oocyte growth. In addition, de novo germline mutations in genes encoding PRC2 lead to overgrowth syndromes in human patients, but the extent to which PRC2 activity is conserved in human oocytes is poorly understood. RESULTS: In this study, we identify a discrete period of early oocyte growth during which PRC2 is expressed in mouse growing oocytes. Deletion of Eed during this window led to the de-repression of 343 genes. A high proportion of these were developmental regulators, and the vast majority were not imprinted genes. Many of the de-repressed genes were also marked by the PRC2-dependent epigenetic modification histone 3 lysine 27 trimethylation (H3K27me3) in primary-secondary mouse oocytes, at a time concurrent with PRC2 expression. In addition, we found H3K27me3 was also enriched on many of these genes by the germinal vesicle (GV) stage in human oocytes, strongly indicating that this PRC2 function is conserved in the human germline. However, while the 343 genes were de-repressed in mouse oocytes lacking EED, they were not de-repressed in pre-implantation embryos and lost H3K27me3 during pre-implantation development. This implies that H3K27me3 is a transient feature that represses a wide range of genes in oocytes. CONCLUSIONS: Together, these data indicate that EED has spatially and temporally distinct functions in the female germline to repress a wide range of developmentally important genes and that this activity is conserved in the mouse and human germlines.

Compound Kushen injection reduces severity of radiation-induced gastrointestinal mucositis in rats.

Mucositis, or damage/injury to mucous membranes of the alimentary, respiratory, or genitourinary tract, is the major side effect associated with anticancer radiotherapies. Because there is no effective treatment for mucositis at present, this is a particular issue as it limits the dose of therapy in cancer patients and significantly affects their quality of life. Gastrointestinal mucositis (GIM) occurs in patients receiving radiotherapies to treat cancers of the stomach, abdomen, and pelvis. It involves inflammation and ulceration of the gastrointestinal (GI) tract causing diarrhea, nausea and vomiting, abdominal pain, and bloating. However, there is currently no effective treatment for this debilitating condition. In this study, we investigated the potential of a type of traditional Chinese medicine (TCM), compound Kushen injection (CKI), as a treatment for GIM. It has previously been shown that major groups of chemical compounds found in CKI have anti-inflammatory effects and are capable of inhibiting the expression of pro-inflammatory cytokines. Intraperitoneal administration of CKI to Sprague Dawley (SD) rats that concurrently received abdominal irradiation over five fractions resulted in reduced severity of GIM symptoms compared to rats administered a vehicle control. Histological examination of the intestinal tissues revealed significantly less damaged villus epithelium in CKI-administered rats that had reduced numbers of apoptotic cells in the crypts. Furthermore, it was also found that CKI treatment led to decreased levels of inflammatory factors including lower levels of interleukin (IL)-1ß and IL-6 as well as myeloperoxidase (MPO)-producing cells in the intestinal mucosa. Together, our data indicate a novel effect of CKI to reduce the symptoms of radiation-induced GIM by inhibiting inflammation in the mucosa and apoptosis of epithelial cells.

Horizontal Transposon Transfer and Its Implications for the Ancestral Ecology of Hydrophiine Snakes.

Transposable elements (TEs), also known as jumping genes, are sequences able to move or copy themselves within a genome. As TEs move throughout genomes they often act as a source of genetic novelty, hence understanding TE evolution within lineages may help in understanding environmental adaptation. Studies into the TE content of lineages of mammals such as bats have uncovered horizontal transposon transfer (HTT) into these lineages, with squamates often also containing the same TEs. Despite the repeated finding of HTT into squamates, little comparative research has examined the evolution of TEs within squamates. Here we examine a diverse family of Australo-Melanesian snakes (Hydrophiinae) to examine if the previously identified, order-wide pattern of variable TE content and activity holds true on a smaller scale. Hydrophiinae diverged from Asian elapids ~30 Mya and have since rapidly diversified into six amphibious, ~60 marine and ~100 terrestrial species that fill a broad range of ecological niches. We find TE diversity and expansion differs between hydrophiines and their Asian relatives and identify multiple HTTs into Hydrophiinae, including three likely transferred into the ancestral hydrophiine from fish. These HTT events provide the first tangible evidence that Hydrophiinae reached Australia from Asia via a marine route.

Future directions for the discovery of natural product-derived immunomodulating drugs: an IUPHAR positional review.

Drug discovery from natural sources is going through a renaissance, having spent many decades in the shadow of synthetic molecule drug discovery, despite the fact that natural product-derived compounds occupy a much greater chemical space than those created through synthetic chemistry methods. With this new era comes new possibilities, not least the novel targets that have emerged in recent times and the development of state-of-the-art technologies that can be applied to drug discovery from natural sources. Although progress has been made with some immunomodulating drugs, there remains a pressing need for new agents that can be used to treat the wide variety of conditions that arise from disruption, or over-activation, of the immune system; natural products may therefore be key in filling this gap. Recognising that, at present, there is no authoritative article that details the current state-of-the-art of the immunomodulatory activity of natural products, this in-depth review has arisen from a joint effort between the International Union of Basic and Clinical Pharmacology (IUPHAR) Natural Products and Immunopharmacology Sections, with contributions from a number of world-leading researchers in the field of natural product drug discovery, to provide a "position statement" on what natural products has to offer in the search for new immunomodulatory argents. To this end, we provide a historical look at previous discoveries of naturally occurring immunomodulators, present a picture of the current status of the field and provide insight into the future opportunities and challenges for the discovery of new drugs to treat immune-related diseases.

Genome Stability Is in the Eye of the Beholder: CR1 Retrotransposon Activity Varies Significantly across Avian Diversity.

Since the sequencing of the zebra finch genome it has become clear that avian genomes, while largely stable in terms of chromosome number and gene synteny, are more dynamic at an intrachromosomal level. A multitude of intrachromosomal rearrangements and significant variation in transposable element (TE) content have been noted across the avian tree. TEs are a source of genome plasticity, because their high similarity enables chromosomal rearrangements through nonallelic homologous recombination, and they have potential for exaptation as regulatory and coding sequences. Previous studies have investigated the activity of the dominant TE in birds, chicken repeat 1 (CR1) retrotransposons, either focusing on their expansion within single orders, or comparing passerines with nonpasserines. Here, we comprehensively investigate and compare the activity of CR1 expansion across orders of birds, finding levels of CR1 activity vary significantly both between and within orders. We describe high levels of TE expansion in genera which have speciated in the last 10 Myr including kiwis, geese, and Amazon parrots; low levels of TE expansion in songbirds across their diversification, and near inactivity of TEs in the cassowary and emu for millions of years. CR1s have remained active over long periods of time across most orders of neognaths, with activity at any one time dominated by one or two families of CR1s. Our findings of higher TE activity in species-rich clades and dominant families of TEs within lineages mirror past findings in mammals and indicate that genome evolution in amniotes relies on universal TE-driven processes.

Horizontal transfer and subsequent explosive expansion of a DNA transposon in sea kraits (Laticauda).

Transposable elements (TEs) are self-replicating genetic sequences and are often described as important 'drivers of evolution'. This driving force is because TEs promote genomic novelty by enabling rearrangement, and through exaptation as coding and regulatory elements. However, most TE insertions potentially lead to neutral or harmful outcomes, therefore host genomes have evolved machinery to suppress TE expansion. Through horizontal transposon transfer (HTT) TEs can colonize new genomes, and since new hosts may not be able to regulate subsequent replication, these TEs may proliferate rapidly. Here, we describe HTT of the Harbinger-Snek DNA transposon into sea kraits (Laticauda), and its subsequent explosive expansion within Laticauda genomes. This HTT occurred following the divergence of Laticauda from terrestrial Australian elapids approximately 15-25 Mya. This has resulted in numerous insertions into introns and regulatory regions, with some insertions into exons which appear to have altered UTRs or added sequence to coding exons. Harbinger-Snek has rapidly expanded to make up 8-12% of Laticauda spp. genomes; this is the fastest known expansion of TEs in amniotes following HTT. Genomic changes caused by this rapid expansion may have contributed to adaptation to the amphibious-marine habitat.

The long noncoding RNA FRILAIR regulates strawberry fruit ripening by functioning as a noncanonical target mimic.

Long noncoding RNAs (lncRNAs) are emerging as important regulators in plant development, but few of them have been functionally characterized in fruit ripening. Here, we have identified 25,613 lncRNAs from strawberry ripening fruits based on RNA-seq data from poly(A)-depleted libraries and rRNA-depleted libraries, most of which exhibited distinct temporal expression patterns. A novel lncRNA, FRILAIR harbours the miR397 binding site that is highly conserved in diverse strawberry species. FRILAIR overexpression promoted fruit maturation in the Falandi strawberry, which was consistent with the finding from knocking down miR397, which can guide the mRNA cleavage of both FRILAIR and LAC11a (encoding a putative laccase-11-like protein). Moreover, LAC11a mRNA levels were increased in both FRILAIR overexpressing and miR397 knockdown fruits, and accelerated fruit maturation was also found in LAC11a overexpressing fruits. Overall, our study demonstrates that FRILAIR can act as a noncanonical target mimic of miR397 to modulate the expression of LAC11a in the strawberry fruit ripening process.

New Environment, New Invaders-Repeated Horizontal Transfer of LINEs to Sea Snakes.

Although numerous studies have found horizontal transposon transfer (HTT) to be widespread across metazoans, few have focused on HTT in marine ecosystems. To investigate potential recent HTTs into marine species, we searched for novel repetitive elements in sea snakes, a group of elapids which transitioned to a marine habitat at most 18 Ma. Our analysis uncovered repeated HTTs into sea snakes following their marine transition. The seven subfamilies of horizontally transferred LINE retrotransposons we identified in the olive sea snake (Aipysurus laevis) are transcribed, and hence are likely still active and expanding across the genome. A search of 600 metazoan genomes found all seven were absent from other amniotes, including terrestrial elapids, with the most similar LINEs present in fish and marine invertebrates. The one exception was a similar LINE found in sea kraits, a lineage of amphibious elapids which independently transitioned to a marine environment 25 Ma. Our finding of repeated horizontal transfer events into marine snakes greatly expands past findings that the marine environment promotes the transfer of transposons. Transposons are drivers of evolution as sources of genomic sequence and hence genomic novelty. We identified 13 candidate genes for HTT-induced adaptive change based on internal or neighboring HTT LINE insertions. One of these, ADCY4, is of particular interest as a part of the KEGG adaptation pathway "Circadian Entrainment." This provides evidence of the ecological interactions between species influencing evolution of metazoans not only through specific selection pressures, but also by contributing novel genomic material.

The tuatara genome reveals ancient features of amniote evolution.

The tuatara (Sphenodon punctatus)-the only living member of the reptilian order Rhynchocephalia (Sphenodontia), once widespread across Gondwana1,2-is an iconic species that is endemic to New Zealand2,3. A key link to the now-extinct stem reptiles (from which dinosaurs, modern reptiles, birds and mammals evolved), the tuatara provides key insights into the ancestral amniotes2,4. Here we analyse the genome of the tuatara, which-at approximately 5 Gb-is among the largest of the vertebrate genomes yet assembled. Our analyses of this genome, along with comparisons with other vertebrate genomes, reinforce the uniqueness of the tuatara. Phylogenetic analyses indicate that the tuatara lineage diverged from that of snakes and lizards around 250 million years ago. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Our genome sequence analysis identifies expansions of proteins, non-protein-coding RNA families and repeat elements, the latter of which show an amalgam of reptilian and mammalian features. The sequencing of the tuatara genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. Our study also provides important insights into both the technical challenges and the cultural obligations that are associated with genome sequencing.