Long non-protein-coding RNAs (lncRNAs) are proposed to be the largest transcript class in the mouse and human transcriptomes. Two important questions are whether all lncRNAs are functional and how they could exert a function. Several lncRNAs have been shown to function through their product, but this is not the only possible mode of action. In this review we focus on a role for the process of lncRNA transcription, independent of the lncRNA product, in regulating protein-coding-gene activity in cis. We discuss examples where lncRNA transcription leads to gene silencing or activation, and describe strategies to determine if the lncRNA product or its transcription causes the regulatory effect.

BackgroundLong non-coding RNAs (lncRNAs) are increasingly implicated as gene regulators and may ultimately be more numerous than protein-coding genes in the human genome. Despite large numbers of reported lncRNAs, reference annotations are likely incomplete due to their lower and tighter tissue-specific expression compared to mRNAs. An unexplored factor potentially confounding lncRNA identification is inter-individual expression variability. Here, we characterize lncRNA natural expression variability in human primary granulocytes.ResultsWe annotate granulocyte lncRNAs and mRNAs in RNA-seq data from 10 healthy individuals, identifying multiple lncRNAs absent from reference annotations, and use this to investigate three known features (higher tissue-specificity, lower expression, and reduced splicing efficiency) of lncRNAs relative to mRNAs. Expression variability was examined in seven individuals sampled three times at 1- or more than 1-month intervals. We show that lncRNAs display significantly more inter-individual expression variability compared to mRNAs. We confirm this finding in two independent human datasets by analyzing multiple tissues from the GTEx project and lymphoblastoid cell lines from the GEUVADIS project. Using the latter dataset we also show that including more human donors into the transcriptome annotation pipeline allows identification of an increasing number of lncRNAs, but minimally affects mRNA gene number.ConclusionsA comprehensive annotation of lncRNAs is known to require an approach that is sensitive to low and tight tissue-specific expression. Here we show that increased inter-individual expression variability is an additional general lncRNA feature to consider when creating a comprehensive annotation of human lncRNAs or proposing their use as prognostic or disease markers.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-016-0873-8) contains supplementary material, which is available to authorized users.

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Efficient repair of DNA lesions is essential for faithful transmission of genetic information between somatic cells and for genome integrity across generations. Plants have multiple, partially redundant and overlapping DNA repair pathways, probably due to the less constricted germline and the inevitable exposure to light including higher energy wavelengths. Many proteins involved in DNA repair and their mode of actions are well described. In contrast, a role for DNA damage-associated RNA components, evident from many other organisms, is less well understood. Here, we have challenged young Arabidopsis thaliana plants with two different types of genotoxic stress and performed de novo assembly and transcriptome analysis. We identified three long non-coding RNAs (lncRNAs) that are lowly or not expressed under regular conditions but up-regulated or induced by DNA damage. We generated CRISPR/Cas deletion mutants and found that the absence of the lncRNAs impairs the recovery capacity of the plants from genotoxic stress. The genetic loci are highly conserved among world-wide distributed Arabidopsis accessions and within related species in the Brassicaceae group. Together, these results suggest that the lncRNAs have a conserved function in connection with DNA damage and provide a basis for a mechanistic analysis of their role.

Background Long non-coding RNAs (lncRNAs) are under-studied and under-annotated in plants. In mammals, lncRNA loci are nearly as ubiquitous as protein-coding genes, and their expression has been shown to be highly variable between individuals of the same species. Using A. thaliana as a model, we aimed to understand the true scope of lncRNA transcription across plants from different regions and study its natural expression variability. Results Using RNA-seq data spanning hundreds of natural lines and several developmental stages to create a more comprehensive annotation of lncRNAs, we found over 10,000 new loci - three times as many as in the current public annotation. While lncRNA loci are ubiquitous in the genome, most appear to be actively silenced and their expression and repressive chromatin levels are extremely variable between natural lines. This was particularly common for intergenic lncRNAs, where pieces of transposable elements (TEs) present in 50% of the loci are associated with increased silencing and variation, and such lincRNAs tend to be targeted by TE silencing machinery. Conclusion lncRNAs are ubiquitous in the A. thaliana genome but largely silenced, and their expression is highly variable between different lines. This high expression variability is largely caused by high epigenetic variability of non-coding loci, especially those containing pieces of transposable elements. We create the most comprehensive A. thaliana lncRNA annotation to date and improve our understanding of plant lncRNA biology.

Many thousand long non-coding (lnc) RNAs are mapped in the human genome. Time consuming studies using reverse genetic approaches by post-transcriptional knock-down or genetic modification of the locus demonstrated diverse biological functions for a few of these transcripts. The Human Gene Trap Mutant Collection in haploid KBM7 cells is a ready-to-use tool for studying protein-coding gene function. As lncRNAs show remarkable differences in RNA biology compared to protein-coding genes, it is unclear if this gene trap collection is useful for functional analysis of lncRNAs. Here we use the uncharacterized LOC100288798 lncRNA as a model to answer this question. Using public RNA-seq data we show that LOC100288798 is ubiquitously expressed, but inefficiently spliced. The minor spliced LOC100288798 isoforms are exported to the cytoplasm, whereas the major unspliced isoform is nuclear localized. This shows that LOC100288798 RNA biology differs markedly from typical mRNAs. De novo assembly from RNA-seq data suggests that LOC100288798 extends 289kb beyond its annotated 3' end and overlaps the downstream SLC38A4 gene. Three cell lines with independent gene trap insertions in LOC100288798 were available from the KBM7 gene trap collection. RT-qPCR and RNA-seq confirmed successful lncRNA truncation and its extended length. Expression analysis from RNA-seq data shows significant deregulation of 41 protein-coding genes upon LOC100288798 truncation. Our data shows that gene trap collections in human haploid cell lines are useful tools to study lncRNAs, and identifies the previously uncharacterized LOC100288798 as a potential gene regulator.

Efficient repair of DNA lesions is essential for faithful transmission of genetic information between somatic cells and for genome integrity across generations. Plants have multiple, partially redundant and overlapping DNA repair pathways, probably due to the less constricted germline and the inevitable exposure to light including higher energy wavelengths. Many proteins involved in DNA repair and their mode of actions are well described. In contrast, a role for DNA damage-associated RNA components, evident from many other organisms, is less well understood. Here, we have challenged young Arabidopsis thaliana plants with two different types of genotoxic stress and performed de novo assembly and transcriptome analysis. We identified three long non-coding RNAs (lncRNAs) that are lowly or not expressed under regular conditions but up-regulated or induced by DNA damage. To understand their potential role in DNA repair, we generated CRISPR/Cas deletion mutants and found that the absence of the lncRNAs impairs the recovery capacity of the plants from genotoxic stress. The genetic loci are highly conserved among world-wide distributed Arabidopsis accessions and within related species in the Brassicaceae group. Together, these results suggest that the lncRNAs have a conserved function in connection with DNA damage and provide a basis for a mechanistic analysis of their role.

Increasingly autonomous machines are entering our everyday lives and it is important that they do not make it worse. Apart from safety, the development of artificial morality is extensively occupying philosophers and engineers. Importantly, the only kind of morality we have known is our own. In this paper, I overview the biological and evolutionary basis of human morality and the main approaches to artificial morality. I then discuss important aspects of natural morality that should be of crucial consideration for the field of artificial morality if we want to make future human-robot societies sustainable and flourishing.