scholarly journals Zebrafish transposable elements show extensive diversification in age, genomic distribution, and developmental expression

2022 ◽  
pp. gr.275655.121
Author(s):  
Ni-Chen Chang ◽  
Quirze Rovira ◽  
Jonathan N Wells ◽  
Cedric Feschotte ◽  
Juan M Vaquerizas
Keyword(s):  
Transposable Elements ◽  
Single Cell ◽  
Expression Patterns ◽  
Developmental Expression ◽  
Gene Promoters ◽  
Vertebrate Development ◽  
Genomic Distribution ◽  
Dna Transposons ◽  
Wide Range ◽  
The Impact

There is considerable interest in understanding the effect of transposable elements (TEs) on embryonic development. Studies in humans and mice are limited by the difficulty of working with mammalian embryos, and by the relative scarcity of active TEs in these organisms. Zebrafish is an outstanding model for the study of vertebrate development and over half of its genome consists of diverse TEs. However, zebrafish TEs remain poorly characterized. Here we describe the demography and genomic distribution of zebrafish TEs and their expression throughout embryogenesis using bulk and single-cell RNA sequencing data. These results reveal a highly dynamic genomic ecosystem comprising nearly 2,000 distinct TE families, which vary in copy number by four orders of magnitude and span a wide range of ages. Longer retroelements tend to be retained in intergenic regions, whilst short interspersed nuclear elements (SINEs) and DNA transposons are more frequently found nearby or within genes. Locus-specific mapping of TE expression reveals extensive TE transcription during development. While two thirds of TE transcripts are likely driven by nearby gene promoters, we still observe stage and tissue-specific expression patterns in self-regulated TEs. Long terminal repeat (LTR) retroelements are most transcriptionally active immediately following zygotic genome activation, whereas DNA transposons are enriched amongst transcripts expressed in later stages of development. Single-cell analysis reveals several endogenous retroviruses expressed in specific somatic cell lineages. Overall, our study provides a valuable resource for using zebrafish as a model to study the impact of TEs on vertebrate development.

scholarly journals A genomic portrait of zebrafish transposable elements and their spatiotemporal embryonic expression

2021 ◽  
Author(s):  
Ni-Chen Chang ◽  
Quirze Rovira ◽  
Jonathan N Wells ◽  
Cédric Feschotte ◽  
Juan M Vaquerizas
Keyword(s):  
Transposable Elements ◽  
Single Cell ◽  
Expression Patterns ◽  
Endogenous Retroviruses ◽  
Gene Promoters ◽  
Vertebrate Development ◽  
Sequencing Data ◽  
Dna Transposons ◽  
Wide Range ◽  
The Impact

There is considerable interest in understanding the effect of transposable elements (TEs) on embryonic development. Studies in humans and mice are limited by the difficulty of working with mammalian embryos, and by the relative scarcity of active TEs in these organisms. Zebrafish is an outstanding model for the study of vertebrate development and over half of its genome consists of diverse TEs. However, zebrafish TEs remain poorly characterized. Here we describe the demography and genomic distribution of zebrafish TEs and their expression throughout embryogenesis using bulk and single-cell RNA sequencing data. These results reveal a highly dynamic genomic ecosystem comprising nearly 2,000 distinct TE families, which vary in copy number by four orders of magnitude and span a wide range of ages. Longer retroelements tend to be retained in intergenic regions, whilst short interspersed nuclear elements (SINEs) and DNA transposons are more frequently found nearby or within genes. Locus-specific mapping of TE expression reveals extensive TE transcription during development. While two thirds of TE transcripts are likely driven by nearby gene promoters, we still observe stage and tissue-specific expression patterns in self-regulated TEs. Long terminal repeat (LTR) retroelements are most transcriptionally active immediately following zygotic genome activation, whereas DNA transposons are enriched amongst transcripts expressed in later stages of development. Single-cell analysis reveals several endogenous retroviruses expressed in specific somatic cell lineages. Overall, our study provides an important resource for using zebrafish as a model to study the impact of TEs on vertebrate development.

scholarly journals Clustering Single-Cell RNA-Seq Data with Regularized Gaussian Graphical Model

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 311
Author(s):  
Zhenqiu Liu
Keyword(s):  
Single Cell ◽  
Free Parameter ◽  
Graphical Model ◽  
Expression Patterns ◽  
Information Criterion ◽  
Log P ◽  
Rna Seq ◽  
Clustering Methods ◽  
Wide Range ◽  
Free Parameters

Single-cell RNA-seq (scRNA-seq) is a powerful tool to measure the expression patterns of individual cells and discover heterogeneity and functional diversity among cell populations. Due to variability, it is challenging to analyze such data efficiently. Many clustering methods have been developed using at least one free parameter. Different choices for free parameters may lead to substantially different visualizations and clusters. Tuning free parameters is also time consuming. Thus there is need for a simple, robust, and efficient clustering method. In this paper, we propose a new regularized Gaussian graphical clustering (RGGC) method for scRNA-seq data. RGGC is based on high-order (partial) correlations and subspace learning, and is robust over a wide-range of a regularized parameter λ. Therefore, we can simply set λ=2 or λ=log(p) for AIC (Akaike information criterion) or BIC (Bayesian information criterion) without cross-validation. Cell subpopulations are discovered by the Louvain community detection algorithm that determines the number of clusters automatically. There is no free parameter to be tuned with RGGC. When evaluated with simulated and benchmark scRNA-seq data sets against widely used methods, RGGC is computationally efficient and one of the top performers. It can detect inter-sample cell heterogeneity, when applied to glioblastoma scRNA-seq data.

The zebrafish klf gene family

Blood ◽  
2001 ◽  
Vol 98 (6) ◽  
pp. 1792-1801 ◽  
Author(s):  
Andrew C. Oates ◽  
Stephen J. Pratt ◽  
Brenda Vail ◽  
Yi-lin Yan ◽  
Robert K. Ho ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Gene Family ◽  
Danio Rerio ◽  
Expression Patterns ◽  
Regulatory Proteins ◽  
Developmental Expression ◽  
Vertebrate Development ◽  
Functional Conservation ◽  
Transcriptional Regulatory ◽  
High Degree

Abstract The Krüppel-like factor(KLF) family of genes encodes transcriptional regulatory proteins that play roles in differentiation of a diverse set of cells in mammals. For instance, the founding memberKLF1 (also known as EKLF) is required for normal globin production in mammals. Five new KLF genes have been isolated from the zebrafish, Danio rerio, and the structure of their products, their genetic map positions, and their expression during development of the zebrafish have been characterized. Three genes closely related to mammalian KLF2 andKLF4 were found, as was an ortholog of mammalianKLF12. A fifth gene, apparently missing from the genome of mammals and closely related to KLF1 and KLF2,was also identified. Analysis demonstrated the existence of novel conserved domains in the N-termini of these proteins. Developmental expression patterns suggest potential roles for these zebrafish genes in diverse processes, including hematopoiesis, blood vessel function, and fin and epidermal development. The studies imply a high degree of functional conservation of the zebrafish genes with their mammalian homologs. These findings further the understanding of theKLF genes in vertebrate development and indicate an ancient role in hematopoiesis for the Krüppel-like factorgene family.

scholarly journals Comprehensive In Silico Analysis and Transcriptional Profiles Highlight the Importance of Mitochondrial Dicarboxylate Carriers (DICs) on Hypoxia Response in Both Arabidopsis thaliana and Eucalyptus grandis

Plants ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 181
Author(s):  
Pedro Barreto ◽  
Mariana L. C. Arcuri ◽  
Rômulo Pedro Macêdo Lima ◽  
Celso Luis Marino ◽  
Ivan G. Maia
Keyword(s):  
In Silico ◽  
Seedling Survival ◽  
Expression Patterns ◽  
Eucalyptus Grandis ◽  
In Silico Analysis ◽  
Developmental Expression ◽  
Hypoxia Response ◽  
Submergence Stress ◽  
Wide Range ◽  
Silico Analysis

Plant dicarboxylate carriers (DICs) transport a wide range of dicarboxylates across the mitochondrial inner membrane. The Arabidopsis thalianaDIC family is composed of three genes (AtDIC1, 2 and 3), whereas two genes (EgDIC1 and EgDIC2) have been retrieved in Eucalyptus grandis. Here, by combining in silico and in planta analyses, we provide evidence that DICs are partially redundant, important in plant adaptation to environmental stresses and part of a low-oxygen response in both species. AtDIC1 and AtDIC2 are present in most plant species and have very similar gene structure, developmental expression patterns and absolute expression across natural Arabidopsis accessions. In contrast, AtDIC3 seems to be an early genome acquisition found in Brassicaceae and shows relatively low (or no) expression across these accessions. In silico analysis revealed that both AtDICs and EgDICs are highly responsive to stresses, especially to cold and submergence, while their promoters are enriched for stress-responsive transcription factors binding sites. The expression of AtDIC1 and AtDIC2 is highly correlated across natural accessions and in response to stresses, while no correlation was found for AtDIC3. Gene ontology enrichment analysis suggests a role for AtDIC1 and AtDIC2 in response to hypoxia, and for AtDIC3 in phosphate starvation. Accordingly, the investigated genes are induced by submergence stress in A. thaliana and E. grandis while AtDIC2 overexpression improved seedling survival to submergence. Interestingly, the induction of AtDIC1 and AtDIC2 is abrogated in the erfVII mutant that is devoid of plant oxygen sensing, suggesting that these genes are part of a conserved hypoxia response in Arabidopsis.

scholarly journals scDD: A statistical approach for identifying differential distributions in single-cell RNA-seq experiments

2015 ◽  
Author(s):  
Keegan D. Korthauer ◽  
Li-Fang Chu ◽  
Michael A. Newton ◽  
Yuan Li ◽  
James Thomson ◽  
...  
Keyword(s):  
Single Cell ◽  
Expression Patterns ◽  
Mean Shift ◽  
R Package ◽  
Study Data ◽  
Cellular Heterogeneity ◽  
Modeling Framework ◽  
Wide Range ◽  
Higher Power ◽  
Novel Method

AbstractThe ability to quantify cellular heterogeneity is a major advantage of single-cell technologies. Although understanding such heterogeneity is of primary interest in a number of studies, for convenience, statistical methods often treat cellular heterogeneity as a nuisance factor. We present a novel method to characterize differences in expression in the presence of distinct expression states within and among biological conditions. Using simulated and case study data, we demonstrate that the modeling framework is able to detect differential expression patterns of interest under a wide range of settings. Compared to existing approaches, scDD has higher power to detect subtle differences in gene expression distributions that are more complex than a mean shift, and is able to characterize those differences. The freely available R package scDD implements the approach.

scholarly journals Giotto, a toolbox for integrative analysis and visualization of spatial expression data

2019 ◽  
Author(s):  
Ruben Dries ◽  
Qian Zhu ◽  
Rui Dong ◽  
Chee-Huat Linus Eng ◽  
Huipeng Li ◽  
...  
Keyword(s):  
Gene Expression ◽  
Data Analysis ◽  
Single Cell ◽  
Rapid Development ◽  
Expression Patterns ◽  
Imaging Features ◽  
Expression Data ◽  
General Applicability ◽  
Proteomic Data ◽  
Wide Range

AbstractThe rapid development of novel spatial transcriptomic and proteomic technologies has provided new opportunities to investigate the interactions between cells and their native microenvironment. However, effective use of such technologies requires the development of innovative computational tools that are easily accessible and intuitive to use. Here we present Giotto, a comprehensive, flexible, robust, and open-source toolbox for spatial transcriptomic and proteomic data analysis and visualization. The data analysis module provides end-to-end analysis by implementing a wide range of algorithms for characterizing cell-type distribution, spatially coherent gene expression patterns, and interactions between each cell and its surrounding neighbors. Furthermore, Giotto can also be used in conjunction with external single-cell RNAseq data to infer the spatial enrichment of cell types from data that do not have single-cell resolution. The data visualization module allows users to interactively visualize the gene expression data, analysis outputs, and additional imaging features, thereby providing a user-friendly workspace to explore multiple modalities of information for biological investigation. These two modules can be used iteratively for refined analysis and hypothesis development. We applied Giotto to a wide range of public datasets encompassing diverse technologies and platforms, thereby demonstrating its general applicability for spatial transcriptomic and proteomic data analysis and visualization.

scholarly journals Dynamics of transposable elements in recently diverged fungal pathogens: lineage-specific transposable element content and efficiency of genome defenses

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Cécile Lorrain ◽  
Alice Feurtey ◽  
Mareike Möller ◽  
Janine Haueisen ◽  
Eva Stukenbrock
Keyword(s):  
Transposable Elements ◽  
Related Species ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
De Novo ◽  
Zymoseptoria Tritici ◽  
Closely Related Species ◽  
Fungal Plant Pathogens ◽  
Wide Range ◽  
The Impact

Abstract Transposable elements (TEs) impact genome plasticity, architecture, and evolution in fungal plant pathogens. The wide range of TE content observed in fungal genomes reflects diverse efficacy of host-genome defense mechanisms that can counter-balance TE expansion and spread. Closely related species can harbor drastically different TE repertoires. The evolution of fungal effectors, which are crucial determinants of pathogenicity, has been linked to the activity of TEs in pathogen genomes. Here, we describe how TEs have shaped genome evolution of the fungal wheat pathogen Zymoseptoria tritici and four closely related species. We compared de novo TE annotations and repeat-induced point mutation signatures in 26 genomes from the Zymoseptoria species-complex. Then, we assessed the relative insertion ages of TEs using a comparative genomics approach. Finally, we explored the impact of TE insertions on genome architecture and plasticity. The 26 genomes of Zymoseptoria species reflect different TE dynamics with a majority of recent insertions. TEs associate with accessory genome compartments, with chromosomal rearrangements, with gene presence/absence variation, and with effectors in all Zymoseptoria species. We find that the extent of RIP-like signatures varies among Z. tritici genomes compared to genomes of the sister species. The detection of a reduction of RIP-like signatures and TE recent insertions in Z. tritici reflects ongoing but still moderate TE mobility.

scholarly journals Jump around: transposons in and out of the laboratory

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 135
Author(s):  
Anuj Kumar
Keyword(s):  
Transposable Elements ◽  
Dna Sequences ◽  
Major Constituent ◽  
Mobile Dna ◽  
Mutagenic Potential ◽  
Complex Interactions ◽  
Wide Range ◽  
Transposon Insertions ◽  
The Impact

Since Barbara McClintock’s groundbreaking discovery of mobile DNA sequences some 70 years ago, transposable elements have come to be recognized as important mutagenic agents impacting genome composition, genome evolution, and human health. Transposable elements are a major constituent of prokaryotic and eukaryotic genomes, and the transposition mechanisms enabling transposon proliferation over evolutionary time remain engaging topics for study, suggesting complex interactions with the host, both antagonistic and mutualistic. The impact of transposition is profound, as over 100 human heritable diseases have been attributed to transposon insertions. Transposition can be highly mutagenic, perturbing genome integrity and gene expression in a wide range of organisms. This mutagenic potential has been exploited in the laboratory, where transposons have long been utilized for phenotypic screening and the generation of defined mutant libraries. More recently, barcoding applications and methods for RNA-directed transposition are being used towards new phenotypic screens and studies relevant for gene therapy. Thus, transposable elements are significant in affecting biology both in vivo and in the laboratory, and this review will survey advances in understanding the biological role of transposons and relevant laboratory applications of these powerful molecular tools.

Maize unstable factor for orange1 is essential for endosperm development and carbohydrate accumulation

2021 ◽  
Author(s):  
Debamalya Chatterjee ◽  
Kameron Wittmeyer ◽  
Tzuu-fen Lee ◽  
Jin Cui ◽  
Neela H Yennawar ◽  
...  
Keyword(s):  
Expression Patterns ◽  
Ectopic Expression ◽  
Cell Types ◽  
Endosperm Development ◽  
Adjacent Cell ◽  
Specific Gene ◽  
Loss Of Function ◽  
Wall Ingrowth ◽  
Wide Range ◽  
The Impact

Abstract Maize (Zea mays L.) Ufo1-1 is a spontaneous dominant mutation of the unstable factor for orange1 (ufo1). We recently cloned ufo1, which is a Poaceae specific gene expressed solely during seed development in maize. Here we have characterized Ufo1-1 and a loss-of-function Ds insertion allele (ufo1-Dsg) to decipher the role of ufo1 in maize. We found that both ufo1 mutant alleles impact sugars and hormones, and have defects in the basal endosperm transfer layer (BETL) and adjacent cell types. The Ufo1-1 BETL had reduced cell elongation and cell wall ingrowth, resulting in cuboidal shaped transfer cells. In contrast, the ufo1-Dsg BETL cells showed a reduced overall size with abnormal wall ingrowth. Expression analysis identified the impact of ufo1 on several genes essential for BETL development. The overexpression of Ufo1-1 in various tissues leads to ectopic phenotypes, including abnormal cell organization and stomata subsidiary cell defects. Interestingly, pericarp and leaf transcriptomes also showed that as compared to wild type, Ufo1-1 had ectopic expression of endosperm development-specific genes. This study shows that Ufo1-1 impacts the expression patterns of a wide range of genes involved in various developmental processes.

scholarly journals Widespread correlation of KRAB zinc finger protein binding with brain-developmental gene expression patterns

2020 ◽  
Vol 375 (1795) ◽  
pp. 20190333 ◽  
Author(s):  
Grace Farmiloe ◽  
Gerrald A. Lodewijk ◽  
Stijn F. Robben ◽  
Elisabeth J. van Bree ◽  
Frank M. J. Jacobs
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Human Brain ◽  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Expression Patterns ◽  
Repetitive Sequences ◽  
Brain Atlas ◽  
Gene Promoters ◽  
The Impact

The large family of KRAB zinc finger (KZNF) genes are transcription factors implicated in recognizing and repressing repetitive sequences such as transposable elements (TEs) in our genome. Through successive waves of retrotransposition-mediated insertions, various classes of TEs have invaded mammalian genomes at multiple timepoints throughout evolution. Even though most of the TE classes in our genome lost the capability to retrotranspose millions of years ago, it remains elusive why the KZNFs that evolved to repress them are still retained in our genome. One hypothesis is that KZNFs become repurposed for other regulatory roles. Here, we find evidence that evolutionary changes in KZNFs provide them not only with the ability to repress TEs, but also to bind to gene promoters independent of TEs. Using KZNF binding site data in conjunction with gene expression values from the Allen Brain Atlas, we show that KZNFs have the ability to regulate gene expression in the human brain in a region-specific manner. Our analysis shows that the expression of KZNFs shows correlation with the expression of their target genes, suggesting that KZNFs have a direct influence on gene expression in the developing human brain. The extent of this regulation and the impact it has on primate brain evolution are still to be determined, but our results imply that KZNFs have become widely integrated into neuronal gene regulatory networks. Our analysis predicts that gene expression networks have been repeatedly innovated throughout primate evolution, continuously gaining new layers of gene regulation mediated by both TEs and KZNFs in our genome. This article is part of a discussion meeting issue ‘Crossroads between transposons and gene regulation’.

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