Regulation of transposable elements: Interplay between TE-encoded regulatory sequences and host-specifictrans-acting factors inDrosophila melanogaster

2017 ◽  
Vol 26 (19) ◽  
pp. 5149-5159 ◽  
Author(s):  
Ana Marija Jakšić ◽  
Robert Kofler ◽  
Christian Schlötterer
Keyword(s):  
Transposable Elements ◽  
Regulatory Sequences

scholarly journals Role of Transposable Elements in Gene Regulation in the Human Genome

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 118
Author(s):  
Arsala Ali ◽  
Kyudong Han ◽  
Ping Liang
Keyword(s):  
Gene Regulation ◽  
Transposable Elements ◽  
Regulatory Sequences ◽  
Rna Sequences ◽  
Expression Of Genes ◽  
Wide Range ◽  
Lineage Specificity ◽  
Regulatory Rnas ◽  
Potential Factors ◽  
Interspersed Repeats

Transposable elements (TEs), also known as mobile elements (MEs), are interspersed repeats that constitute a major fraction of the genomes of higher organisms. As one of their important functional impacts on gene function and genome evolution, TEs participate in regulating the expression of genes nearby and even far away at transcriptional and post-transcriptional levels. There are two known principal ways by which TEs regulate the expression of genes. First, TEs provide cis-regulatory sequences in the genome with their intrinsic regulatory properties for their own expression, making them potential factors for regulating the expression of the host genes. TE-derived cis-regulatory sites are found in promoter and enhancer elements, providing binding sites for a wide range of trans-acting factors. Second, TEs encode for regulatory RNAs with their sequences showed to be present in a substantial fraction of miRNAs and long non-coding RNAs (lncRNAs), indicating the TE origin of these RNAs. Furthermore, TEs sequences were found to be critical for regulatory functions of these RNAs, including binding to the target mRNA. TEs thus provide crucial regulatory roles by being part of cis-regulatory and regulatory RNA sequences. Moreover, both TE-derived cis-regulatory sequences and TE-derived regulatory RNAs have been implicated in providing evolutionary novelty to gene regulation. These TE-derived regulatory mechanisms also tend to function in a tissue-specific fashion. In this review, we aim to comprehensively cover the studies regarding these two aspects of TE-mediated gene regulation, mainly focusing on the mechanisms, contribution of different types of TEs, differential roles among tissue types, and lineage-specificity, based on data mostly in humans.

scholarly journals “What You Need, Baby, I Got It”: Transposable Elements as Suppliers of Cis-Operating Sequences in Drosophila

Biology ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 25 ◽  
Author(s):  
Roberta Moschetti ◽  
Antonio Palazzo ◽  
Patrizio Lorusso ◽  
Luigi Viggiano ◽  
René Massimiliano Marsano
Keyword(s):  
Transposable Elements ◽  
Transcriptional Control ◽  
Environmental Changes ◽  
Model Organism ◽  
Model Organisms ◽  
Regulatory Sequences ◽  
Transcriptional Pattern ◽  
Constitutive Components ◽  
Host Genes

Transposable elements (TEs) are constitutive components of both eukaryotic and prokaryotic genomes. The role of TEs in the evolution of genes and genomes has been widely assessed over the past years in a variety of model and non-model organisms. Drosophila is undoubtedly among the most powerful model organisms used for the purpose of studying the role of transposons and their effects on the stability and evolution of genes and genomes. Besides their most intuitive role as insertional mutagens, TEs can modify the transcriptional pattern of host genes by juxtaposing new cis-regulatory sequences. A key element of TE biology is that they carry transcriptional control elements that fine-tune the transcription of their own genes, but that can also perturb the transcriptional activity of neighboring host genes. From this perspective, the transposition-mediated modulation of gene expression is an important issue for the short-term adaptation of physiological functions to the environmental changes, and for long-term evolutionary changes. Here, we review the current literature concerning the regulatory and structural elements operating in cis provided by TEs in Drosophila. Furthermore, we highlight that, besides their influence on both TEs and host genes expression, they can affect the chromatin structure and epigenetic status as well as both the chromosome’s structure and stability. It emerges that Drosophila is a good model organism to study the effect of TE-linked regulatory sequences, and it could help future studies on TE–host interactions in any complex eukaryotic genome.

scholarly journals Transposable elements as a potent source of diverse cis -regulatory sequences in mammalian genomes

2020 ◽  
Vol 375 (1795) ◽  
pp. 20190347 ◽  
Author(s):  
Vasavi Sundaram ◽  
Joanna Wysocka
Keyword(s):  
Gene Regulation ◽  
Transposable Elements ◽  
Regulatory Networks ◽  
Regulatory Elements ◽  
Regulatory Function ◽  
Specific Gene ◽  
Regulatory Sequences ◽  
Dependent Manner ◽  
Unique Contribution ◽  
Regulatory Potential

Eukaryotic gene regulation is mediated by cis -regulatory elements, which are embedded within the vast non-coding genomic space and recognized by the transcription factors in a sequence- and context-dependent manner. A large proportion of eukaryotic genomes, including at least half of the human genome, are composed of transposable elements (TEs), which in their ancestral form carried their own cis -regulatory sequences able to exploit the host trans environment to promote TE transcription and facilitate transposition. Although not all present-day TE copies have retained this regulatory function, the preexisting regulatory potential of TEs can provide a rich source of cis -regulatory innovation for the host. Here, we review recent evidence documenting diverse contributions of TE sequences to gene regulation by functioning as enhancers, promoters, silencers and boundary elements. We discuss how TE-derived enhancer sequences can rapidly facilitate changes in existing gene regulatory networks and mediate species- and cell-type-specific regulatory innovations, and we postulate a unique contribution of TEs to species-specific gene expression divergence in pluripotency and early embryogenesis. With advances in genome-wide technologies and analyses, systematic investigation of TEs' cis -regulatory potential is now possible and our understanding of the biological impact of genomic TEs is increasing. This article is part of a discussion meeting issue ‘Crossroads between transposons and gene regulation’.

scholarly journals Conservation patterns’ analysis of 18,364 candidate human-specific regulatory sequences revealed two distinct pathways of the human regulatory DNA divergence

2015 ◽  
Author(s):  
Gennadi Glinsky
Keyword(s):  
Transposable Elements ◽  
Regulatory Networks ◽  
Homo Sapiens ◽  
Functional Divergence ◽  
Regulatory Sequences ◽  
Conservation Patterns ◽  
Genomic Regulatory Networks ◽  
Species Specific ◽  
Regulatory Dna ◽  
Human Specific

Thousands of candidate human-specific regulatory sequences (HSRS) have been identified, supporting the idea that unique to human phenotypes result from human-specific alterations of genomic regulatory networks. Here, conservation patterns analysis of 18,364 regulatory DNA segments comprising candidate HSRS was carried out using the most recent releases of the reference genomes’ databases of humans and nonhuman primates (NHP) and defining the sequence conservation threshold as the minimum ratio of bases that must remap of 1.00. Present analyses identified 5,535 candidate HSRS defined by either the acceleration of mutation rates on the human lineage or the functional divergence from chimpanzee that are highly conserved in NHP and appear to evolve by the exaptation of ancestral DNA pathway. This pathway seems mechanistically distinct from the evolution of regulatory DNA driven by the species-specific expansion of transposable elements. It is proposed that phenotypic divergence of Homo sapiens is driven by the evolution of human-specific genomic regulatory networks via at least two mechanistically distinct pathways of creation of divergent sequences of regulatory DNA: i) exaptation of the highly conserved ancestral regulatory DNA segments; ii) human-specific insertions of transposable elements.

scholarly journals Role of Transposable Elements in Gene Regulation in the Human Genome

2021 ◽  
Author(s):  
Arsala Ali ◽  
Kyudong Han ◽  
Ping Liang
Keyword(s):  
Gene Regulation ◽  
Transposable Elements ◽  
Regulatory Sequences ◽  
Rna Sequences ◽  
Expression Of Genes ◽  
Wide Range ◽  
Lineage Specificity ◽  
Regulatory Rnas ◽  
Potential Factors ◽  
Interspersed Repeats

Transposable elements (TEs), also known as mobile elements (MEs), are interspersed repeats that constitute a major fraction of the genomes of higher organisms. As one of their important functional impacts on gene function and genome evolution, TEs participate in regulating the expression of genes nearby and even far away at transcriptional and post-transcriptional levels. There are two known principal ways by which TEs regulate expression of genes. First, TEs provide cis-regulatory sequences in the genome with their intrinsic regulatory properties for their own expression making them potential factors for regulating the expression of the host genes. TE-derived cis-regulatory sites are found in promoter and enhancer elements, providing binding sites for a wide range of trans-acting factors. Second, TEs encode for regulatory RNAs with their sequences showed to be present in a substantial fraction of miRNAs and long non-coding RNAs (lncRNAs), indicating the TE origin of these RNAs. Furthermore, TEs sequences were found to be critical for regulatory functions of these RNAs including binding to the target mRNA. TEs thus provide crucial regulatory roles by being part of cis-regulatory and regulatory RNA sequences. Moreover, both TE-derived cis-regulatory sequences and TE-derived regulatory RNAs, have been implicated to provide evolutionary novelty to gene regulation. These TE-derived regulatory mechanisms also tend to function in tissue-specific fashion. In this review, we aim to comprehensively cover the studies regarding these two aspects of TE-mediated gene regulation, mainly focusing on the mechanisms, contribution of different types of TEs, differential roles among tissue types, and lineage specificity, based on data mostly in humans.

scholarly journals Transposable elements mediate genetic effects altering the expression of nearby genes in colorectal cancer

2021 ◽  
Author(s):  
Nikolaos Lykoskoufis ◽  
Evarist Planet ◽  
Halit Ongen ◽  
Didier Trono ◽  
Emmanouil T Dermitzakis
Keyword(s):  
Colorectal Cancer ◽  
Transposable Elements ◽  
Genetic Effect ◽  
Regulatory Sequences ◽  
Driver Genes ◽  
Cancer Driver ◽  
Tumor Tissues ◽  
Interspersed Repeats ◽  
Methylation Patterns ◽  
The Impact

Abstract Transposable elements (TEs) are interspersed repeats that contribute to more than half of the human genome, and TE-embedded regulatory sequences are increasingly recognized as major components of the human regulome. Perturbations of this system can contribute to tumorigenesis, but the impact of TEs on gene expression in cancer cells remains to be fully assessed. Here, we analyzed 275 normal colon and 276 colorectal cancer (CRC) samples from the SYSCOL colorectal cancer cohort and discovered 10,111 and 5,152 TE expression quantitative trait loci (eQTLs) in normal and tumor tissues, respectively. Amongst the latter, 376 were exclusive to CRC, likely driven by changes in methylation patterns. We identified that transcription factors are more enriched in tumor-specific TE-eQTLs than shared TE-eQTLs, indicating that TEs are more specifically regulated in tumor than normal. Using Bayesian Networks to assess the causal relationship between eQTL variants, TEs and genes, we identified that 1,758 TEs are mediators of genetic effect, altering the expression of 1,626 nearby genes significantly more in tumor compared to normal, of which 51 are cancer driver genes. We show that tumor-specific TE-eQTLs trigger the driver capability of TEs subsequently impacting expression of nearby genes. Collectively, our results highlight a global profile of a new class of cancer drivers, thereby enhancing our understanding of tumorigenesis and providing potential new candidate mechanisms for therapeutic target development.

scholarly journals DNA methylation in transposable elements disrupts the connection between three-dimensional chromatin organization and gene expression upon rice genome duplication.

2021 ◽  
Author(s):  
Zhenfei Sun ◽  
Yunlong Wang ◽  
Zhaojian Song ◽  
Hui Zhang ◽  
Min Ma ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transposable Elements ◽  
Genome Duplication ◽  
Rice Genome ◽  
Three Dimensional ◽  
Plant Evolution ◽  
Chromatin Organization ◽  
Regulatory Sequences ◽  
Chromosome Conformation ◽  
Significant Difference

Polyploidy serves as a major force in plant evolution and domestication of cultivated crops. However, the relationship and underlying mechanism between three-dimensional (3D) chromatin organization and gene expression upon rice genome duplication is largely unknown. Here we compared the 3D chromatin structures between diploid (2C) and autotetraploid (4C) rice by high-throughput chromosome conformation capture analysis, and found that 4C rice presents weakened intra-chromosomal interactions compared to its 2C progenitor. Moreover, we found that changes of 3D chromatin organizations including chromatin compartments, topologically associating domain (TAD) and loops uncouple from gene expression. Moreover, DNA methylations in the regulatory sequences of genes in compartment A/B switched regions and TAD boundaries are not related to their expressions. Importantly, in contrast to that there was no significant difference of methylation levels in TEs in promoters of differentially expressed genes (DEGs) and non-DEGs between 2C and 4C rice, we found that the hypermethylated transposable elements across genes in compartment A/B switched regions and TAD boundaries suppress the expression of these genes. We propose that the rice genome doubling might modulate TE methylation which results in the disconnection between the alteration of 3D chromatin structure and gene expression.

scholarly journals Transposable elements mediate genetic effects altering the expression of nearby genes in colorectal cancer

2021 ◽  
Author(s):  
Nikolaos M. R. Lykoskoufis ◽  
Evarist Planet ◽  
Halit Ongen ◽  
Didier Trono ◽  
Emmanouil T. Dermitzakis
Keyword(s):  
Colorectal Cancer ◽  
Transposable Elements ◽  
Genetic Effect ◽  
Regulatory Sequences ◽  
Driver Genes ◽  
Cancer Driver ◽  
Tumor Tissues ◽  
Interspersed Repeats ◽  
Methylation Patterns ◽  
The Impact

ABSTRACTTransposable elements (TEs) are interspersed repeats that contribute to more than half of the human genome, and TE-embedded regulatory sequences are increasingly recognized as major components of the human regulome. Perturbations of this system can contribute to tumorigenesis, but the impact of TEs on gene expression in cancer cells remains to be fully assessed. Here, we analyzed 275 normal colon and 276 colorectal cancer (CRC) samples from the SYSCOL colorectal cancer cohort and discovered 10,111 and 5,152 TE expression quantitative trait loci (eQTLs) in normal and tumor tissues, respectively. Amongst the latter, 376 were exclusive to CRC, likely driven by changes in methylation patterns. We identified that transcription factors are more enriched in tumor-specific TE-eQTLs than shared TE-eQTLs, indicating that TEs are more specifically regulated in tumor than normal. Using Bayesian Networks to assess the causal relationship between eQTL variants, TEs and genes, we identified that 1,758 TEs are mediators of genetic effect, altering the expression of 1,626 nearby genes significantly more in tumor compared to normal, of which 51 are cancer driver genes. We show that tumor-specific TE-eQTLs trigger the driver capability of TEs subsequently impacting expression of nearby genes. Collectively, our results highlight a global profile of a new class of cancer drivers, thereby enhancing our understanding of tumorigenesis and providing potential new candidate mechanisms for therapeutic target development.

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