scholarly journals Traces of transposable elements in genome dark matter co-opted by flowering gene regulation networks

2019 ◽  
Author(s):  
Agnès Baud ◽  
Mariène Wan ◽  
Danielle Nouaud ◽  
Nicolas Francillonne ◽  
Dominique Anxolabéhère ◽  
...  

1AbstractTransposable elements (TEs) are mobile, repetitive DNA sequences that make the largest contribution to genome bulk. They thus contribute to the so-called “dark matter of the genome”, the part of the genome in which nothing is immediately recognizable as biologically functional.We developed a new method, based on k-mers, to identify degenerate TE sequences. With this new algorithm, we detect up to 10% of the A. thaliana genome as derived from as yet unidentified TEs, bringing the proportion of the genome known to be derived from TEs up to 50%. A significant proportion of these sequences overlapped conserved non-coding sequences identified in crucifers and rosids, and transcription factor binding sites. They are overrepresented in some gene regulation networks, such as the flowering gene network, suggesting a functional role for these sequences that have been conserved for more than 100 million years, since the spread of flowering plants in the Cretaceous.

2021 ◽  
Vol 6 (3) ◽  
pp. 126
Author(s):  
Gisele Strieder Philippsen

Transposable elements (TEs) are DNA sequences able to transpose within the host genome and, consequently, influence the dynamics of evolution in the species. Among the possible effects, TEs insertions may alter the expression and coding patterns of genes, leading to genomic innovations. Gene-duplication events, resulting from DNA segmental duplication induced by TEs transposition, constitute another important mechanism that contributes to the plasticity of genomes. This review aims to cover the current knowledge regarding TEs in the genome of the parasite Schistosoma mansoni, an agent of schistosomiasis—a neglected tropical disease affecting at least 250 million people worldwide. In this context, the literature concerning TEs description and TEs impact on the genomic architecture for S. mansoni was revisited, displaying evidence of TEs influence on schistosome speciation—mediated by bursts of transposition—and in gene-duplication events related to schistosome–host coevolution processes, as well several instances of TEs contribution into the coding sequences of genes. These findings indicate the relevant role of TEs in the evolution of the S. mansoni genome.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hee-Eun Lee ◽  
Sang-Je Park ◽  
Jae-Won Huh ◽  
Hiroo Imai ◽  
Heui-Soo Kim

AbstractTransposable elements (TEs) are DNA sequences that cut or introduced into the genome, and they represent a massive portion of the human genome. TEs generate a considerable number of microRNAs (miRNAs) are derived from TEs (MDTEs). Numerous miRNAs are related to cancer, and hsa-miRNA-625 is a well-known oncomiR derived from long interspersed nuclear elements (LINEs). The relative expression of hsa-miRNA-625-5p differs in humans, chimpanzees, crab-eating monkeys, and mice, and four primers were designed against the 3′UTR of GATAD2B to analyze the different quantities of canonical binding sites and the location of miRNA binding sites. Luciferase assay was performed to score for the interaction between hsa-miRNA-625 and the 3′UTR of GATAD2B, while blocking NF-κB. In summary, the different numbers of canonical binding sites and the locations of miRNA binding sites affect gene expression, and NF-κB induces the enhancer activity of hsa-miRNA-625-5p by sharing the binding sites.


2020 ◽  
Vol 17 (2) ◽  
pp. 133-147
Author(s):  
Mina Zafarpiran ◽  
Roya Sharifi ◽  
Zeinab Shirvani-Farsani

Background: Multiple Sclerosis (MS) is an inflammatory and demyelinating disease of the central nervous system, and genetic factors play an important role in its susceptibility. The expressions of many inflammatory genes implicated in MS are regulated by microRNA (miRNAs), whose function is to suppress the translation by pairing with miRNA Recognition Elements (MREs) present in the 3' untranslated region (3'UTR) of target mRNA. Recently, it has been shown that the Single Nucleotide Polymorphism (SNPs) present within the 3'UTR of mRNAs can affect the miRNA-mediated gene regulation and susceptibility to a variety of human diseases. Objective: The aim of this study was to analyze the SNPs within the 3'UTR of miRNA inflammatory target genes related to multiple sclerosis. Methods: By DisGeNET, dbGaP, Ovid, DAVID, Web of knowledge, and SNPs databases, 3'UTR genetic variants were identified in all inflammatory genes associated with MS. Also, miRNA's target prediction databases were used for predicting the miRNA binding sites. Results: We identified 125 SNPs with MAF>0.05 located in the binding site of the miRNA of 35 genes among 59 inflammatory genes related to MS. Bioinformatics analysis predicted 62 MRE-modulating SNPs and 59 MRE-creating SNPs in the 3'UTR of MSimplicated inflammatory genes. These candidate SNPs within miRNA binding sites of inflammatory genes can alter the miRNAs binding, and consequently lead to the mRNA gene regulation. Conclusion: Therefore, these miRNA and MRE-SNPs may play important roles in personalized medicine of MS, and hence, they would be valuable for further functional verification investigations.


2021 ◽  
Vol 49 (7) ◽  
pp. 3856-3875
Author(s):  
Marina Kulik ◽  
Melissa Bothe ◽  
Gözde Kibar ◽  
Alisa Fuchs ◽  
Stefanie Schöne ◽  
...  

Abstract The glucocorticoid (GR) and androgen (AR) receptors execute unique functions in vivo, yet have nearly identical DNA binding specificities. To identify mechanisms that facilitate functional diversification among these transcription factor paralogs, we studied them in an equivalent cellular context. Analysis of chromatin and sequence suggest that divergent binding, and corresponding gene regulation, are driven by different abilities of AR and GR to interact with relatively inaccessible chromatin. Divergent genomic binding patterns can also be the result of subtle differences in DNA binding preference between AR and GR. Furthermore, the sequence composition of large regions (>10 kb) surrounding selectively occupied binding sites differs significantly, indicating a role for the sequence environment in guiding AR and GR to distinct binding sites. The comparison of binding sites that are shared shows that the specificity paradox can also be resolved by differences in the events that occur downstream of receptor binding. Specifically, shared binding sites display receptor-specific enhancer activity, cofactor recruitment and changes in histone modifications. Genomic deletion of shared binding sites demonstrates their contribution to directing receptor-specific gene regulation. Together, these data suggest that differences in genomic occupancy as well as divergence in the events that occur downstream of receptor binding direct functional diversification among transcription factor paralogs.


Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1329-1338
Author(s):  
Peter A Peterson

Transposable elements in maize are composed of a defined molecular structure that includes coding sequences, determiners of functionality and ordered terminal motifs that provide binding sites for transposase proteins. Alterations in these components change the phenotypic expression of unstable genes with transposon inserts. The molecular basis for the altered timing and frequency of transposition as determined by the size and number of spots on kernels or stripes on leaves has generally been described for defective inserts in genes. Most differential patterns can be ascribed to alterations in the terminal motifs of the reporter allele structure that supplies a substrate (terminal inverted repeat motifs) for transposase activity. For autonomously functioning alleles, the explanations for changes in phenotype are not so clear. In this report, an En-related element identified as F-En is described that shares with En the recognition of a specific defective element c1(mr)888104 but differs from En in that this F-En element does not recognize the canonical c1(mr) elements that are recognized by En. Evidence is provided suggesting that F-En does not recognize other En/Spm-related defective elements, some of whose sequences are known. This modified En arose from a c1-m autonomously mutating En allele.


Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 118
Author(s):  
Arsala Ali ◽  
Kyudong Han ◽  
Ping Liang

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.


2003 ◽  
Vol 185 (4) ◽  
pp. 1326-1337 ◽  
Author(s):  
Philina S. Lee ◽  
Daniel Chi-Hong Lin ◽  
Shigeki Moriya ◽  
Alan D. Grossman

ABSTRACT Spo0J (ParB) of Bacillus subtilis is a DNA-binding protein that belongs to a conserved family of proteins required for efficient plasmid and chromosome partitioning in many bacterial species. We found that Spo0J contributes to the positioning of the chromosomal oriC region, but probably not by recruiting the origin regions to specific subcellular locations. In wild-type cells during exponential growth, duplicated origin regions were generally positioned around the cell quarters. In a spo0J null mutant, sister origin regions were often closer together, nearer to midcell. We found, by using a Spo0J-green fluorescent protein [GFP] fusion, that the subcellular location of Spo0J was a consequence of the chromosomal positions of the Spo0J binding sites. When an array of binding sites (parS sites) were inserted at various chromosomal locations in the absence of six of the eight known parS sites, Spo0J-GFP was no longer found predominantly at the cell quarters, indicating that Spo0J is not sufficient to recruit chromosomal parS sites to the cell quarters. spo0J also affected chromosome positioning during sporulation. A spo0J null mutant showed an increase in the number of cells with some origin-distal regions located in the forespore. In addition, a spo0J null mutation caused an increase in the number of foci per cell of LacI-GFP bound to arrays of lac operators inserted in various positions in the chromosome, including the origin region, an increase in the DNA-protein ratio, and an increase in origins per cell, as determined by flow cytometry. These results indicate that the spo0J mutant produced a significant proportion of cells with increased chromosome content, probably due to increased and asynchronous initiation of DNA replication.


BMC Genomics ◽  
2015 ◽  
Vol 16 (Suppl 13) ◽  
pp. S7 ◽  
Author(s):  
Konstantin Kozlov ◽  
Vitaly V Gursky ◽  
Ivan V Kulakovskiy ◽  
Arina Dymova ◽  
Maria Samsonova

1998 ◽  
Vol 18 (12) ◽  
pp. 7243-7258 ◽  
Author(s):  
Madhu Gupta ◽  
Radovan Zak ◽  
Towia A. Libermann ◽  
Mahesh P. Gupta

ABSTRACT The expression of the α-myosin heavy chain (MHC) gene is restricted primarily to cardiac myocytes. To date, several positive regulatory elements and their binding factors involved in α-MHC gene regulation have been identified; however, the mechanism restricting the expression of this gene to cardiac myocytes has yet to be elucidated. In this study, we have identified by using sequential deletion mutants of the rat cardiac α-MHC gene a 30-bp purine-rich negative regulatory (PNR) element located in the first intronic region that appeared to be essential for the tissue-specific expression of the α-MHC gene. Removal of this element alone elevated (20- to 30-fold) the expression of the α-MHC gene in cardiac myocyte cultures and in heart muscle directly injected with plasmid DNA. Surprisingly, this deletion also allowed a significant expression of the α-MHC gene in HeLa and other nonmuscle cells, where it is normally inactive. The PNR element required upstream sequences of the α-MHC gene for negative gene regulation. By DNase I footprint analysis of the PNR element, a palindrome of two high-affinity Ets-binding sites (CTTCCCTGGAAG) was identified. Furthermore, by analyses of site-specific base-pair mutation, mobility gel shift competition, and UV cross-linking, two different Ets-like proteins from cardiac and HeLa cell nuclear extracts were found to bind to the PNR motif. Moreover, the activity of the PNR-binding factor was found to be increased two- to threefold in adult rat hearts subjected to pressure overload hypertrophy, where the α-MHC gene is usually suppressed. These data demonstrate that the PNR element plays a dual role, both downregulating the expression of the α-MHC gene in cardiac myocytes and silencing the muscle gene activity in nonmuscle cells. Similar palindromic Ets-binding motifs are found conserved in the α-MHC genes from different species and in other cardiac myocyte-restricted genes. These results are the first to reveal a role of the Ets class of proteins in controlling the tissue-specific expression of a cardiac muscle gene.


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