Malignant Transformation Drives DNA Methylation Loss and Transcriptional Activation of Transposable Element Loci [WGBS]
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ABSTRACT:
PROVIDER: PRJNA967674 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR24446471_1.fastq.gz | Fastqsanger.gz | |||
| SRR24446471_2.fastq.gz | Fastqsanger.gz | |||
| SRR24446472_1.fastq.gz | Fastqsanger.gz | |||
| SRR24446472_2.fastq.gz | Fastqsanger.gz | |||
| SRR24446473.fastq.gz | Fastqsanger.gz |
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Project description:Transposable elements (TEs) are typically silenced by DNA methylation and repressive histone modifications in differentiated healthy human tissues. However, TE expression increases in a wide range of cancers and is correlated with global hypomethylation of cancer genomes. We assessed expression and DNA methylation of TEs in fibroblast cells that were serially transduced with hTERT, SV40, and HRASR24C to immortalize and then transform them, which models the different steps of the tumorigenesis process. RNA-sequencing and whole-genome bisulfite sequencing were performed at each stage of transformation. TE expression significantly increased as cells progressed through transformation, with the largest increase in expression after the final stage of transformation, consistent with data from human tumors. The upregulated TEs were dominated by endogenous retroviruses (LTRs). Most differentially methylated regions (DMRs) in all stages were hypomethylated, with the greatest hypomethylation in the final stage of transformation. A majority of the DMRs overlapped TEs from the RepeatMasker database, indicating that TEs are preferentially demethylated. Many hypomethylated TEs displayed a concordant increase in expression. Demethylation began during immortalization and continued into transformation, while upregulation of TE transcription occurred in transformation. Numerous LTR elements upregulated in the model were also identified in TCGA datasets of breast, colon, and prostate cancer. Overall, these findings indicate that transposable elements, specifically endogenous retroviruses, are demethylated and transcribed during transformation.
2023-06-28 | GSE231778 | GEO
Project description:Malignant Transformation Drives DNA Methylation Loss and Transcriptional Activation of Transposable Element Loci
| PRJNA967669 | ENA
Project description:Background: The small RNAs that Transposable Elements generate are vastly different when they are transcriptionally silenced compared to when they are transcriptionally activated. We performed the deep sequencing of small RNAs in a number of small RNA biogenesis mutants in both Transposable Element-silenced and Transposable Element-active epigenome backgrounds. Results: We found that Transposable Elements generate large amounts of 21-22nt siRNAs only when they are transcriptionally active. These 21-22nt siRNAs are incorporated into the AGO6 protein. Conclusion: Ago6 is the key protein that bridges the post-transcriptional degradation of Transposable Element mRNAs and the establishment of DNA methylation. Examination of flower bud small RNAs from wild type and 5 single or double mutant combinations, many of which have biological replicates. In addition, IP purification of the AGO6 protein (and mock no-antigen controls) followed by sequencing of the incorporated small RNAs. Replicate A for Col and ddm1 are submitted in GSE41755
2014-11-14 | E-GEOD-57191 | biostudies-arrayexpress
Project description:Background: The small RNAs that Transposable Elements generate are vastly different when they are transcriptionally silenced compared to when they are transcriptionally activated. We performed the deep sequencing of small RNAs in a number of small RNA biogenesis mutants in both Transposable Element-silenced and Transposable Element-active epigenome backgrounds. Results: We found that Transposable Elements generate large amounts of 21-22nt siRNAs only when they are transcriptionally active. These 21-22nt siRNAs are incorporated into the AGO6 protein. Conclusion: Ago6 is the key protein that bridges the post-transcriptional degradation of Transposable Element mRNAs and the establishment of DNA methylation.
2014-11-14 | GSE57191 | GEO
Project description:Background: Transposable element 24 nucleotide small RNAs are not efficiently incorporated into the AGO1 protein, which is involved in endogenous RNAi and gene regulation through the microRNA and tasiRNA pathways. Results: The AGO1 protein incorporates large quantities of transposable element siRNAs when transposable elements are epigenetically activated and transcribed. The incorporation of transposable element siRNAs is at the expense of the most abundant microRNAs. These transposable element siRNAs can act as tasiRNAs, regulating genes that they have partial complementarity to. Conclusion: Transposable element small RNAs are more dynamic than previously thought. They can be incorporated into AGO1 and regulate genes. Three biological replicates of small RNA sequencing from two genotypes
2014-04-07 | E-GEOD-45990 | biostudies-arrayexpress
Project description:Epigenomic conservation of transposable element silencing
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Project description:Background: Transposable element 24 nucleotide small RNAs are not efficiently incorporated into the AGO1 protein, which is involved in endogenous RNAi and gene regulation through the microRNA and tasiRNA pathways. Results: The AGO1 protein incorporates large quantities of transposable element siRNAs when transposable elements are epigenetically activated and transcribed. The incorporation of transposable element siRNAs is at the expense of the most abundant microRNAs. These transposable element siRNAs can act as tasiRNAs, regulating genes that they have partial complementarity to. Conclusion: Transposable element small RNAs are more dynamic than previously thought. They can be incorporated into AGO1 and regulate genes.
2014-04-07 | GSE45990 | GEO
Project description:Background: Transposable elements are known to influence the regulation of some genes. We aimed to determine which genes show altered gene expression when transposable elements are epigenetically activated. Results: We find over 2000 genes with altered steady-state expression levels in ddm1 mutants. Some of these genes are influenced by neighboring transposable element fragments, while other genes are targeted by transposable element derived 21 nucleotide siRNAs. Conclusion: The regulation of the genic portion of the Arabidopsis genome is heavily influenced by the epigenetic regulation of transposable elements. The regulation of genes by transposable elements can occur through multiple mechanisms. Three biological replicates for two genotypes
2014-04-07 | E-GEOD-46050 | biostudies-arrayexpress
Project description:Transposable elements (TEs) are typically silenced by DNA methylation and repressive histone modifications in differentiated healthy human tissues. However, TE expression increases in a wide range of cancers and is correlated with global hypomethylation of cancer genomes. We assessed expression and DNA methylation of TEs in fibroblast cells that were serially transduced with hTERT, SV40, and HRASR24C to immortalize and then transform them, which models the different steps of the tumorigenesis process. RNA-sequencing and whole-genome bisulfite sequencing were performed at each stage of transformation. TE expression significantly increased as cells progressed through transformation, with the largest increase in expression after the final stage of transformation, consistent with data from human tumors. The upregulated TEs were dominated by endogenous retroviruses (LTRs). Most differentially methylated regions (DMRs) in all stages were hypomethylated, with the greatest hypomethylation in the final stage of transformation. A majority of the DMRs overlapped TEs from the RepeatMasker database, indicating that TEs are preferentially demethylated. Many hypomethylated TEs displayed a concordant increase in expression. Demethylation began during immortalization and continued into transformation, while upregulation of TE transcription occurred in transformation. Numerous LTR elements upregulated in the model were also identified in TCGA datasets of breast, colon, and prostate cancer. Overall, these findings indicate that transposable elements, specifically endogenous retroviruses, are demethylated and transcribed during transformation.
2023-06-28 | GSE231776 | GEO
Project description:Investigation of the effect of the knockdown of AT-hook motif DNA binding nuclear matrix protein TRANSPOSABLE ELEMENT KILLER (TEK) in the Arabidopsis Landsberg erecta (Ler) background Transposable elements (TEs) are silenced by epigenetic mechanisms of DNA and histone methylation. The repressive histone modification H3 lysine 9 dimethylation (H3K9me2) is TE-associated epigenetic hallmark, and is necessary for DNA methylation. However the mechanism to direct the repressive epigenetic modification in TEs has remained elusive. Here we show that knockdown of the AT-hook motif DNA binding nuclear matrix protein TRANSPOSABLE ELEMENT KILLER (TEK) in the Arabidopsis Landsberg erecta (Ler) background results in robust activation of various TEs, the repeat-containing floral repressor gene FWA and the TE-containing floral repressor FLOWERING LOCUS C (FLC). A four chip study using two separate wild-type seedling mRNA samples and two separate TEKi seedling mRNA samples
2012-09-12 | E-GEOD-39158 | biostudies-arrayexpress