TE-Array-- A high throughput tool to study transposon transcription
Ontology highlight
ABSTRACT: TE-Array is a custom Agilent microarray that probes for transposable elements in both sense and antisense orientations in humans and mice. TE-Array was used to study expression levels of transposable elements (TE) in a panel of normal mouse tissues. TE-Array comprises of 4 different custom Agilent 4X44K designs. These 4 different designs have probes for human sense orientation, human antisense orientation, mouse sense orientation and mouse antisense orientation transposable elements. These array designs were used to study the transposon abundance profile in 7 different mouse tissue samples, 2 mouse cell lines and 1 transposon transfected versus untransfected human cell line.
Project description:TE-Array is a custom Agilent microarray that probes for transposable elements in both sense and antisense orientations in humans and mice. TE-Array was used to study expression levels of transposable elements (TE) in a panel of normal mouse tissues.
Project description:To validate the 244K 60-mer probes using a custom-designed Agilent oligo array and assuming sense orientation of all target sequences. A total of four test arrays were designed assuming both sense and antisense orientations. A sole pooled RNA was used for testing all 4 designs. Two arrays were hybridized for each design. This series contains test results for design 2520022.
Project description:To validate the 244K 60-mer probes using a custom-designed Agilent oligo array and assuming antisense orientation of all target sequences. A total of four test arrays were designed assuming both sense and antisense orientations. A sole pooled RNA was used for testing all 4 designs. Two arrays were hybridized for each design. This series contains test results for design 2520023.
Project description:To validate the 244K 60-mer or 40-mer probes using a custom-designed Agilent oligo array and assuming sense orientation of all target sequences. A total of four test arrays were designed assuming both sense and antisense orientations. A sole pooled RNA was used for testing all 4 designs. Two arrays were hybridized for each design. This series contains test results for design 2520024.
Project description:To validate the 244K 60-mer or 40-mer probes using a custom-designed Agilent oligo array and assuming antisense orientation of all target sequences. A total of four test arrays were designed assuming both sense and antisense orientations. A sole pooled RNA was used for testing all 4 designs. Two arrays were hybridized for each design. This series contains test results for design 2520025.
Project description:DNA methylation and other repressive epigenetic marks are erased in the mammalian germline and transposable elements (TEs) acquire the potential to be transcribed. This is a critical phase for genome defense and complementary TE silencing pathways are required to limit their activity. We find overlapping sense/antisense transcription in TEs in mouse embryonic stem cells, with an increase of sense transcription induced by acute deletion of Dnmt1, leading to increased abundance of small RNAs. These small RNAs are loaded into ARGONAUTE2 (AGO2) suggesting an endosiRNA based silencing mechanism. Reduction of Dicer and Ago2 levels reveals that small RNAs are involved in an immediate response to transposon activation by demethylation, while the deposition of repressive histone marks represents an ensuing chronic response. Dicer dependent endosiRNAs which map to TEs are also found in vivo during primordial germ cell development. Our results suggest that TE antisense transcription acts as a trap that restrains acute transposon activity through small RNAs during epigenetic reprogramming in the germline.
Project description:DNA methylation and other repressive epigenetic marks are erased in the mammalian germline and transposable elements (TEs) acquire the potential to be transcribed. This is a critical phase for genome defense and complementary TE silencing pathways are required to limit their activity. We find overlapping sense/antisense transcription in TEs in mouse embryonic stem cells, with an increase of sense transcription induced by acute deletion of Dnmt1, leading to increased abundance of small RNAs. These small RNAs are loaded into ARGONAUTE2 (AGO2) suggesting an endosiRNA based silencing mechanism. Reduction of Dicer and Ago2 levels reveals that small RNAs are involved in an immediate response to transposon activation by demethylation, while the deposition of repressive histone marks represents an ensuing chronic response. Dicer dependent endosiRNAs which map to TEs are also found in vivo during primordial germ cell development. Our results suggest that TE antisense transcription acts as a trap that restrains acute transposon activity through small RNAs during epigenetic reprogramming in the germline.
Project description:DNA methylation and other repressive epigenetic marks are erased in the mammalian germline and transposable elements (TEs) acquire the potential to be transcribed. This is a critical phase for genome defense and complementary TE silencing pathways are required to limit their activity. We find overlapping sense/antisense transcription in TEs in mouse embryonic stem cells, with an increase of sense transcription induced by acute deletion of Dnmt1, leading to increased abundance of small RNAs. These small RNAs are loaded into ARGONAUTE2 (AGO2) suggesting an endosiRNA based silencing mechanism. Reduction of Dicer and Ago2 levels reveals that small RNAs are involved in an immediate response to transposon activation by demethylation, while the deposition of repressive histone marks represents an ensuing chronic response. Dicer dependent endosiRNAs which map to TEs are also found in vivo during primordial germ cell development. Our results suggest that TE antisense transcription acts as a trap that restrains acute transposon activity through small RNAs during epigenetic reprogramming in the germline.
Project description:Background: Transposable elements (TEs) represent a substantial fraction of the genomes, playing a major role in evolution, as sources of genetic variability. To fully appraise the role of TE in the acquisition of genetic novelty in genome evolution, we must also consider the impact of their own transcriptional activity. Results: We studied impact of TE transcriptional activity on gene using high-throughput RNA-Seq sequencing in Drosophila melanogaster. TEs, which turn out to be expressed in euchromatin as well as in heterochromatin, interact with genes at different levels. The observed transcription from TEs involve canonical or non-canonical transcription start sites (TSSs) distributed along their sequence. We also find evidences for potential bidirectional transcription from the TE promoter regions where the antisense transcript is co-opted by the host genome as TSSs of a gene. We found that active TEs seem to accumulate in the 5' upstream regions of the genes, and possibly provide an alternative transcript of the nearby gene. Indeed, predominantly, the TE transcript is collinear and overlapping the gene. Apart from the 5' upstream regions, we also found that most active TEs are transcribed on the gene transcript strand. Conversely, few transcripts from TE are anti sense with respect to the gene. This suggests that they have a disruptive action and are counter-selected. The only exceptions are for TEs located into introns, where they could provide another complex way of gene regulation, and in the 3' downstream region, where other mechanisms akin to siRNAs could take place. Finally, we noted several cases where the cryptic TSS is located on TE fragments corresponding to a low complexity sequence. Frequently these TE fragments appear to be over-represented when close to genes, suggesting a possible selected role. Conclusion: Altogether, these results suggest that active transposable elements influence host gene transcription. It is likely that some features of transposable elements have been exaptated in order to enrich the genes repertoire by opening routes to sub- or neo-functionalization. Examination of the transcription produced by transposable elements in D. melanogaster
Project description:Maize RNA Polymerase D1 (RPD1), the largest subunit of RNA polymerase IV (Pol IV), is required for normal plant development, repression of transposable elements (TEs), and for the regulation of specific alleles associated with TEs. Here, we define the nascent transcriptomes of rpd1 mutant and wild-type (WT) seedlings using global run-on sequencing (GRO-seq) to identify the broader targets of RPD1-based transcriptional regulation. Surprisingly, although TE-like sequences comprise >85% of the maize genome, most TEs are not transcribed at the seedling stage, even in rpd1 mutants. Profile comparisons identify the global set of genes and TEs whose transcription is altered in the absence of RPD1, in some cases in antisense orientation. These results indicate that maize Pol IV specifies Pol II-based transcriptional regulation for certain regions of the maize genome. Nuclei isolated from 10 wild-type and 10 rpd1 mutant seedlings were pooled and used to make two global run-on sequencing libraries.