Limited impact of the siRNA pathway on transposable element expression in Aedes aegypti [ncRNA-seq]
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ABSTRACT:
PROVIDER: PRJNA1153542 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR30446722.fastq.gz | Fastqsanger.gz | |||
| SRR30446723.fastq.gz | Fastqsanger.gz | |||
| SRR30446724.fastq.gz | Fastqsanger.gz | |||
| SRR30446725.fastq.gz | Fastqsanger.gz | |||
| SRR30446726.fastq.gz | Fastqsanger.gz |
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Project description:Transposable elements (TEs) are DNA sequences that can change their position within a genome. In the germline of arthropods, post-transcriptional regulation of TE expression is mainly mediated by the Piwi-interacting RNA (piRNA) pathway. piRNAs are small RNAs of 24-30 nucleotides (nt) in length produced from genomic precursor transcripts as well as through a ‘ping-pong’ amplification cycle. In somatic tissues, certain insects, such as Drosophila, instead rely on the small interfering RNA (siRNA) pathway as a key regulator of TE expression. siRNAs are 21nt small RNAs produced from double-stranded RNA by the endonuclease Dicer2, which guides an RNA-induced silencing complex to degrade a complementary RNA. However, whether the siRNA pathway also regulates TE expression in the mosquito Aedes aegypti, a medically significant vector species with abundant somatic piRNAs, is unknown. To address this question, we investigated the expression of TEs and small RNAs in both somatic and gonadal tissues of a Dicer2 mutant line of Ae. aegypti and its wild-type counterpart. Our results show a modified pattern of TE expression and a decrease in TE-derived 21nt small RNAs in the Dicer2 mutant, but no major shift of TE transcript abundance. The lack of a functional siRNA pathway also causes perturbations in piRNA ping-pong signatures and the expression of certain piRNA-associated genes, but without clear evidence for compensation by increased piRNA pathway activity. We conclude that the mosquito Ae. aegypti produces siRNAs targeting TEs but these lack a critical role in the regulation of TE expression both in somatic and in gonadal tissues.
2025-04-09 | GSE275903 | GEO
Project description:Transposable elements (TEs) are DNA sequences that can change their position within a genome. In the germline of arthropods, post-transcriptional regulation of TE expression is mainly mediated by the Piwi-interacting RNA (piRNA) pathway. piRNAs are small RNAs of 24-30 nucleotides (nt) in length produced from genomic precursor transcripts as well as through a ‘ping-pong’ amplification cycle. In somatic tissues, certain insects, such as Drosophila, instead rely on the small interfering RNA (siRNA) pathway as a key regulator of TE expression. siRNAs are 21nt small RNAs produced from double-stranded RNA by the endonuclease Dicer2, which guides an RNA-induced silencing complex to degrade a complementary RNA. However, whether the siRNA pathway also regulates TE expression in the mosquito Aedes aegypti, a medically significant vector species with abundant somatic piRNAs, is unknown. To address this question, we investigated the expression of TEs and small RNAs in both somatic and gonadal tissues of a Dicer2 mutant line of Ae. aegypti and its wild-type counterpart. Our results show a modified pattern of TE expression and a decrease in TE-derived 21nt small RNAs in the Dicer2 mutant, but no major shift of TE transcript abundance. The lack of a functional siRNA pathway also causes perturbations in piRNA ping-pong signatures and the expression of certain piRNA-associated genes, but without clear evidence for compensation by increased piRNA pathway activity. We conclude that the mosquito Ae. aegypti produces siRNAs targeting TEs but these lack a critical role in the regulation of TE expression both in somatic and in gonadal tissues.
2025-04-09 | GSE275899 | GEO
Project description:Limited impact of the siRNA pathway on transposable element expression in Aedes aegypti [RNA-seq]
| PRJNA1153541 | ENA
Project description:Background: The piRNA pathway has been shown in model organisms to be involved in silencing of transposons thereby providing genome stability. In D. melanogaster the majority of piRNAs map to these sequences. The medically important mosquito species Aedes aegypti has a large genome size, a high transposon load which includes Miniature Inverted repeat Transposable Elements (MITES) and an expansion of the piRNA biogenesis genes. Studies of transgenic lines of Ae. aegypti have indicated that introduced transposons are poorly remobilized and we sought to explore the basis of this. We wished to analyze the piRNA profile of Ae. aegypti and thereby determine if it be responsible for transposon silencing in this mosquito. Results: Estimated piRNA sequence diversity was comparable between Ae. aegypti and D. melanogaster, but surprisingly only 19% of mosquito piRNAs mapped to transposons compared to 51% for D. melanogaster. Ae. aegypti piRNA clusters made up a larger percentage of the total genome than those of D. melanogaster but did not contain significantly higher percentages of transposon derived sequences than other regions of the genome. Ae. aegypti contains a number of protein coding genes that may be sources of piRNA biogenesis with two, traffic jam and maelstrom, implicated in this process in model organisms. Several genes of viral origin were also targeted by piRNAs. Examination of six mosquito libraries that had previously been transformed with transposon derived sequence revealed that new piRNA sequences had been generated to the transformed sequences, suggesting that they may have stimulated a transposon inactivation mechanism. Conclusions: Ae. aegypti has a large piRNA complement that maps to transposons but primarily gene sequences, including many viral-derived sequences. This, together the more uniform distribution of piRNA clusters throughout its genome suggest that some aspects of the piRNA system differ between Ae. aegypti and D. melanogaster. 5 small RNA libraries were generated from total RNA of whole adult Aedes aegypti tissues, two of these libraries were sequenced twice (technical replicates). 1 small RNA library was generated from total RNA of a whole adult Drosophila melanogaster tissue.
2014-03-18 | E-GEOD-33595 | biostudies-arrayexpress
Project description:Background: The piRNA pathway has been shown in model organisms to be involved in silencing of transposons thereby providing genome stability. In D. melanogaster the majority of piRNAs map to these sequences. The medically important mosquito species Aedes aegypti has a large genome size, a high transposon load which includes Miniature Inverted repeat Transposable Elements (MITES) and an expansion of the piRNA biogenesis genes. Studies of transgenic lines of Ae. aegypti have indicated that introduced transposons are poorly remobilized and we sought to explore the basis of this. We wished to analyze the piRNA profile of Ae. aegypti and thereby determine if it be responsible for transposon silencing in this mosquito. Results: Estimated piRNA sequence diversity was comparable between Ae. aegypti and D. melanogaster, but surprisingly only 19% of mosquito piRNAs mapped to transposons compared to 51% for D. melanogaster. Ae. aegypti piRNA clusters made up a larger percentage of the total genome than those of D. melanogaster but did not contain significantly higher percentages of transposon derived sequences than other regions of the genome. Ae. aegypti contains a number of protein coding genes that may be sources of piRNA biogenesis with two, traffic jam and maelstrom, implicated in this process in model organisms. Several genes of viral origin were also targeted by piRNAs. Examination of six mosquito libraries that had previously been transformed with transposon derived sequence revealed that new piRNA sequences had been generated to the transformed sequences, suggesting that they may have stimulated a transposon inactivation mechanism. Conclusions: Ae. aegypti has a large piRNA complement that maps to transposons but primarily gene sequences, including many viral-derived sequences. This, together the more uniform distribution of piRNA clusters throughout its genome suggest that some aspects of the piRNA system differ between Ae. aegypti and D. melanogaster.
2014-03-18 | GSE33595 | GEO
Project description:The incomplete genome annotation of non-model organisms hampers molecular and proteomic studies. Proteomics informed by transcriptomics (PIT) is suited to non-model organisms because peptides are identified using transcriptomic, not genomic, data. Aedes aegypti is the mosquito vector for the (re-)emerging dengue, chikungunya, yellow fever and Zika viruses. An Ae. aegypti genome sequence is available, however experimental evidence for >90% of the Ae. aegypti proteome or the activity of transposable elements (TEs) that constitute 50% of the Ae. aegypti genome is lacking. We used PIT to characterise the proteome of the Aedes aegypti derived cell line Aag2. Hotspots of incomplete genome annotation were identified which are not explained by poor sequence and assembly quality. We developed criteria for the characterisation of proteomically active TEs and demonstrate that protein expression does not correlate with a TE’s genomic abundance. Finally, we identify Phasi Charoen-like virus as an unrecognised contaminant of Aag2 cells. We therefore present the first proteomic characterisation of mobile genetic elements, and provide proof-of-principle that PIT can evaluate a genome’s annotation to guide annotation efforts.
2017-02-15 | PXD003799 | Pride
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: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