Mapping meiotic crossovers in Arabidopsis using low-coverage whole-genome sequencing
Ontology highlight
ABSTRACT: Whole-genome DNA libraries were prepared from a population of just under 100 Col/Ler F1 backcrossed to Col. Low-coverage whole-genome sequencing was used to map meiotic crossovers in this population following the protocol described in Rowan et al., 2015, doi: 10.1534/g3.114.016501.
Project description:Genomic DNA from 180 Col/Bur F2 individuals, and 186 taf4b/Bur F2 individuals, was extracted by CTAB and used to generate sequencing libraries as previously described (Ziolkowski et al, 2017 Genes & Dev). Sequencing data was analysed to identify crossovers using the TIGER pipeline as previously described (Rowan et al, 2015 G3 (Bethesda); Yelina et al, 2015 Genes & Dev).
Project description:Genomic DNA from 189 wild type Col x CLC, 191 msh2 Col x CLC or 187 msh2 Col x Ler F2 individuals was extracted using CTAB and used to generate sequencing libraries as described (Serra et al 2018 PNAS). Sequencing data was analysed to identify crossovers as previously reported, using the TIGER pipeline (Rowan et al., 2015 G3).
Project description:Genomic DNA from 192 recq4a recq4b and 192 HEI10 recq4a recq4b Col x Ler F2 individuals was extracted using CTAB and used to generate sequencing libraries as described (Ziolkowski et al, 2017 Genes & Dev). Sequencing data was analysed to identify crossovers as previously reported, using the TIGER pipeline (Rowan et al, 2015 G3 (Bethesda); Yelina et al, 2015 Genes & Dev).
Project description:Genomic DNA from 74 wild type Col x Ler F2 individuals was extracted using CTAB and used to generate sequencing libraries as described (Rowan et al; Yelina et al), with the following modifications. DNA was extracted from 3 rosette leaves of 5 week old plants and 150 ng of DNA used as input for each library. DNA shearing was carried out for 20 minutes at 37C with 0.4U of DNA Shearase (Zymo research). The barcoded adapters used for library construction are listed in Rowan et al. Each set of 96 libraries was sequenced on one lane of an Illumina NextSeq500 instrument (300-cycle Mid Output run). Sequencing data were analyzed to identify crossovers as previously reported, using the TIGER pipeline (Rowan et al; Yelina et al).
Project description:The pioneer interactions between incoming viral RNA genomes and host proteins are crucial to infection and immune response. Until now, the ability to study these events was lacking. We developed VIR-CLASP (VIRal Cross-Linking And Solid-phase Purification) to characterize the earliest interactions between viral RNA and cellular proteins. We investigated the infection of human cells using Chikungunya virus (CHIKV) and Influenza A virus and identified hundreds of direct RNA-protein interactions. Here, we validate the biological impact of three protein classes that bind CHIKV RNA within minutes of infection. We find CHIKV RNA binds and hijacks the lipid-modifying enzyme FASN for pro-viral activity. We show that CHIKV genomes are N6-methyladenosine modified and that YTHDF1 binds and suppresses its replication. Finally, we find that the innate immune DNA sensor IFI16 associates with CHIKV RNA, reducing viral replication and maturation. Our findings have direct applicability to the investigation of potentially all RNA viruses.
Project description:Projected responses of ocean net primary productivity (NPP) to climate change are highly uncertain. The climate sensitivity of phytoplankton nutrient limitation in the low-latitude Pacific plays a crucial role, but field measurements are insufficient to provide suitable constraints. Here we quantify two decades of nutrient limitation in the Equatorial Pacific with satellite observations. Using field nutrient addition experiments, proteomics, and above-water hyperspectral radiometry, we demonstrate that physiological responses of phytoplankton to iron limitation led to ~3-fold increases in chlorophyll-normalized phytoplankton fluorescence. Extension to the >18-year satellite fluorescence record showed that Equatorial Pacific iron limitation was robust to changes in physical forcing through multiple El Niño–Southern Oscillation cycles, despite coherent fluctuations in limitation strength. In contrast, these iron limitation changes were overestimated 2-fold by a state-of-the-art climate model. Such synoptic constraints provide a powerful new approach for benchmarking the realism of model NPP projections to climate changes.
Project description:High-throughput and streamlined workflows are essential in clinical proteomics for standardized processing of samples originating from a variety of sources, including frozen tissue, FFPE tissue, or blood. To reach this goal, we have implemented single-pot solid-phase-enhanced sample preparation (SP3) on a liquid handling robot for automated processing (autoSP3) of tissue lysates in a 96-well format, performing unbiased protein purification and digestion delivering peptides that can be directly analyzed by LCMS. AutoSP3 eliminates hands-on time and minimizes the risk of error, and we show it reduces the protein quantification variability, and improves longitudinal performance and reproducibility. We demonstrate the distinguishing ability of autoSP3 to process low-input samples, reproducibly quantifying 500-1000 proteins from 100-1000 cells (<100 ng protein). Furthermore we applied it to process a cohort of clinical FFPE pulmonary adenocarcinoma (ADC) samples, and recapitulate their separation into known histological growth patterns based on proteome profiles. Collectively, autoSP3 provides a generic, scalable, and cost-effective pipeline for routine and standardized proteomic sample processing that should enable reproducible proteomics in broad range of clinical and non-clinical applications.
Project description:Through the analysis of mouse liver tumours promoted by distinct routes (DEN exposure alone, DEN exposure plus non-genotoxic insult with phenobarbital and non-alcoholic fatty liver disease); we report that the cancer associated hyper-methylated CGI events in mice are also predicated by silent promoters that are enriched for both the DNA modification 5-hydroxymethylcytosine (5hmC) and the histone modification H3K27me3 in normal liver. During cancer progression these CGIs undergo hypo-hydroxymethylation, prior to subsequent hyper-methylation; whilst retaining H3K27me3. A similar loss of promoter-core 5hmC is observed in Tet1 deficient mouse livers indicating that reduced Tet1 binding at CGIs may be responsible for the epigenetic dysregulation observed during hepatocarcinogenesis. Consistent with this reduced Tet1 protein levels are observed in mouse liver tumour lesions. As in human, DNA methylation changes at CGIs do not appear to be direct drivers of hepatocellular carcinoma progression in mice. Instead dynamic changes in H3K27me3 promoter deposition are strongly associated with tumour-specific activation and repression of transcription. Our data suggests that loss of promoter associated 5hmC in diverse liver tumours licences DNA methylation reprogramming at silent CGIs during cancer progression. 5-mc is a well establisehd epigenetic mark typically related to gene silencing events. Phenobarbital (PB) is a well studied non-genotoxic carcinogen with roles in epigenetic perturbation. We profile 5mC in both control mouse livers as well as in liver tumours of high fat diet exposed mice who have progressed through NASH. Samples: 5mC profiles in livers of 2 control and 2 NASH driven HCC samples
Project description:Through the analysis of mouse liver tumours promoted by distinct routes (DEN exposure alone, DEN exposure plus non-genotoxic insult with phenobarbital and non-alcoholic fatty liver disease); we report that the cancer associated hyper-methylated CGI events in mice are also predicated by silent promoters that are enriched for both the DNA modification 5-hydroxymethylcytosine (5hmC) and the histone modification H3K27me3 in normal liver. During cancer progression these CGIs undergo hypo-hydroxymethylation, prior to subsequent hyper-methylation; whilst retaining H3K27me3. A similar loss of promoter-core 5hmC is observed in Tet1 deficient mouse livers indicating that reduced Tet1 binding at CGIs may be responsible for the epigenetic dysregulation observed during hepatocarcinogenesis. Consistent with this reduced Tet1 protein levels are observed in mouse liver tumour lesions. As in human, DNA methylation changes at CGIs do not appear to be direct drivers of hepatocellular carcinoma progression in mice. Instead dynamic changes in H3K27me3 promoter deposition are strongly associated with tumour-specific activation and repression of transcription. Our data suggests that loss of promoter associated 5hmC in diverse liver tumours licences DNA methylation reprogramming at silent CGIs during cancer progression. 5-mc is a well establisehd epigenetic mark typically related to gene silencing events. Phenobarbital (PB) is a well studied non-genotoxic carcinogen with roles in epigenetic perturbation. We profile 5mC in both control mouse livers as well as in the livers of 12 week PB treated mice. We also profile 5mC in liver tumours arising in the presence of long term PB exposure (35 week: resulting in Ctnnb1 mutated tumours) to a Ha-Ras liver tumour which arose without PB. Samples: 2 control and 2 PB exposed mouse livers, 3 liver tumours resulting from long term PB exposrue and 1 liver tumour arising without PB
Project description:Through the analysis of mouse liver tumours promoted by distinct routes (DEN exposure alone, DEN exposure plus non-genotoxic insult with phenobarbital and non-alcoholic fatty liver disease); we report that the cancer associated hyper-methylated CGI events in mice are also predicated by silent promoters that are enriched for both the DNA modification 5-hydroxymethylcytosine (5hmC) and the histone modification H3K27me3 in normal liver. During cancer progression these CGIs undergo hypo-hydroxymethylation, prior to subsequent hyper-methylation; whilst retaining H3K27me3. A similar loss of promoter-core 5hmC is observed in Tet1 deficient mouse livers indicating that reduced Tet1 binding at CGIs may be responsible for the epigenetic dysregulation observed during hepatocarcinogenesis. Consistent with this reduced Tet1 protein levels are observed in mouse liver tumour lesions. As in human, DNA methylation changes at CGIs do not appear to be direct drivers of hepatocellular carcinoma progression in mice. Instead dynamic changes in H3K27me3 promoter deposition are strongly associated with tumour-specific activation and repression of transcription. Our data suggests that loss of promoter associated 5hmC in diverse liver tumours licences DNA methylation reprogramming at silent CGIs during cancer progression. 5-hmC is a novel epigenetic mark derived from oxidation of methylcytosine. Phenobarbital (PB) is a well studied non-genotoxic carcinogen with roles in epigenetic perturbation. We profile 5hmC in both control mouse livers as well as in the livers of 12 week PB treated mice. We also profile 5hmC in liver tumours arising in the presence of long term PB exposure (35 week: resulting in Ctnnb1 mutated tumours) to a Ha-Ras liver tumour which arose without PB. Samples: 5hmC profiles in 2 control and 2 PB exposed mouse livers, 3 liver tumours resulting from long term PB exposrue and 1 liver tumour arising without PB