--- _id: '12192' abstract: - lang: eng text: Transposable elements (TEs), the movement of which can damage the genome, are epigenetically silenced in eukaryotes. Intriguingly, TEs are activated in the sperm companion cell – vegetative cell (VC) – of the flowering plant Arabidopsis thaliana. However, the extent and mechanism of this activation are unknown. Here we show that about 100 heterochromatic TEs are activated in VCs, mostly by DEMETER-catalyzed DNA demethylation. We further demonstrate that DEMETER access to some of these TEs is permitted by the natural depletion of linker histone H1 in VCs. Ectopically expressed H1 suppresses TEs in VCs by reducing DNA demethylation and via a methylation-independent mechanism. We demonstrate that H1 is required for heterochromatin condensation in plant cells and show that H1 overexpression creates heterochromatic foci in the VC progenitor cell. Taken together, our results demonstrate that the natural depletion of H1 during male gametogenesis facilitates DEMETER-directed DNA demethylation, heterochromatin relaxation, and TE activation. acknowledgement: We thank David Twell for the pDONR-P4-P1R-pLAT52 and pDONR-P2R-P3-mRFP vectors, the John Innes Centre Bioimaging Facility (Elaine Barclay and Grant Calder) for their assistance with microscopy, and the Norwich BioScience Institute Partnership Computing infrastructure for Science Group for High Performance Computing resources. This work was funded by a Biotechnology and Biological Sciences Research Council (BBSRC) David Phillips Fellowship (BB/L025043/1; SH, JZ and XF), a European Research Council Starting Grant ('SexMeth' 804981; XF) and a Grant to Exceptional Researchers by the Gatsby Charitable Foundation (SH and XF). article_number: '42530' article_processing_charge: No article_type: original author: - first_name: Shengbo full_name: He, Shengbo last_name: He - first_name: Martin full_name: Vickers, Martin last_name: Vickers - first_name: Jingyi full_name: Zhang, Jingyi last_name: Zhang - first_name: Xiaoqi full_name: Feng, Xiaoqi id: e0164712-22ee-11ed-b12a-d80fcdf35958 last_name: Feng orcid: 0000-0002-4008-1234 citation: ama: He S, Vickers M, Zhang J, Feng X. Natural depletion of histone H1 in sex cells causes DNA demethylation, heterochromatin decondensation and transposon activation. eLife. 2019;8. doi:10.7554/elife.42530 apa: He, S., Vickers, M., Zhang, J., & Feng, X. (2019). Natural depletion of histone H1 in sex cells causes DNA demethylation, heterochromatin decondensation and transposon activation. ELife. eLife Sciences Publications, Ltd. https://doi.org/10.7554/elife.42530 chicago: He, Shengbo, Martin Vickers, Jingyi Zhang, and Xiaoqi Feng. “Natural Depletion of Histone H1 in Sex Cells Causes DNA Demethylation, Heterochromatin Decondensation and Transposon Activation.” ELife. eLife Sciences Publications, Ltd, 2019. https://doi.org/10.7554/elife.42530. ieee: S. He, M. Vickers, J. Zhang, and X. Feng, “Natural depletion of histone H1 in sex cells causes DNA demethylation, heterochromatin decondensation and transposon activation,” eLife, vol. 8. eLife Sciences Publications, Ltd, 2019. ista: He S, Vickers M, Zhang J, Feng X. 2019. Natural depletion of histone H1 in sex cells causes DNA demethylation, heterochromatin decondensation and transposon activation. eLife. 8, 42530. mla: He, Shengbo, et al. “Natural Depletion of Histone H1 in Sex Cells Causes DNA Demethylation, Heterochromatin Decondensation and Transposon Activation.” ELife, vol. 8, 42530, eLife Sciences Publications, Ltd, 2019, doi:10.7554/elife.42530. short: S. He, M. Vickers, J. Zhang, X. Feng, ELife 8 (2019). date_created: 2023-01-16T09:17:21Z date_published: 2019-05-28T00:00:00Z date_updated: 2023-05-08T10:54:12Z day: '28' ddc: - '580' department: - _id: XiFe doi: 10.7554/elife.42530 extern: '1' external_id: unknown: - '31135340' file: - access_level: open_access checksum: ea6b89c20d59e5eb3646916fe5d568ad content_type: application/pdf creator: alisjak date_created: 2023-02-07T09:42:46Z date_updated: 2023-02-07T09:42:46Z file_id: '12525' file_name: 2019_elife_He.pdf file_size: 2493837 relation: main_file success: 1 file_date_updated: 2023-02-07T09:42:46Z has_accepted_license: '1' intvolume: ' 8' keyword: - General Immunology and Microbiology - General Biochemistry - Genetics and Molecular Biology - General Medicine - General Neuroscience language: - iso: eng license: https://creativecommons.org/licenses/by/4.0/ main_file_link: - open_access: '1' url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594752/ month: '05' oa: 1 oa_version: Published Version publication: eLife publication_identifier: issn: - 2050-084X publication_status: published publisher: eLife Sciences Publications, Ltd quality_controlled: '1' scopus_import: '1' status: public title: Natural depletion of histone H1 in sex cells causes DNA demethylation, heterochromatin decondensation and transposon activation tmp: image: /images/cc_by.png legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0) short: CC BY (4.0) type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 8 year: '2019' ... --- _id: '12190' abstract: - lang: eng text: Meiotic crossover frequency varies within genomes, which influences genetic diversity and adaptation. In turn, genetic variation within populations can act to modify crossover frequency in cis and trans. To identify genetic variation that controls meiotic crossover frequency, we screened Arabidopsis accessions using fluorescent recombination reporters. We mapped a genetic modifier of crossover frequency in Col × Bur populations of Arabidopsis to a premature stop codon within TBP-ASSOCIATED FACTOR 4b (TAF4b), which encodes a subunit of the RNA polymerase II general transcription factor TFIID. The Arabidopsis taf4b mutation is a rare variant found in the British Isles, originating in South-West Ireland. Using genetics, genomics, and immunocytology, we demonstrate a genome-wide decrease in taf4b crossovers, with strongest reduction in the sub-telomeric regions. Using RNA sequencing (RNA-seq) from purified meiocytes, we show that TAF4b expression is meiocyte enriched, whereas its paralog TAF4 is broadly expressed. Consistent with the role of TFIID in promoting gene expression, RNA-seq of wild-type and taf4b meiocytes identified widespread transcriptional changes, including in genes that regulate the meiotic cell cycle and recombination. Therefore, TAF4b duplication is associated with acquisition of meiocyte-specific expression and promotion of germline transcription, which act directly or indirectly to elevate crossovers. This identifies a novel mode of meiotic recombination control via a general transcription factor. acknowledgement: "We thank Gregory Copenhaver (University of North Carolina), Avraham Levy (The Weizmann Institute), and Scott Poethig (University of Pennsylvania) for FTLs; Piotr Ziolkowski for Col-420/Bur seed; Sureshkumar Balasubramanian\r\n(Monash University) for providing British and Irish Arabidopsis accessions; Mathilde Grelon (INRA, Versailles) for providing the MLH1 antibody; and the Gurdon Institute for access to microscopes. This work was supported by a BBSRC DTP studentship (E.J.L.), European Research Area Network for Coordinating Action in Plant Sciences/BBSRC ‘‘DeCOP’’ (BB/M004937/1; C.L.), a BBSRC David Phillips Fellowship (BB/L025043/1; H.G. and X.F.), the European Research Council (CoG ‘‘SynthHotspot,’’ A.J.T., C.L., and I.R.H.; StG ‘‘SexMeth,’’ X.F.), and a Sainsbury Charitable Foundation Studentship (A.R.B.)." article_processing_charge: No article_type: original author: - first_name: Emma J. full_name: Lawrence, Emma J. last_name: Lawrence - first_name: Hongbo full_name: Gao, Hongbo last_name: Gao - first_name: Andrew J. full_name: Tock, Andrew J. last_name: Tock - first_name: Christophe full_name: Lambing, Christophe last_name: Lambing - first_name: Alexander R. full_name: Blackwell, Alexander R. last_name: Blackwell - first_name: Xiaoqi full_name: Feng, Xiaoqi id: e0164712-22ee-11ed-b12a-d80fcdf35958 last_name: Feng orcid: 0000-0002-4008-1234 - first_name: Ian R. full_name: Henderson, Ian R. last_name: Henderson citation: ama: Lawrence EJ, Gao H, Tock AJ, et al. Natural variation in TBP-ASSOCIATED FACTOR 4b controls meiotic crossover and germline transcription in Arabidopsis. Current Biology. 2019;29(16):2676-2686.e3. doi:10.1016/j.cub.2019.06.084 apa: Lawrence, E. J., Gao, H., Tock, A. J., Lambing, C., Blackwell, A. R., Feng, X., & Henderson, I. R. (2019). Natural variation in TBP-ASSOCIATED FACTOR 4b controls meiotic crossover and germline transcription in Arabidopsis. Current Biology. Elsevier BV. https://doi.org/10.1016/j.cub.2019.06.084 chicago: Lawrence, Emma J., Hongbo Gao, Andrew J. Tock, Christophe Lambing, Alexander R. Blackwell, Xiaoqi Feng, and Ian R. Henderson. “Natural Variation in TBP-ASSOCIATED FACTOR 4b Controls Meiotic Crossover and Germline Transcription in Arabidopsis.” Current Biology. Elsevier BV, 2019. https://doi.org/10.1016/j.cub.2019.06.084. ieee: E. J. Lawrence et al., “Natural variation in TBP-ASSOCIATED FACTOR 4b controls meiotic crossover and germline transcription in Arabidopsis,” Current Biology, vol. 29, no. 16. Elsevier BV, p. 2676–2686.e3, 2019. ista: Lawrence EJ, Gao H, Tock AJ, Lambing C, Blackwell AR, Feng X, Henderson IR. 2019. Natural variation in TBP-ASSOCIATED FACTOR 4b controls meiotic crossover and germline transcription in Arabidopsis. Current Biology. 29(16), 2676–2686.e3. mla: Lawrence, Emma J., et al. “Natural Variation in TBP-ASSOCIATED FACTOR 4b Controls Meiotic Crossover and Germline Transcription in Arabidopsis.” Current Biology, vol. 29, no. 16, Elsevier BV, 2019, p. 2676–2686.e3, doi:10.1016/j.cub.2019.06.084. short: E.J. Lawrence, H. Gao, A.J. Tock, C. Lambing, A.R. Blackwell, X. Feng, I.R. Henderson, Current Biology 29 (2019) 2676–2686.e3. date_created: 2023-01-16T09:16:33Z date_published: 2019-08-19T00:00:00Z date_updated: 2023-05-08T10:54:54Z day: '19' department: - _id: XiFe doi: 10.1016/j.cub.2019.06.084 extern: '1' external_id: pmid: - '31378616' intvolume: ' 29' issue: '16' keyword: - General Agricultural and Biological Sciences - General Biochemistry - Genetics and Molecular Biology language: - iso: eng month: '08' oa_version: None page: 2676-2686.e3 pmid: 1 publication: Current Biology publication_identifier: issn: - 0960-9822 publication_status: published publisher: Elsevier BV quality_controlled: '1' scopus_import: '1' status: public title: Natural variation in TBP-ASSOCIATED FACTOR 4b controls meiotic crossover and germline transcription in Arabidopsis type: journal_article user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87 volume: 29 year: '2019' ... --- _id: '8305' abstract: - lang: eng text: In this paper, we present the first fully asynchronous distributed key generation (ADKG) algorithm as well as the first distributed key generation algorithm that can create keys with a dual (f,2f+1)−threshold that are necessary for scalable consensus (which so far needs a trusted dealer assumption). In order to create a DKG with a dual (f,2f+1)− threshold we first answer in the affirmative the open question posed by Cachin et al. how to create an AVSS protocol with recovery thresholds f+1