Biology subjects

Vermeulen, M.

Publications and source records attributed to Vermeulen, M..

6 recordsLinked to original sources

bioRxiv2018

The GBAF chromatin remodeling complex binds H3K27ac and mediates enhancer transcription

H3K27ac is associated with regulatory active enhancers, but its exact role in enhancer function remains elusive. Using mass spectrometry-based interaction proteomics, we identified the Super Elongation Complex (SEC) and GBAF, a non-canonical GLTSCR1L- and BRD9-containing SWI/SNF chromatin remodeling complex, to be major interactors of H3K27ac. We systematically characterized the composition of GBAF and the conserved GLTSCR1/1L GiBAF-domain, which we found to be responsible for GBAF complex formation and GLTSCR1L nuclear localization. Inhibition of the bromodomain of BRD9 revealed interaction between GLTSCR1L and H3K27ac to be BRD9-dependent and led to GLTSCR1L dislocation from its preferred binding sites at H3K27ac-associated enhancers. GLTSCR1L disassociation from chromatin resulted in genome-wide downregulation of enhancer transcription while leaving most mRNA expression levels unchanged, except for reduced mRNA levels from loci topologically linked to affected enhancers. Our results indicate that GBAF is an enhancer-associated chromatin remodeler important for transcriptional and regulatory activity of enhancers.\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=142 HEIGHT=200 SRC=\"FIGDIR/small/445148_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (32K):\norg.highwire.dtl.DTLVardef@10c54dborg.highwire.dtl.DTLVardef@9730dforg.highwire.dtl.DTLVardef@9985eorg.highwire.dtl.DTLVardef@1f26844_HPS_FORMAT_FIGEXP M_FIG C_FIG

genomics↗

bioRxiv2018

MTA proteins act redundantly within the NuRD complex to ensure fidelity of ES cell lineage commitment

Multiprotein chromatin remodelling complexes show remarkable conservation of function amongst metazoans, even though components present in invertebrates are often present as multiple paralogous proteins in vertebrate complexes. In some cases these paralogues specify distinct biochemical and/or functional activities in vertebrate cells. Here we set out to define the biochemical and functional diversity encoded by one such group of proteins within the mammalian Nucleosome Remodelling and Deacetylation (NuRD) complex: Mta1, Mta2 and Mta3. We find that, in contrast to what has been described in somatic cells, MTA proteins are not mutually exclusive within ES cell NuRD and, despite subtle differences in chromatin binding and biochemical interactions, serve largely redundant functions. Nevertheless, ES cells lacking all three MTA proteins represent a complete NuRD null and are viable, allowing us to identify a previously undetected function for NuRD in maintaining differentiation trajectory during early stages of lineage commitment.

developmental biology↗

bioRxiv2018

Induction and suppression of NF-κB signalling by a DNA virus of Drosophila

Interactions between the insect immune system and RNA viruses have been best studied in Drosophila, where RNA interference, NF-O_SCPLOWKC_SCPLOWB and JAK-STAT pathways underlie antiviral immunity. In response to these immune mechanisms, insect viruses have convergently evolved suppressors of RNA interference that act by diverse mechanisms to permit viral replication. However, interactions between the insect immune system and DNA viruses have received less attention, primarily because few Drosophila-infecting DNA virus isolates are available. Here, we use a recently-isolated DNA virus of Drosophila melanogaster, Kallithea virus, to probe known antiviral immune responses and virus evasion tactics in the context of DNA virus infection. We find that fly mutants for RNA interference and Immune deficiency (Imd), but not Toll, pathways are more susceptible to Kallithea virus infection. We identify the Kallithea virus-encoded protein gp83 as a potent inhibitor of Toll signalling, strongly suggesting that Toll mediates antiviral responses during Kallithea virus infection, but that it is suppressed by the virus. Further, we find that Kallithea gp83 inhibits Toll signalling either through NF-O_SCPLOWKC_SCPLOWB transcription factor regulation, or transcriptionally. Together, these results provide a broad description of known antiviral pathways in the context of DNA virus infection and identify the first Toll pathway inhibitor in a Drosophila virus, extending the known diversity of insect virus-encoded immune inhibitors.

microbiology↗

bioRxiv2018

Splicing and epigenetic factors jointly regulate epidermal differentiation

Epidermal homeostasis requires a continuous balance between progenitor cell proliferation and loss of differentiated cells from its surface. During this process cells undergo major changes in their transcriptional programs to accommodate new cellular functions. We found that transcriptional and post-transcriptional mechanisms underlying these changes are functionally connected and jointly control genes involved in cell adhesion, a key process in epidermal maintenance. Using siRNA-based perturbation screens, we identified novel DNA/RNA binding regulators of epidermal differentiation. Computational modeling and experimental validation identified functional interactions between the matrin-type 2 zinc-finger protein ZMAT2 and the epigenetic modifiers ING5, SMARCA5, BRD1, UHRF1, BPTF, SMARCC2. ZMAT2 is required to keep cells in an undifferentiated, proliferative state and quantitative proteomics identified ZMAT2 as an interactor of the pre-spliceosome. RNA-Immunoprecipitation and transcriptome-wide RNA splicing analysis showed that ZMAT2 associates with and regulates transcripts involved in cell adhesion in conjuction with ING5. Thus, joint control by post-transcriptional and epigenetic mechanisms is important to maintain epidermal cells in an undifferentiated state.\n\nHighlights- Gene-perturbation screens identify a role for ZMAT2 in the control of human epidermal differentiation.\n- ZMAT2 functionally interacts with known epigenetic regulators of epidermal differentiation.\n- ZMAT2 interacts with the pre-spliceosome and transcripts involved in cell adhesion.\n- ZMAT2 mediated splicing and epigenetic control jointly target an adhesion related transcriptional program in human epidermal stem cells.

systems biology↗

bioRxiv2018

The Tudor protein Veneno assembles the ping-pong amplification complex that produces viral piRNAs in Aedes mosquitoes

TUDOR-domain containing proteins facilitate PIWI interacting (pi)RNA biogenesis in Drosophila melanogaster and other model organisms. In Aedes aegypti mosquitoes, a somatically active piRNA pathway generates piRNAs from viral RNA during acute infection with cytoplasmic RNA viruses. Viral piRNA biogenesis requires ping-pong amplification by the PIWI proteins Ago3 and Piwi5. We hypothesized that Tudor proteins are required for viral piRNA production and performed a knockdown screen targeting all Ae. aegypti Tudor genes. Knockdown of several Tudor genes resulted in reduced viral piRNA levels, with silencing of AAEL012437 having the strongest effect. This protein, which we named Veneno, associates directly with Ago3 in an sDMA-dependent manner and localizes in cytoplasmic foci reminiscent of piRNA processing granules of Drosophila. Veneno-interactome analyses reveal a network of co-factors including the orthologs of the Drosophila piRNA pathway components Vasa and Yb, which in turn interacts directly with Piwi5. We propose that Veneno assembles a multi-protein complex for ping-pong dependent piRNA production from exogenous viral RNA.

microbiology↗

bioRxiv2017

Immuno-Detection by sequencing (ID-seq) enables large-scale high-dimensional phenotyping in cells.

Cell-based small molecule screening is an effective strategy leading to new medicines. Scientists in the pharmaceutical industry as well as in academia have made tremendous progress in developing both large-scale and smaller-scale screening assays. However, an accessible and universal technology for measuring large numbers of molecular and cellular phenotypes in many samples in parallel is not available. Here, we present the Immuno-Detection by sequencing (ID-seq) technology that combines antibody-based protein detection and DNA-sequencing via DNA-tagged antibodies. We used ID-seq to simultaneously measure 84 (phospho-)proteins in hundreds of samples and screen the effects of ~300 kinase inhibitor probes on primary human epidermal stem cells to characterise the role of 225 kinases. Our work highlighted a previously unrecognized downregulation of mTOR signaling during differentiation and uncovered 13 kinases regulating epidermal renewal through distinct mechanisms.

genomics↗