A replisome-associated parental histone H3-H4 tetramer chaperone required for faithful epigenetic inheritance
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1121313 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Faithful transfer of parental histones to newly replicated daughter DNA strands is critical for inheritance of epigenetic states. Although replication proteins that facilitate parental histone transfer have been identified, how intact histone H3-H4 tetramers travel relatively large distances from the front to the back of the replication fork remains unknown. Here, we use AlphaFold-Multimer structural predictions combined with biochemical and genetic approaches to identify the Mrc1/CLASPIN subunit of the replisome as a histone chaperone. Mrc1 contains a conserved histone binding domain that forms a brace around the H3-H4 tetramer mimicking nucleosomal DNA and H2A-H2B histones, is required for heterochromatin inheritance, and promotes parental histone recycling during replication. We further identify binding sites for the FACT histone chaperone in Swi1/TIMELESS and DNA polymerase α that are required for heterochromatin inheritance. We propose that Mrc1, in concert with FACT acting as a mobile co-chaperone, coordinates the distribution of parental histones to newly replicated DNA.
2024-07-29 | GSE269383 | GEO
Project description:High Throughput pMHC-I Tetramer Library Production Using Chaperone Mediated Peptide Exchange
| PRJNA612056 | ENA
Project description:Peptide exchange technologies are essential for the generation of pMHC-multimer libraries for probing diverse, polyclonal TCR repertoires in various settings. Here we report, using the molecular chaperone TAPBPR, a robust method for the capture of stable, empty MHC-I molecules, which can be readily tetramerized and loaded with peptides of choice in a high-throughput manner. Alternatively, catalytic amounts of TAPBPR can be used to exchange ‘goldilocks’ peptides with high-affinity peptides of interest in an overnight reaction. Using the same system, we describe high-throughput assays to validate binding of multiple candidate peptides on the empty MHCI groove. Combined with tetramer-barcoding via a multi-modal cellular indexing technology, ECCITE-seq, our approach allows a combined analysis of TCR repertoires and other T-cell transcription profiles together with their cognate pMHC-I specificities in a single experiment.
2020-03-12 | GSE146826 | GEO
Project description:Replication forks temporarily or terminally pause at hundreds of hard-to-replicate regions around the genome. A conserved pair of budding yeast replisome components Tof1-Csm3 (fission yeast Swi1-Swi3 and human TIMELESS-TIPIN) acts as a ‘molecular brake’ and promotes fork slowdown at proteinaceous replication fork barriers (RFBs), while the accessory helicase Rrm3 assists the replisome in removing protein obstacles. Here we show that Tof1-Csm3 complex promotes fork pausing independently of Rrm3 helicase by recruiting topoisomerase I (Top1) to the replisome. Topoisomerase II (Top2) partially compensates for the pausing decrease in cells when Top1 is lost from the replisome. The C-terminus of Tof1 is specifically required for Top1 recruitment to the replisome and fork pausing but not for DNA replication checkpoint (DRC) activation. We propose that forks pause at proteinaceous RFBs through a ‘sTOP’ mechanism (‘slowing down with TOPoisomerases I-II’), which we show also contributes to protecting cells from topoisomerase-blocking agents.
2019-11-07 | GSE140034 | GEO
Project description:Cells use specific mechanisms such as histone chaperones to abrogate the inherent barrier that the nucleosome poses to transcribing polymerases. The current model postulates that nucleosomes can be transiently disrupted to accommodate passage of RNA polymerases and that histones H3 and H4 possess their own chaperones dedicated to the recovery of nucleosomes. Here, we determined the crystal structure of the conserved C terminus of human Suppressors of Ty insertions 2 (hSpt2C) chaperone bound to an H3/H4 tetramer. The structural studies demonstrate that hSpt2C is bound to the periphery of the H3/H4 tetramer, mimicking the trajectory of nucleosomal-bound DNA. These structural studies have been complemented with in vitro binding and in vivo functional studies on mutants that disrupt key intermolecular contacts involving two acidic patches and hydrophobic residues on Spt2C. We show that contacts between both human and yeast Spt2C with the H3/H4 tetramer are required for the suppression of H3/H4 exchange as measured by H3K56ac and new H3 deposition. These interactions are also crucial for the inhibition of spurious transcription from within coding regions. Together, our data indicate that Spt2 interacts with the periphery of the H3/H4 tetramer and promotes its recycling in the wake of RNA polymerase.
| S-EPMC4495402 | biostudies-literature
Project description:Single-molecule mapping of replisome progression
| PRJNA798753 | ENA
Project description:We utilized H2-I-Ab tetramers to isolate CD4 T cells from mice to characterize the functional characteristics of ileal intraepithelial T cells and their lymphoid counterparts in the corresponding draining lymph nodes (mLN). Non-CD4 T cells (B220+, CD11b+, CD11c+, F4/80+, CD8a+) were excluded before FACS-sorting of CD45+CD3+CD4+ tetramer-specific T cells discriminated by double-positive staining with dual-labeled tetramer fluorophores. We recovered tetramer+ and tetramer- IELs and mLN T cells, and profiled them by single-cell RNA and TCR sequencing.
2022-09-01 | GSE196426 | GEO
Project description:RNA-seq of SFB-tetramer+ cells
| PRJNA718888 | ENA
Project description:Old Faithful Geyser Water Communities Genome sequencing and assembly
| PRJNA854645 | ENA
Project description:DNA replication during S-phase is accompanied by establishment of sister chromatid cohesion to ensure faithful chromosome segregation. The Eco1 acetyltransferase, helped by factors including Ctf4 and Chl1, concomitantly acetylates the chromosomal cohesin complex to stabilize its cohesive links. Here we show that Ctf4 recruits the Chl1 helicase to the replisome via a conserved interaction motif that Chl1 shares with GINS and polymerase α. We visualize recruitment by EM analysis of a reconstituted Chl1-Ctf4-GINS assembly. The Chl1 helicase facilitates replication fork progression under conditions of nucleotide depletion, however this function does not require Ctf4 interaction. Conversely, Ctf4 interaction, but not helicase activity, is required for Chl1’s role in sister chromatid cohesion. A physical interaction between Chl1 and the cohesin complex during S-phase suggests that Chl1 contacts cohesin to facilitate its acetylation. Our results reveal how Ctf4 forms a replisomal interaction hub that coordinates replication fork progression and sister chromatid cohesion establishment.
2016-04-08 | GSE80007 | GEO