Chromatin States and their diverse protein occupancy drive genome organization in S. cerevisiae through heterogeneous Brownian motion
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE105075 | GEO | 2020/10/13
REPOSITORIES: GEO
Similar Datasets
Project description:Chromatin States and their diverse protein occupancy drive genome organization in S. cerevisiae through heterogeneous Brownian motion
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Project description:Our understanding of endocytic pathway dynamics is severely restricted by the diffraction limit of light microscopy. To address this, we implemented a novel technique based on the subdiffractional tracking of internalized molecules (sdTIM). This allowed us to image anti-green fluorescent protein Atto647N-tagged nanobodies trapped in synaptic vesicles (SVs) from live hippocampal nerve terminals expressing vesicle-associated membrane protein 2 (VAMP2)-pHluorin with 36-nm localization precision. Our results showed that, once internalized, VAMP2-pHluorin/Atto647N-tagged nanobodies exhibited a markedly lower mobility than on the plasma membrane, an effect that was reversed upon restimulation in presynapses but not in neighboring axons. Using Bayesian model selection applied to hidden Markov modeling, we found that SVs oscillated between diffusive states or a combination of diffusive and transport states with opposite directionality. Importantly, SVs exhibiting diffusive motion were relatively less likely to switch to the transport motion. These results highlight the potential of the sdTIM technique to provide new insights into the dynamics of endocytic pathways in a wide variety of cellular settings.
| S-EPMC5080683 | biostudies-literature
Project description:DNA methylation at a gene promoter region has the potential to regulate gene transcription. Their patterns are often complex with the region showing multiple allelic patterns in a sample. This complexity is commonly obscured when DNA methylation data is summarised as an average percentage value for each CpG site (or aggregated across CpG sites). The methylation state at adjacent CpG sites is therefore lost when data is summarised this way. Methylation patterns can only be characterised by clonal analysis. Deep sequencing provides the ability to investigate clonal DNA methylation patterns in unprecedented detail and scale, enabling the proper characterisation of the heterogeneity of methylation patterns. However, the sheer amount of sequencing data requires new synoptic approaches to visualise the distribution of allelic patterns. We have developed an analysis and visualisation software tool "Methpat", that extracts and displays clonal DNA methylation patterns from massively parallel sequencing data aligned using Bismark. We have performed multiplex bisulfite amplicon sequencing on a range of CpG island targets across a panel of human cell lines and primary tissues. Using Methpat, we demonstrate clonal diversity of epialleles analysed at specific gene promoter regions. We also describe the existence of DNA methylation within the mitochondrial genome.
2015-11-23 | GSE67856 | GEO
Project description:Studies of membrane protein structure and function often rely on reconstituting the protein into lipid bilayers through the formation of liposomes. Many measurements conducted in proteoliposomes, e.g. transport rates, single-molecule dynamics, monomer-oligomer equilibrium, require some understanding of the occupancy statistics of the liposome population for correct interpretation of the results. In homogenous liposomes, this is easy to calculate as the act of protein incorporation can be described by the Poisson distribution. However, in reality, liposomes are heterogeneous, which alters the statistics of occupancy in several ways. Here, we determine the liposome occupancy distribution for membrane protein reconstitution while considering liposome size heterogeneity. We calculate the protein occupancy for a homogenous population of liposomes with radius r = 200 nm, representing an idealization of vesicles extruded through 400 nm pores and compare it to the right-skewed distribution of 400 nm 2:1 POPE:POPG vesicles. As is the case for E. coli polar lipids, this synthetic composition yields a sub-population of small liposomes, 25-30 nm in radius with a long tail of larger vesicles. Previously published microscopy data of the co-localization of the CLC-ec1 Cl-/H+ transporter with liposomes, and vesicle occupancy measurements using functional transport assays, shows agreement with the heterogeneous 2:1 POPE:POPG population. Next, distributions of 100 nm and 30 nm extruded 2:1 POPE:POPG liposomes are measured by cryo-electron microscopy, demonstrating that extrusion through smaller pores does not shift the peak, but reduces polydispersity arising from large liposomes. Single-molecule photobleaching analysis of CLC-ec1-Cy5 shows the 30 nm extruded population increases the 'Poisson-dilution' range, reducing the probability of vesicles with more than one protein at higher protein/lipid densities. These results demonstrate that the occupancy distributions of membrane proteins into vesicles can be accurately predicted in heterogeneous populations with experimental knowledge of the liposome size distribution. This article is part of a Special Issue entitled: Molecular biophysics of membranes and membrane proteins.
| S-EPMC6899186 | biostudies-literature
Project description:We performed CITE-seq (10x Genomics-based) to profile and compare the transcriptomes and cell surface expression of immune epitopes in the brains of anti-VISTA+anti-PD-L1 treated (Dual TX) and control, non-treated mice. We sequenced a total of eight samples (4 control, 4 dual TX). We created an antibody pool consisting of 35 different antibodies and stained each sample individually with this antibody pool. Then, we stained each sample with it's own unique hashing antibody so that we could subsequently pool the samples for loading onto the 10x Chromium and later prepare one library consisting of all sight samples and finally separate each sample in silico by it's unique hashing antibody. The samples are as follows: (1) HTO1: Control/Non-treated (2) HTO2: Control/Non-treated ; (3) HTO3: Control/Non-treated ; (4) Control/Non-treated ; (5) HTO5: Dual TX; (6) Dual TX; (7) HTO7: Dual TX; (8) HTO8: Dual TX. The following sample comparisons were made: HTO1 - HTO4 were compared to HTO5 - HTO8.
2020-10-29 | GSE158579 | GEO
Project description:Chromosome organization and dynamics are involved in regulating many fundamental processes such as gene transcription and DNA repair. Experiments unveiled that chromatin motion is highly heterogeneous inside cell nuclei, ranging from a liquid-like, mobile state to a gel-like, rigid regime. Using polymer modeling, we investigate how these different physical states and dynamical heterogeneities may emerge from the same structural mechanisms. We found that the formation of topologically associating domains (TADs) is a key driver of chromatin motion heterogeneity. In particular, we showed that the local degree of compaction of the TAD regulates the transition from a weakly compact, fluid state of chromatin to a more compact, gel state exhibiting anomalous diffusion and coherent motion. Our work provides a comprehensive study of chromosome dynamics and a unified view of chromatin motion enabling interpretation of the wide variety of dynamical behaviors observed experimentally across different biological conditions, suggesting that the "liquid" or "solid" state of chromatin are in fact two sides of the same coin.
| S-EPMC8744683 | biostudies-literature
Project description:DNA methylation at a gene promoter region has the potential to regulate gene transcription. Their patterns are often complex with the region showing multiple allelic patterns in a sample. This complexity is commonly obscured when DNA methylation data is summarised as an average percentage value for each CpG site (or aggregated across CpG sites). The methylation state at adjacent CpG sites is therefore lost when data is summarised this way. Methylation patterns can only be characterised by clonal analysis. Deep sequencing provides the ability to investigate clonal DNA methylation patterns in unprecedented detail and scale, enabling the proper characterisation of the heterogeneity of methylation patterns. However, the sheer amount of sequencing data requires new synoptic approaches to visualise the distribution of allelic patterns. We have developed an analysis and visualisation software tool "Methpat", that extracts and displays clonal DNA methylation patterns from massively parallel sequencing data aligned using Bismark. We have performed multiplex bisulfite amplicon sequencing on a range of CpG island targets across a panel of human cell lines and primary tissues. Using Methpat, we demonstrate clonal diversity of epialleles analysed at specific gene promoter regions. We also describe the existence of DNA methylation within the mitochondrial genome. Multiplex bisulfite PCR and Next Generation sequencing of 35 samples
2015-11-23 | E-GEOD-67856 | biostudies-arrayexpress
Project description:We performed CITE-seq (10x Genomics-based) to profile and compare the transcriptomes and cell surface expression of immune epitopes in the brains of Cx3cr1+/- and Cx3cr1-/- mice during homeostasis or brain metastasis. We sequenced a total of eight different samples. We created an antibody pool consisting of 35 different antibodies and stained each sample individually with this antibody pool. Then, we stained each sample with it's own unique hashing antibody so that we could subsequently pool the samples for loading onto the 10x Chromium and later prepare one library consisting of all sight samples and finally separate each sample in silico by it's unique hashing antibody. The samples are as follows: (1) HTO1: brain of naïve Cx3cr1+/- mouse; (2) HTO2: brain of naïve Cx3cr1+/- mouse; (3) HTO3: brain of metastasis-burdened Cx3cr1+/- mouse; (4) HTO4: brain of metastasis-burdened Cx3cr1+/- mouse; (5) HTO5: brain of naïve Cx3cr1-/- mouse; (6) HTO6: brain of naïve Cx3cr1-/- mouse; (7) HTO7: brain of metastasis-burdened Cx3cr1-/- mouse; (8) HTO8: brain of metastasis-burdened Cx3cr1-/- mouse. The following sample comparisons were made: HTO1 and HTO2 versus HTO5 and HTO6; HTO3 and HTO4 versus HTO7 and HTO8.
2020-10-29 | GSE139970 | GEO
Project description:We performed CITE-seq (10x Genomics-based) to profile and compare the transcriptomes and cell surface expression of immune epitopes in the brains and blood of different transgenic mice (Cx3cr1+/-; Cx3cr1-/-; CCR2+/-; CCR2-/-) during homeostasis or brain metastasis. We sequenced a total of eight different samples. We created an antibody pool consisting of 35 different antibodies and stained each sample individually with this antibody pool. Then, we stained each sample with it's own unique hashing antibody so that we could subsequently pool the samples for loading onto the 10x Chromium and later prepare one library consisting of all sight samples and finally separate each sample in silico by it's unique hashing antibody. The samples are as follows: (1) HTO1: brain of naïve CCR2+/- mouse; (2) HTO2: brain of naïve CCR2+/- mouse; (3) HTO3: brain of naïve CCR2-/- mouse; (4) HTO4: brain of naive CCR2-/-; (5) HTO5: blood of naïve Cx3cr1+/- mouse; (6) HTO6: blood of metastasis-burdened Cx3cr1+/- mouse; (7) HTO7: blood of naïve Cx3cr1-/- mouse; (8) HTO8: blood of metastasis-burdened Cx3cr1-/- mouse.The following sample comparisons were made: HTO1 and HTO2 versus HTO3 and HTO4; HTO5 versus HTO7; HTO6 versus HTO8.
2020-10-29 | GSE139969 | GEO
Project description:In multicellular organisms, cell-adhesion molecules connect cells into tissues and mediate intercellular signaling between these cells. In vertebrate brains, synaptic cell-adhesion molecules (SAMs) guide the formation, specification, and plasticity of synapses. Some SAMs, when overexpressed in cultured neurons or in heterologous cells co-cultured with neurons, drive formation of synaptic specializations onto the overexpressing cells. However, genetic deletion of the same SAMs from neurons often has no effect on synapse numbers, but frequently severely impairs synaptic transmission, suggesting that most SAMs control the function and plasticity of synapses (i.e., organize synapses) instead of driving their initial establishment (i.e., make synapses). Since few SAMs were identified that mediate initial synapse formation, it is difficult to develop methods that enable experimental control of synaptic connections by targeted expression of these SAMs. To overcome this difficulty, we engineered novel SAMs from bacterial proteins with no eukaryotic homologues that drive synapse formation. We named these engineered adhesion proteins "Barnoligin" and "Starexin" because they were assembled from parts of Barnase and Neuroligin-1 or of Barstar and Neurexin3β, respectively. Barnoligin and Starexin robustly induce the formation of synaptic specializations in a specific and directional manner in cultured neurons. Synapse formation by Barnoligin and Starexin requires both their extracellular Barnase- and Barstar-derived interaction domains and their Neuroligin- and Neurexin-derived intracellular signaling domains. Our findings support a model of synapse formation whereby trans-synaptic interactions by SAMs drive synapse organization via adhesive interactions that activate signaling cascades.
| S-EPMC9934208 | biostudies-literature