A transcriptomic analysis reveals increased complexity of the alternative splicing landscape by Nsmce1 overexpression in mouse hippocampal neuronal cell
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE113436 | GEO | 2020/01/01
REPOSITORIES: GEO
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Project description:Smc5/6 is essential for genome structural integrity by yet unknown mechanisms. Here we find that Smc5/6 co-localizes with the DNA crossed-strand processing complex Sgs1-Top3-Rmi1 (STR) at genomic regions known as natural pausing sites (NPSs) where it facilitates Top3 retention. Individual depletions of STR subunits and Smc5/6 cause similar accumulation of joint molecules (JMs) composed of reversed forks, double Holliday Junctions and hemicatenanes, indicative of Smc5/6 regulating Sgs1 and Top3 DNA processing activities. We isolate an intra-allelic suppressor of smc6-56 proficient in Top3 retention but affected in pathways that act complementarily with Sgs1 and Top3 to resolve JMs arising at replication termination. Upon replication stress, the smc6-56 suppressor requires STR and Mus81-Mms4 functions for recovery, but not Srs2 and Mph1 helicases that prevent maturation of recombination intermediates. Thus, Smc5/6 functions jointly with Top3 and STR to mediate replication completion and influences the function of other DNA crossed-strand processing enzymes at NPSs.
2021-02-03 | GSE147452 | GEO
Project description:The function of the SMC5-6 complex is less clear, but it has an important role in a variety of different DNA repair processes and in resolving recombination structures. Interestingly mutation at a highly conserved residue (Ser994) in the ATP hydrolysis motif in the SMC6 C-terminal domain, resulted in mice with a mild phenotype.
2013-04-22 | GSE38737 | GEO
Project description:Silencing of nuclear DNA is an essential feature of the innate immune response to invading pathogens. Early in lentiviral infection, unintegrated viral cDNA accumulates in the nucleus, yet remains poorly expressed. In HIV-1-like lentiviruses, the Vpr accessory protein enhances unintegrated viral DNA expression, suggesting Vpr antagonises cellular restriction. We previously showed how Vpr remodels the host proteome, identifying multiple cellular targets. We now screen these using a targeted CRISPR-Cas9 library, identifying SMC5-SMC6 complex localization factor 2 (SLF2) as the Vpr target responsible for silencing unintegrated HIV-1. SLF2 recruits the SMC5/6 complex to unintegrated lentiviruses, and depletion of SLF2, or the SMC5/6 complex, increases viral expression. Using ATAC-seq, we show that Vpr-mediated SLF2 depletion increases chromatin accessibility of unintegrated virus, suggesting the SMC5/6 complex compacts viral chromatin to silence gene expression. This work implicates the SMC5/6 complex in nuclear immunosurveillance of extrachromosomal DNA and defines an evolutionarily conserved antagonism by Vpr.
2021-03-01 | GSE156630 | GEO
Project description:The function of the SMC5-6 complex is less clear, but it has an important role in a variety of different DNA repair processes and in resolving recombination structures. Interestingly mutation at a highly conserved residue (Ser994) in the ATP hydrolysis motif in the SMC6 C-terminal domain, resulted in mice with a mild phenotype. Total RNA obtained from homozygote 4 male mutant mice was compared to 2-4 wild type or 2 heterozygote controls.
2013-04-22 | E-GEOD-38737 | biostudies-arrayexpress
Project description:The human SMC5-SMC6 complex (SMC5/6) is a conserved guardian of genome stability and an emerging component of the antiviral response in animals and plants. In yeast, Smc5/6 is recruited to and loaded on chromatin by the poorly conserved Nse5-Nse6 heterodimer (Nse5/6), which remains largely undefined in humans. Here we report that SIMC1 is an Nse5 orthologue and novel subunit of the human SMC5/6 complex. SIMC1 binds to SLF2, the proposed Nse6 orthologue, forming a stable complex structurally similar to yeast Nse5/6. SIMC1 localizes SMC5/6 to polyomavirus replication centers in a SUMO interaction-dependent manner. Further structure prediction analyses indicate that SLF1, a putative Nse5 counterpart that recruits SMC5/6 to DNA lesions, interacts with SLF2 in a very similar manner as SIMC1. Consistently, SIMC1 and SLF1 form mutually exclusive complexes with SLF2. Thus, both SIMC1 and SLF1 act as orthologues of yeast Nse5 to independently direct the functions of SMC5/6.
2022-11-29 | PXD033923 | Pride
Project description:During chromosome duplication the parental DNA molecule becomes over-wound, or positively supercoiled, in the region ahead of the advancing replication fork. To allow fork progression this superhelical tension has to be removed by topoisomerases, which operate by introducing transient DNA breaks. Positive supercoiling can also be diminished if the advancing fork rotates along the DNA helix, but then sister chromatid intertwinings form in its wake. Despite these insights it remains largely unknown how replicationinduced superhelical stress is dealt with on linear, eukaryotic chromosomes. Here we show that this stress increases with the length of budding yeast chromosomes. This opens for the possibility that superhelical tension is handled on a chromosome scale and not only within topologically closed chromosomal domains as the current view predicts. We found that inhibition of type I topoisomerases leads to a late replication delay of longer, but not shorter chromosomes. This phenotype is also displayed by cells expressing mutated versions of the cohesin- and condensin–related Smc5/6 complex. The chromosomal association of the Smc5/6 complex is shown to increase in response to chromosome lengthening, chromosome circularization, or inactivation of Topoisomerase 2, all having the potential to increase the number of sister chromatid intertwinings 3. Furthermore, non-functional Smc6 reduces the accumulation of intertwined sister plasmids after one round of replication in the absence of Topoisomerase 2 function. Our results demonstrate that the length of a chromosome influences the need of superhelical tension release in Saccharomyces cerevisiae, and allow us to propose a model where the Smc5/6 complex facilitates fork rotation by sequestering nascent chromatid intertwinings which form behind the replication machinery. Smc6、Nse4, and Scc2 profiles with or without topological tension was analyzed (in top2 mutant, cells with circular chromosome, and fragmented chromosome) . 17 ChIP samples and corresponding WCE fractions have been analyzed.
2011-02-28 | E-GEOD-26263 | biostudies-arrayexpress
Project description:MicroRNAs are non-coding RNAs that act to downregulate the expression of target genes by translational repression and degradation of messenger RNA molecules. Individual microRNAs have the ability to specifically target a wide array of gene transcripts, therefore allowing each microRNA to play key roles in multiple biological pathways. miR-324 is a microRNA predicted to target thousands of RNA transcripts and is expressed far more highly in the brain than in any other tissue, suggesting that it may play a role in one or multiple neurological pathways. Here we present data from the first global miR-324-null mice, in which increased excitability and interictal discharges were identified in vitro in the hippocampus. RNA sequencing was used to identify differentially expressed genes in miR-324-null mice which may contribute to this increased hippocampal excitability, and 3’UTR luciferase assays revealed that some of these genes are novel direct targets of miR-324. Characterisation of microRNAs that produce an effect on neurological activity, such as miR-324, and identification of the pathways they regulate will allow a better understanding of the processes involved in normal neurological function and in turn may present novel pharmaceutical targets in treating neurological disease.
2020-09-23 | GSE158337 | GEO
Project description:BackgroundTMEM16A (Anoctamin 1; ANO1) is an eight transmembrane protein that functions as a calcium-activated chloride channel. TMEM16A in human exhibits alternatively spliced exons (6b, 13 and 15), which confer important roles in the regulation of channel function. Mouse Tmem16a is reported to consist of 25 exons that code for a 956 amino acid protein. In this study our aim was to provide details of mouse Tmem16a genomic structure and to investigate if Tmem16a transcript undergoes alternative splicing to generate channel diversity.ResultsWe identified Tmem16a transcript variants consisting of alternative exons 6b, 10, 13, 14, 15 and 18. Our findings indicate that many of these exons are expressed in various combinations and that these splicing events are mostly conserved between mouse and human. In addition, we confirmed the expression of these exon variants in other mouse tissues. Additional splicing events were identified including a novel conserved exon 13b, tandem splice sites of exon 1 and 21 and two intron retention events.ConclusionOur results suggest that Tmem16a gene is significantly more complex than previously described. The complexity is especially evident in the region spanning exons 6 through 16 where a number of the alternative splicing events are thought to affect calcium sensitivity, voltage dependence and the kinetics of activation and deactivation of this calcium-activated chloride channel. The identification of multiple Tmem16a splice variants suggests that alternative splicing is an exquisite mechanism that operates to diversify TMEM16A channel function in both physiological and pathophysiological conditions.
| S-EPMC3170211 | biostudies-literature
Project description:The SMC protein complexes safeguard genomic integrity through their functions in chromosome segregation and repair. The chromosomal localization of the budding yeast Smc5/6 complex here determined reveals that the complex works specifically on the duplicated genome in differently regulated pathways. One controls the association to centromeres and chromosome arms in unchallenged cells, the second regulates the association to DNA breaks, and the third directs the complex to the chromosome arm that harbors the ribosomal DNA arrays. The chromosomal interaction pattern predicts a function that becomes more important with increasing chromosome length, and that the complex's role in unchallenged cells is independent of DNA damage. Additionally, localization of Smc6 to collapsed replication forks indicates an involvement in their rescue. Altogether this shows that the complex maintains genomic integrity in multiple ways, and evidence is presented that the Smc5/6 complex is needed during replication to prevent the accumulation of branched chromosome structures. Keywords: ChIP-chip analysis ⢠The goal of the experiment - Chromosomal association of the Smc5/6 complex reveals that it functions in differently regulated pathways. ⢠Keywords, for example, time course, cell type comparison, array CGH (the use of MGED ontology terms is recommended). Cell cycle, Double Strand Break Induction, time course after break induction, Saccharomyces cerevisiae, Chromosome VI array, Whole Genome Tiling Array, Smc5, Smc6, Nse1, Nse4, Nse5, Scc1, Scc2, Mre11, Rad53 ⢠Experimental factors Distribution of the Smc5/6 complex in the cell cycle, distribution of Smc5/6 complex before and after induction of a DNA double strand break on chromosome VI in G2/metaphase cells, distribution of Smc6 in the absence of functional Scc2, Mre11 or Rad53, distribution of Smc6 at collapsed replication forks, and distribution of Cohesin subunit Scc1 in G2/metaphase. Distribution was analyzed on Chromosome VI and/or whole genome arrays. Cells were grown in rich yeast cell extract media. All experiments were performed in cells with the same genetic background (Saccharomyces cerevisiae W303; ade2-1, trp1-1, can1-100, leu2-3, 112, his3-11, 15, ura3 RAD5) ⢠Experimental design ChIP analysis: In all cases, hybridization data for ChIP fraction was compared with that of SUP (supernatant) fraction. Cerevisiae chromosome VI array or Whole genome arrays were used. Total number of hybridization was 69. All description about hybridized samples is attached as the separate sheet. ⢠Quality control steps taken Duplication, confirmation using different tags, different subunits of the same complex, and time course after double-strand break induction. Checking of the ChIP fraction by Western blotting. Mock hybridisation of samples immunoprecipitated from cells containing no tag recognized by antibody used. ⢠Links to the publication, any supplemental websites or database accession numbers. http://tilingarray.bio.titech.ac.jp/smc56dsb Samples used, extract preparation and labelling: ⢠The origin of each biological sample Saccharomyces cerevisiae W303 (ade2-1, trp1-1, can1-100, leu2-3, 112, his3-11, 15, ura3 RAD5). ⢠Manipulation of biological samples and protocols used Strains containing flag-tagged versions of Smc6, Smc5, Nse1, Nse4, or Nse5 proteins were used. For synchronization in G1, alpha factor was added (Zymo research and Innovagen AB) at 3 µg/ml final concentrations to logarithmically growing cells, and G1 arrest was obtained at indicated temperatures for 2.5 h. For S-phase arrest, cells were grown to log phase and arrested in G1 with alpha factor for 2 h, and then incubated in the presence of 200 mM hydroxyurea (HU) (Sigma) for 30 min. Cells were then washed twice with rich medium containing 100µg/ml pronase (Calbiochem). Finally cells were resuspended in medium containing HU and pronase, and growth continued for indicated time periods. G2/M arrest was achieved 2.5 h after addition of benomyl (Sigma, 80µg/ml), to logarithmically growing cells. G1, S and G2/M arrests were checked microscopically and by FACS. DSBs were induced by activation of the HO endonuclease from the GAL1-10-promoter by addition of 2% galactose to cell cultures initially grown in 2% raffinose. ⢠Technical protocols for preparing the hybridization extract Extract preparation was processed following the Shirahige lab protocol (http://chromosomedynamics.bio.titech.ac.jp ). 5x108 cells were disrupted using Multi-Beads Shocker (MB400U, YASUI KIKAI, Osaka). Whole cell extract was sonicated to obtain 400-600 bp genomic DNA fragments. Anti-Flag monoclonal antibody M2 (Sigma-Aldrich Co., St Louis, MO) coupled to Dynabeads (Dynal, protein A Dynabeads) were used for chromatin immunoprecipitation. The immunprecipates were eluted and incubated over night at 65ºC to reverse the cross-link. Immunoprecipitated genomic DNA was incubated with proteinase K, extracted 2 times with phenol/chloroform/isoamylalcohol, precipitated, resuspended in TE and incubated with RnaseA. The DNA was then purified using the Qiagen PCR purification kit, and concentrated by ethanol precipitation. The DNA was amplified by PCR after random priming. 10 ug of amplified DNA was digested with Dnase I to a mean size of 100 bp. After Dnase I inactivation at 95ºC. DNA fragments were end-labeled by addition of 25 U of Terminal Transferase and 1 nmol Biotin-N6ddATP (NEN) for 1 hour at 37ºC as previously described by Winzeler et al. (Science. 281, 1194-1197, 1998). The entire sample was used for hybridization. ⢠Hybridization procedures and parameters: Hybridization, blocking and washing were carried out as previously described (http://chromosomedynamics.bio.titech.ac.jp). Each sample was hybridized to the array in 150 ul containing 6xSSPE; 0.005% TritonX-100; 15 ug fragmented denatured salmon sperm DNA (Gibco-BRL); 1 nmole 3'biotin labelled control oligonucleotide (oligo B2, Affymetrix). Samples were denatured at 100ºC for 10 minutes, and then put on ice before being hybridized for 16 hours at 42ºC in a hybridization oven (GeneChip Hybridization Oven 640, Affymetrix). Washing and scanning protocol provided by Affymetrix was performed automatically on a fluidics station (GeneChip fluidics station 450, Affymetrix). ⢠Measurement data and specifications: S. cerevisiae arrays were scanned using the Genechip Scanner3000 7G following the library array description. All the cel files data and processed data files can be downloaded from GEO database or from our Web sites. The primary analysis of tiling chip data was performed following exactly the statistical algorithm used for Affymetrix GeneChip Operating Software (GCOS). The detailed information for the algorithm used can be downloaded from the Affymetrix web site at http://www.affymetrix.com/support/technical/technotes/statistical_reference_guide.pdf. The analysis is available from K.S. on request. For the ChrVI array, one unit for analysis (locus) was set to 300bp and for whole genome arrays to 100bp. Fold change value, change p-value, and detection p-value for each locus were obtained by primary analysis. For the discrimination of positive and negative signals for the binding, we used three criteria as follows. First, the reliability of the signal strength was judged by detection p-value of each locus (p-value<=0.01 for chromosome VI and pvalue?0.0025 for whole genome array). Secondly, reliability of binding ratio was judged by change p-value (p-value<=0.01 for chromosome VI and p-value<=0.0025 for whole genome array). Thirdly, clusters consisting of at least 500bp contiguous loci that satisfied the above two criteria were selected, because it is known that a single site of protein-DNA interaction resulted in immuno-precipitation of DNA fragments that hybridized not only to the locus of the actual binding site but also to its neighbors. Under these conditions both types of arrays give essentially the same results for the binding profile. Repeated sequences were masked out and not included in the calculation of protein binding profile. The correlation coefficient of Smc6 binding profiles in G2/M from two independent experiments was 0.955, showing that the whole genome ChIP on chip data was reproducible. For comparison of the localization of Smc6 in different experiments and that of Smc6 and Scc1 on whole genome maps, peaks with signal to log ratio higher than 0.6 were chosen, and peaks which were distributed within a 5kb region was recognized as one peak. In the analysis of the number of Smc6 localization sites on each chromosome a 40 kb region spanning all centromeres were excluded. This region in addition to that downstream the rDNA repeats was also excluded from the analysis when comparing Smc6 localization in wild type, scc2-4 and scc1-73 cells. ⢠Array Design: General array design: in situ synthesized arrays by Affymetrix Chromosome VI S.cerevisiae: rikDACF, P/N# 510636 Whole Genome Array S.cerevisiae: S.cerevisiae Tiling1.0F Arrays, Part#520286 and Part#520280
2010-06-11 | E-GEOD-4808 | biostudies-arrayexpress
Project description:The SMC protein complexes safeguard genomic integrity through their functions in chromosome segregation and repair. The chromosomal localization of the budding yeast Smc5/6 complex here determined reveals that the complex works specifically on the duplicated genome in differently regulated pathways. One controls the association to centromeres and chromosome arms in unchallenged cells, the second regulates the association to DNA breaks, and the third directs the complex to the chromosome arm that harbors the ribosomal DNA arrays. The chromosomal interaction pattern predicts a function that becomes more important with increasing chromosome length, and that the complex's role in unchallenged cells is independent of DNA damage. Additionally, localization of Smc6 to collapsed replication forks indicates an involvement in their rescue. Altogether this shows that the complex maintains genomic integrity in multiple ways, and evidence is presented that the Smc5/6 complex is needed during replication to prevent the accumulation of branched chromosome structures. Keywords: ChIP-chip analysis
2006-06-23 | GSE4808 | GEO