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ABSTRACT:
PROVIDER: PRJNA986150 | ENA |
REPOSITORIES: ENA
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Project description:The biomarker CA125, a peptide epitope located in several tandem repeats of the mucin MUC16, is the gold-standard for monitoring regression and recurrence of high-grade serous ovarian cancer in response to therapy. However, the CA125 epitope along with several structural features of the MUC16 molecule are ill-defined. One central aspect still unresolved is the number of tandem repeats in MUC16 and how many of these contain the CA125 epitope. Studies from the early 2000s assembled short DNA reads to estimate that MUC16 contained 63 repeats. Here, we conduct Nanopore long-read sequencing of MUC16 transcripts from three primary ovarian tumors and established cell lines (OVCAR3, OVCAR5, and Kuramochi) for a more exhaustive and accurate estimation and sequencing of the MUC16 tandem repeats. The consensus sequence derived from these six sources was confirmed by proteomics validation and agrees with recent additions to the NCBI database. We propose a model of MUC16 containing 19—not 63—tandem repeats. Additionally, we predict the structure of the tandem repeat domain using the deep-learning algorithm, AlphaFold. The predicted structure displays an SEA domain and unstructured linker region rich in proline, serine, and threonine residues in all 19 tandem repeats. Our studies now pave the way for a detailed characterization of the CA125 epitope. Sequencing and modeling of the MUC16 tandem repeats along with their glycoproteomic characterization, currently underway in our laboratories, will help identify novel epitopes in the MUC16 molecule that improve on the sensitivity and clinical utility of the current CA125 assay.
2024-05-21 | PXD044117 | Pride
Project description:Tandem repeat sequencing in XLID
| PRJEB21659 | ENA
Project description:In plants, RNA polymerase II (Pol II) transcription of inverted DNA repeats produces hairpin RNAs that are processed by several DICER-LIKE enzymes into siRNAs that are 21-24-nt in length. When targeted to transcriptional regulatory regions, the 24-nt size class can induce RNA-directed DNA methylation (RdDM) and transcriptional gene silencing (TGS). In a forward genetic screen to identify mutants defective in RdDM of a target enhancer leading to TGS of a downstream GFP reporter gene in Arabidopsis thaliana, we recovered a structurally mutated silencer locus, named SM-NM-^T35S, in which the 35S promoter driving transcription of an inverted repeat of target enhancer sequences had been specifically deleted. Although Pol II-dependent, hairpin-derived 21-24-nt siRNAs were no longer generated at the newly created SM-NM-^T35S locus, the GFP reporter gene was nevertheless still partially silenced. Silencing was associated with methylation in a short tandem repeat in the upstream target enhancer and with low levels of 24-nt tandem repeat siRNAs. Introducing an nrpd1 mutation into the SM-NM-^T35S line fully released GFP silencing and eliminated both the tandem repeat methylation and associated 24-nt siRNAs, demonstrating their dependence on Pol IV. Deletion of the 35S promoter thus revealed a Pol IV-dependent pathway of 24-nt siRNA biogenesis that was previously inhibited or masked by the Pol II-dependent pathway in wild-type plants. Both Pol II- and Pol IV-dependent siRNAs accrued predominantly from cytosine (C)-containing segments of the tandem repeat monomer, suggesting that the local base composition influenced siRNA accumulation. Preferential accumulation of siRNAs at C-containing sequences was also observed at an endogenous tandem repeat comprising discrete C-rich and AT-rich sections. Our studies illuminate the potential complexity of siRNA generation at repeat-containing loci and show that Pol IV can act in siRNA biogenesis in the absence of a conventional Pol II promoter. Examination of whole-genome DNA methylation status in transgenic T+S Arabidopsis plant
2013-05-30 | E-GEOD-47453 | biostudies-arrayexpress
Project description:L061 family with idiopathic non-syndromic intellectual disability remained unsolved after targeted screening of ID-related genes, array-CGH and exome sequencing. In order to perform custom tandem repeat screening on the X chromosome by long read single molecule sequencing, X-linkage needed to be confirmed by SNP arrays.
2017-12-01 | E-MTAB-5903 | biostudies-arrayexpress
Project description:Introducing ribosomal tandem repeat barcoding for fungi
| PRJEB26696 | ENA
Project description:Investigate the cooperative action of MUC16 with other defined oncogenic mutations in the metastasis of PC using Muc16–/– mice
2022-10-22 | GSE212777 | GEO
Project description:The present work developed a non-affinity-based chromatographic method to enrich MUC16 from serum. The enriched MUC16 sample was further processed using a Midi Top 14 abundant protein depletion column. Peptides identified using bottom-up proteomics yielded 1–8% coverage of MUC16. Additionally, MUC16 was detected in samples containing less than the clinical cut-off level of CA125 (35 U/mL), suggesting that this strategy of enrichment and bottom-up proteomics can enable analysis of CA125 from serum of individuals with early-stage ovarian cancer and those whose tumors express CA125 (MUC16) at low levels.
2024-10-17 | PXD053289 | Pride
Project description:Purpose. How vitamin A contributes to the maintenance of the wet-surfaced phenotype at the ocular surface is not well understood. We sought to identify vitamin A responsive genes in ocular surface epithelia using gene microarray analysis of cultures of a human conjunctival epithelial cell line (HCjE) grown with all-trans-retinoic acid (RA). The analysis showed that the membrane-associated mucin MUC16 was induced by RA and that secretory phospholipase A2 Group IIA (sPLA2-IIA), the gene most upregulated by RA, was induced earlier. Since eicosanoids, metabolites of arachidonic acid, which is produced by sPLA2 catalysis of membrane phospholipids, have been demonstrated to affect mucin production, we sought to determine if the sPLA2 induction in HCjE cells was associated with RA induction of MUC16. Methods. HCjE cells were cultured with or without RA for 3, 6, 24 and 48 hours. Complementary RNA prepared from RNA of the HCjE cells was hybridized to human gene chips (HG-U133A; Affymetrix) and analyzed using Rosetta Resolver software. Microarray data on mucin expression were validated by real-time PCR. To investigate whether sPLA2 is associated with RA-induced MUC16 upregulation, HCjE cells were incubated with RA and the broad spectrum PLA2 inhibitor, aristolochic acid (ArA) or the specific sPLA2-IIA inhibitor LY315920, followed by analysis of MUC16 mRNA and protein by real-time PCR and Western blot analysis. Results. After RA addition, 28 transcripts were upregulated and 6 downregulated by over 2.0-fold (p < 0.01) at both 3 and 6 hours (early phase). Eighty gene transcripts were upregulated and 45 downregulated at both 24 and 48 hours (late phase). Group IIA sPLA2, significantly upregulated by 24 hours, and MUC16 were the most upregulated RNAs by RA at 48 hours. sPLA2 upregulation by RA was confirmed by Western blot analysis. When HCjE cells were incubated with RA plus ArA or specific inhibitor of sPLA2-IIA, LY315920, the RA-induced MUC16 mRNA was significantly reduced (p < 0.01). Conclusion. The retinoic acid-associated upregulation of membrane-associated mucin MUC16 at late phase appears to be through sPLA2-IIA. Upregulation of this hydrophilic membrane-associated mucin may be one of the important mechanisms by which vitamin A facilitates maintenance of the wet-surfaced phenotype on the ocular surface. Experiment Overall Design: Time course of retinoic acid treatment of human conjunctival epithelial cells: 0 (control), 3, 6, 12, 24, and 48 hours. 2 samples per time point.
2007-12-12 | E-GEOD-2835 | biostudies-arrayexpress