Project description:Aberrant DNA methylation (DNAm) was first linked to cancer over 25 years ago. Since then, many studies have associated hypermethylation of tumour suppressor genes and hypomethylation of oncogenes to the tumourigenic process. However, most of these studies have been limited to the analysis of promoters and CpG islands (CGIs). Recently, new technologies for whole-genome DNAm (methylome) analysis have been developed, enabling unbiased analysis of cancer methylomes. Using MeDIP-seq, we report a sequencing-based comparative methylome analysis of malignant peripheral nerve sheath tumours (MPNST), benign Neurofibromas and normal Schwann cells. Analysis of these methylomes revealed a complex landscape of DNAm alterations. Contrary to the current dogma, significant global hypomethylation was not observed in the MPNST methylome. However, a highly significant (P<10-100) directional difference in DNAm was found in satellite repeats, suggesting these repeats to be the main target for hypomethylation in MPNST. Comparative analysis of the MPNST and Schwann cell methylomes identified 101,466 cancer-associated differentially methylated regions (cDMRs). Analysis showed these cDMRs to be significantly enriched for two satellite repeat types (SATR1 and ARLM-NM-1) and suggests an association between aberrant DNAm of these sequences and transition from healthy cells to malignant disease. Significant enrichment of hypermethylated cDMRs in CGI shores (P<10-60), non-CGI-associated promoters (P<10-4) and hypomethylated cDMRs in SINE repeats (P<10-100) was also identified. Integration of DNAm and gene expression data showed that the expression pattern of genes associated with CGI shore cDMRs was able to discriminate between disease phenotypes. This study establishes MeDIP-seq as an effective method to analyse cancer methylomes. Examination of methylation profiles in malignant, benign and normal tissue
Project description:This SuperSeries is composed of the following subset Series: GSE13863: Repressive and active histone methylation mark distinct promoters in human and mouse spermatozoa (Nimblegen) GSE19889: Repressive and active histone methylation mark distinct promoters in human and mouse spermatozoa (Illumina) Refer to individual Series
Project description:Small noncoding RNAs (sncRNA) are becoming recognized for their participation in a diverse range of cellular functions. In this study, their global characterization in human spermatozoa from donors with proven fertility was undertaken. Reads were analyzed in two classes, those mapping to unique locations and those that could be aligned to up to 10 genomic locations. All libraries showed comparable distribution of reads between intergenic, intronic and exonic genomic regions. Analysis of the sequences revealed the presence of multiple small RNA classes. The miRNAs retained in spermatozoa were found to be associated with promoter regions, suggestive of a role at the transcriptional level. Piwi-interacting sncRNAs as well as repeat-associated small RNAs were identified for the first time in mature spermatozoa from a mammalian species. Human spermatozoa retain a multifaceted population of small non-coding RNAs. Their presence is consistent with the view that they may function to stabilize the genome as part of the confrontation and consolidation of the genomes at fertilization. Examination of sperm samples from 3 individuals, sequenced individually
Project description:Proteomic investigations of spermatozoa provide practical tools for distinguishing normal, functional spermatozoa from abnormal spermatozoa. Indeed, two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry (MS) applies high-throughput industrial applications to identify sperm-specific proteins indicative of chemical exposure. As such, a direct comparison of protein expression profiles between control and exposed cells returned a set of protein markers. Because mature mammalian spermatozoa are virtually incapable of protein synthesis, the predicted protein biomarkers in spermatozoa offer considerable stability for use in clinical application. In the current study, we applied 2-DE coupled with ESI-MS/MS to investigate the modified protein profile in F1 capacitated spermatozoa due to gestational bisphenol-A (BPA) exposure to ascertain whether these proteomic modifications could explain the observed functional alterations in spermatozoa.
Project description:MicroRNAs (miRNAs) are involved in nearly every biological process examined to date. Mounting evidence show that some spermatozoa specific miRNAs play important roles in the regulation of spermatogenesis and germ cells development, but little is known of the exact identity and function of miRNA in sperm cells or their potential involvement in spermatogenesis and germ cells development. Here, we investigated the spermatozoa miRNA profiles using illumina deep sequencing combined with bioinformatic analysis using zebrafish as a model system. Deep sequencing of small RNAs yielded 12 million raw reads from zebrafish spermatozoa. Analysis showed that the noncoding RNA of the spermatozoa included tRNA, rRNA, snRNA, snoRNA and miRNA. By mapping to the zebrafish genome, we identified 400 novel and 204 conserved miRNAs which could be grouped into 104 families, including zebrafish specific families, such as mir-731, mir-724, mir-725, mir-729 and mir-2185. We report the first characterization of the miRNAs profiling in zebrafish spermatozoa. The obtained spermatozoa miRNAs profiling will serve as valuable resources to systematically study spermatogenesis in fish and vertebrate. Examination of small RNA populations in zebrafish spermatozoa
Project description:We report the application of methylated DNA immunoprecipitation followed by next-generation sequencing to trisomy 8 AML. Through a global study and quantifying the methylation signals, we demonstrated a characteristic DNA methylation distribution for trisomy 8 indicating the impact of the hypermethylation of the extrachromosome 8 on suppressing the signals on the rest of the chromosomes. Examination of 3 relapse trisomy 8 AML patients
Project description:We reported RNA profiles of mice spermatozoa, a total of 35,288,825 reads matching 33,039 transcripts, including 27,310 coding transcripts, were obtained. RNA profiles of the spermatozoa of 9-10 weeks adult mice were sequenced by RNA-seq,using Illumina GAIIx.
Project description:In higher eukaryotes, histone methylation is involved in the maintenance of cellular identity during somatic development. During spermatogenesis, Since most nucleosomes are replaced by protamines during spermatogenesis . Iit is therefore unclear whether if histone modifications function in paternal transmission of epigenetic information. Here we show that H3K4 di-methylation (H3K4me2) and H3K27 tri-methylation (H3K27me3), two modifications important for Trithorax and Polycomb-mediated gene regulation, display methylation-specific distributions at regulatory regions in human spermatozoa. H3K4 dimethylation H3K4me2-marksed promoters of genes relevant control gene functions in spermatogenesis and cellular homeostasis suggesting that this mark reflects germline transcription. In contrast, H3K27 trimethylation (H3K27me3) marks promoters of key developmental regulators in sperm like in somatic cells. Promoters of orthologous genes are similarly modified in mouse spermatozoa. Further, particularly genes with extensive H3K27me3 coverage around transcriptional start sites are never expressed during male and female gametogenesis, nor in pre-implantation embryos. These data are compatible with a function for Polycomb in repressing somatic determinants across generations. Importantly, however, we observe only modest selective retention of nucleosomes at regulatory regions in human sperm suggesting that paternal transmission of H3K27me3-encoded epigenetic information may be subjected to variegation. Identification of nucleosome containing regions in 6 human sperm samples
Project description:The series was designed to identify the different methylated single CpGs involved in the pathophysiology of ulcerative colitis. A cohort of n=20 monozygotic twins, discordant for ulcerative colitis was selected. Illumina and Nimblegen platforms were used.