Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Sequence and expression analysis of human chromosome 20 gaps

ABSTRACT: The finished human genome-assemblies comprise several hundred un-sequenced euchromatic gaps, which may be rich in long polypurine/polypyrimidine stretches. Human chromosome 20 currently has three remaining un-sequenced gaps on its q-arm. All three gaps are within gene-dense regions, or overlap loci associated with human disorders, including one gap, which is at DLGAP4. In this study we sequenced, determined the complete sizes and assessed epigenetic landscapes of all three un-sequenced gaps on human chromosome 20 using a methodological approach involving Sanger sequencing, mate-pair paired-end high-throughput sequencing and chromatin and methylation analysis. We found histone H3K27me3 to be distributed across all three gaps in immortalized B-lymphocytes. We found five novel CpG islands in one gap to be highly hypermethylated in genomic DNA from both peripheral blood lymphocytes and human cerebellum. One of these CpG islands was differentially methylated and paternally hypermethylated. Furthermore, computational analyses predicted the presence of structured non-coding RNAs (ncRNAs) in all three chromosome 20 gaps. We verified expression for thirteen candidate ncRNAs, some of which showed tissue-specificity. Four ncRNAs expressed within the gap at DLGAP4 show elevated expression particularly in the human brain. Our data suggests that un-sequenced human genome gaps may comprise functional elements. Mate-pair paired end sequencing using genomic DNA from human translocation carriers having chromosomal rearrangments of chromosomes other than chromosome 20 and chromatin, DNA methylation analysis using human peripheral blood lymphocytes and/or human cerebellum tissue. Analysis done for three remaining human chromosome 20 un-sequenced gap regions.

ORGANISM(S): Homo sapiens

SUBMITTER: Sheroy Minocherhomji

PROVIDER: E-GEOD-35405 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Publications

Sequence and expression analysis of gaps in human chromosome 20.

Minocherhomji Sheroy S Seemann Stefan S Mang Yuan Y El-Schich Zahra Z Bak Mads M Hansen Claus C Papadopoulos Nickolas N Josefsen Knud K Nielsen Henrik H Gorodkin Jan J Tommerup Niels N Silahtaroglu Asli A

Nucleic acids research 20120417 14

The finished human genome-assemblies comprise several hundred un-sequenced euchromatic gaps, which may be rich in long polypurine/polypyrimidine stretches. Human chromosome 20 (chr 20) currently has three unfinished gaps remaining on its q-arm. All three gaps are within gene-dense regions and/or overlap disease-associated loci, including the DLGAP4 locus. In this study, we sequenced ∼ 99% of all three unfinished gaps on human chr 20, determined their complete genomic sizes and assessed epigeneti ...[more]

PMID: 22510267

Similar Datasets

Project description:Dysregulation of the epigenome is a common event in malignancy. However, deciphering the earliest cancer associated epigenetic events remains a challenge. Cancer epigenome studies to date have primarily utilised cancer cell lines or clinical samples, where it is difficult to identify the initial epigenetic lesions from those that occur over time. Here, we analysed the epigenome of normal Human Mammary Epithelial Cells (HMEC) and a matched variant cell population (vHMEC) that has escaped senescence and undergone partial carcinogenic transformation. Using this model system we sought to identify the earliest epigenetic changes that potentially occur during carcinogenesis. First we show that the transcriptome of vHMEC resembles that of basal-like breast cancer. Moreover, in vHMEC there is significant deregulation of MYC, p53, EZH2/polycomb, the Aryl Hydrocarbon Receptor (AHR) and miRNAs-143, 145, 199a and 519a at the transcriptional level. Second, we find that vHMEC exhibit genome-wide changes in DNA methylation affecting key cancer-associated pathways. Hypermethylation predominately impacted gene promoters (particularly those targeted by AHR and TP53) and polycomb associated loci, whereas hypomethylation frequently affected enhancers. Next we show that long range epigenetic deregulation occurred in vHMEC involving concordant change in chromatin modification and gene expression across ~0.5-1Mb regions. Finally, we demonstrate that the DNA methylation changes we observe in vHMECs, occur in basal-like breast cancer (notably FOXA1 hypermethylation).. Overall our results suggest that the first steps of carcinogenesis are associated with a co-ordinated deregulation of DNA methylation and chromatin modification spanning a range of genomic loci potentially targeted by key transcription factors and a corresponding deregulation of transcriptional networks. We sought to study the chromatin modification profile of human mammary epithelial cells (HMEC) and a matched isogenic variant population (vHMEC) utilising ChIP-seq. ChIP was performed against H3K27ac, H3K36me3 and H3K27me3 for a HMEC and vHMEC timpoint in one donor. H3K4me3 CHIP was performed in two donors, which were treated as biological replicates.

Dataset Information

Sequence and expression analysis of human chromosome 20 gaps

Publications

Sequence and expression analysis of gaps in human chromosome 20.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets