Project description:Chromatin loops are a major componant of 3D nuclear organization that appear as intense point-to-point interactions in Hi-C maps. Identification of these loops is an important part of Hi-C analysis. We present SIP, Significant Interaction Peak caller, a platform independent program to identify these loops in a time and memory efficient manner and which is resistant to noise and sequencing depth. We also present a companion tool, SIPMeta, to create more visually accurate average plots of Hi-C and HiChIP data. We then demonstrate that use of SIP and SIPMeta can lead to biological insight through characterizing the contribution of several transcription factors to CTCF loops in human cells. We then use SIP and SIPMeta to discover loops associated with condensin IDCC in C. elegans and confirm these loops by HiChIP. These loops form a network of interactions and likely explain the partial condensation of dosage compensated X chromosomes in hermaphrodites.
Project description:T-cell prolymphocytic leukemia (T-PLL) is a rare aggressive lymphoma derived from mature T cells, which is, in most cases, characterized by the presence of an inv(14)(q11q32)/t(14;14)(q11;q32) and a characteristic pattern of secondary chromosomal aberrations. DNA microarray technology was employed to compare the transcriptomes of eight immunomagnetically purified CD3+ normal donor-derived peripheral blood cell samples, with five highly purified inv(14)/t(14;14)-positive T-PLL blood samples. Between the two experimental groups, 734 genes were identified as differentially expressed, including functionally important genes involved in lymphomagenesis, cell cycle regulation, apoptosis and DNA repair. Notably, the differentially expressed genes were found to be significantly enriched in genomic regions affected by recurrent chromosomal imbalances. Upregulated genes clustered on chromosome arms 6p and 8q, and downregulated genes on 6q, 8p, 10p, 11q and 18p. High-resolution copy-number determination using single nucleotide polymorphism chip technology in 11 inv(14)/t(14;14)-positive T-PLL and 1 without the inv(14) including those analyzed for gene expression, refined chromosomal breakpoints as well as regions of imbalances. In conclusion, combined transcriptional and molecular cytogenetic profiling identified novel specific chromosomal loci and genes that are likely to be involved in disease progression and suggests a gene dosage effect as a pathogenic mechanism in T-PLL. Each Sample has its raw data file linked as a supplementary file. Keywords: disease state analysis
Project description:T cell prolymphocytic leukemia (T-PLL) is mostly characterized by aberrant expansion of small to medium sized pro-lymphocytes with a mature post-thymic phenotype, high aggressiveness of the disease and poor prognosis. However, T-PLL is more heterogeneous with a wide-range of clinical, morphological, and molecular features, which occasionally impedes the diagnosis. We hypothesized that T-PLL consists of phenotypic and genotypic subgroups that may explain the heterogeneity of the disease. We found that T-PLL does not show a clear skewing in T cell receptor alpha (TRA), TRB gene usage and CDR3 stereotypy. In addition, multi-dimensional immuno-phenotyping and gene expression profiling did not reveal clear T-PLL subgroups. However, based on miRNA expression profiles, T-PLL samples did clearly cluster in subgroups. We identified 35 miRNAs that were aberrantly expressed in T-PLL with miR-200c/141 as the most differentially expressed cluster. High miR-200c/141 expression was significantly correlated with increased white blood cell counts and poor survival. Furthermore, we found that overexpression of miR-200c/141 in T-PLL correlated with downregulation of their targets ZEB2 and TGFβR3, indicating that the TGFβ pathway is affected. Our results thus highlight the emerging role for aberrantly expressed oncogenic miRNAs in T-PLL, thereby paving the way for new therapeutic targets in this disease.
Project description:T cell prolymphocytic leukemia (T-PLL) is mostly characterized by aberrant expansion of small to medium sized pro-lymphocytes with a mature post-thymic phenotype, high aggressiveness of the disease and poor prognosis. However, T-PLL is more heterogeneous with a wide-range of clinical, morphological, and molecular features, which occasionally impedes the diagnosis. We hypothesized that T-PLL consists of phenotypic and genotypic subgroups that may explain the heterogeneity of the disease. We found that T-PLL does not show a clear skewing in T cell receptor alpha (TRA), TRB gene usage and CDR3 stereotypy. In addition, multi-dimensional immuno-phenotyping and gene expression profiling did not reveal clear T-PLL subgroups. However, based on miRNA expression profiles, T-PLL samples did clearly cluster in subgroups. We identified 35 miRNAs that were aberrantly expressed in T-PLL with miR-200c/141 as the most differentially expressed cluster. High miR-200c/141 expression was significantly correlated with increased white blood cell counts and poor survival. Furthermore, we found that overexpression of miR-200c/141 in T-PLL correlated with downregulation of their targets ZEB2 and TGFβR3, indicating that the TGFβ pathway is affected. Our results thus highlight the emerging role for aberrantly expressed oncogenic miRNAs in T-PLL, thereby paving the way for new therapeutic targets in this disease.
Project description:Bioavailability of electron acceptors is probably the most limiting factor in the restoration of anoxic, contaminated environments. The oxidation of contaminants such as aromatic hydrocarbons, particularly in aquifers, often depends on the reduction of ferric iron or sulphate. We have previously detected a highly active fringe zone beneath a toluene plume at a tar-oil contaminated aquifer in Germany, where a specialized community of contaminant degraders co-dominated by Desulfobulbaceae and Geobacteraceae had established. Although on-site geochemistry links degradation to sulphidogenic processes, dominating catabolic (benzylsuccinate synthase alpha-subunit, bssA) genes detected in situ appeared more related to those of Geobacter spp. Therefore, a stable isotope probing (SIP) incubation of sediment samples with 13C7-toluene and comparative electron acceptor amendment was performed. We introduce pyrosequencing of templates from SIP microcosms as a powerful new strategy in SIP gradient interpretation (Pyro-SIP). Our results reveal the central role of Desulfobulbaceae for sulphidogenic toluene degradation in situ, and affiliate the detected bssA genes to this lineage. This, and the absence of 13C-labelled DNA of Geobacter spp. in SIP gradients preclude their relevance as toluene degraders in situ. In contrast, Betaproteobacteria related to Georgfuchsia spp. became labelled under iron-reducing conditions. Furthermore, secondary toluene degraders belonging to the Peptococcaceae detected in both treatments suggest the possibility of functional redundancy amongst anaerobic toluene degraders on site.