The “Gene Cube”: A Novel Approach to Three-dimensional Clustering of Gene Expression Data

2019 ◽  
Vol 14 (8) ◽  
pp. 721-727 ◽  
Author(s):  
George I. Lambrou ◽  
Maria Sdraka ◽  
Dimitrios Koutsouris
Keyword(s):  
Gene Expression ◽  
Clustering Algorithms ◽  
Expression Patterns ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Tissue Samples ◽  
Novel Approach ◽  
Local Background ◽  
3D Matrix ◽  
Public Datasets

Background: A very popular technique for isolating significant genes from cancerous tissues is the application of various clustering algorithms on data obtained by DNA microarray experiments. Aim: The objective of the present work is to take into consideration the chromosomal identity of every gene before the clustering, by creating a three-dimensional structure of the form Chromosomes×Genes×Samples. Further on, the k-Means algorithm and a triclustering technique called δ- TRIMAX, are applied independently on the structure. Materials and Methods: The present algorithm was developed using the Python programming language (v. 3.5.1). For this work, we used two distinct public datasets containing healthy control samples and tissue samples from bladder cancer patients. Background correction was performed by subtracting the median global background from the median local Background from the signal intensity. The quantile normalization method has been applied for sample normalization. Three known algorithms have been applied for testing the “gene cube”, a classical k-means, a transformed 3D k-means and the δ-TRIMAX. Results: Our proposed data structure consists of a 3D matrix of the form Chromosomes×Genes×Samples. Clustering analysis of that structure manifested very good results as we were able to identify gene expression patterns among samples, genes and chromosomes. Discussion: to the best of our knowledge, this is the first time that such a structure is reported and it consists of a useful tool towards gene classification from high-throughput gene expression experiments. Conclusion: Such approaches could prove useful towards the understanding of disease mechanics and tumors in particular.

scholarly journals The Three-Dimensional Structure of Human Interphase Chromosomes Is Related to the Transcriptome Map

2007 ◽  
Vol 27 (12) ◽  
pp. 4475-4487 ◽  
Author(s):  
Sandra Goetze ◽  
Julio Mateos-Langerak ◽  
Hinco J. Gierman ◽  
Wim de Leeuw ◽  
Osdilly Giromus ◽  
...  
Keyword(s):  
Gene Expression ◽  
Structural Parameters ◽  
Expression Patterns ◽  
Genome Structure ◽  
Three Dimensional ◽  
Chromosome Territory ◽  
Dimensional Structure ◽  
Compact Structure ◽  
General Aspects ◽  
And Function

ABSTRACT The three-dimensional (3D) organization of the chromosomal fiber in the human interphase nucleus is an important but poorly understood aspect of gene regulation. Here we quantitatively analyze and compare the 3D structures of two types of genomic domains as defined by the human transcriptome map. While ridges are gene dense and show high expression levels, antiridges, on the other hand, are gene poor and carry genes that are expressed at low levels. We show that ridges are in general less condensed, more irregularly shaped, and located more closely to the nuclear center than antiridges. Six human cell lines that display different gene expression patterns and karyotypes share these structural parameters of chromatin. This shows that the chromatin structures of these two types of genomic domains are largely independent of tissue-specific variations in gene expression and differentiation state. Moreover, we show that there is remarkably little intermingling of chromatin from different parts of the same chromosome in a chromosome territory, neither from adjacent nor from distant parts. This suggests that the chromosomal fiber has a compact structure that sterically suppresses intermingling. Together, our results reveal novel general aspects of 3D chromosome architecture that are related to genome structure and function.

Confocal laser microscopy of impregnated central nervous system tissue

1988 ◽  
Vol 46 ◽  
pp. 94-95
Author(s):  
J.N. Turner ◽  
M. Siemens ◽  
D. Szarowski ◽  
D.N. Collins
Keyword(s):  
Electron Microscopy ◽  
Central Nervous System ◽  
Nervous System ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Confocal Laser ◽  
High Contrast ◽  
Central Nervous System Tissue ◽  
Tissue Samples ◽  
Reflected Light

A classic preparation of central nervous system tissue (CNS) is the Golgi procedure popularized by Cajal. The method is partially specific as only a few cells are impregnated with silver chromate usualy after osmium post fixation. Samples are observable by light (LM) or electron microscopy (EM). However, the impregnation is often so dense that structures are masked in EM, and the osmium background may be undesirable in LM. Gold toning is used for a subtle but high contrast EM preparation, and osmium can be omitted for LM. We are investigating these preparations as part of a study to develop correlative LM and EM (particularly HVEM) methodologies in neurobiology. Confocal light microscopy is particularly useful as the impregnated cells have extensive three-dimensional structure in tissue samples from one to several hundred micrometers thick. Boyde has observed similar preparations in the tandem scanning reflected light microscope (TSRLM).

scholarly journals Bayesian Framework for Detecting Gene Expression Outliers in Individual Samples

2020 ◽  
pp. 160-170
Author(s):  
John Vivian ◽  
Jordan M. Eizenga ◽  
Holly C. Beale ◽  
Olena M. Vaske ◽  
Benedict Paten
Keyword(s):  
Gene Expression ◽  
Expression Patterns ◽  
Rna Seq ◽  
Single Patient ◽  
Tissue Samples ◽  
Composite Tissue ◽  
Patient Sample ◽  
Statistical Framework ◽  
Therapeutic Leads ◽  
Upregulated Genes

PURPOSE Many antineoplastics are designed to target upregulated genes, but quantifying upregulation in a single patient sample requires an appropriate set of samples for comparison. In cancer, the most natural comparison set is unaffected samples from the matching tissue, but there are often too few available unaffected samples to overcome high intersample variance. Moreover, some cancer samples have misidentified tissues of origin or even composite-tissue phenotypes. Even if an appropriate comparison set can be identified, most differential expression tools are not designed to accommodate comparisons to a single patient sample. METHODS We propose a Bayesian statistical framework for gene expression outlier detection in single samples. Our method uses all available data to produce a consensus background distribution for each gene of interest without requiring the researcher to manually select a comparison set. The consensus distribution can then be used to quantify over- and underexpression. RESULTS We demonstrate this method on both simulated and real gene expression data. We show that it can robustly quantify overexpression, even when the set of comparison samples lacks ideally matched tissue samples. Furthermore, our results show that the method can identify appropriate comparison sets from samples of mixed lineage and rediscover numerous known gene-cancer expression patterns. CONCLUSION This exploratory method is suitable for identifying expression outliers from comparative RNA sequencing (RNA-seq) analysis for individual samples, and Treehouse, a pediatric precision medicine group that leverages RNA-seq to identify potential therapeutic leads for patients, plans to explore this method for processing its pediatric cohort.

scholarly journals 1450-1545 Young Investigator Awards & Presentations Basic/Translational Exploring cellular subpopulations in glioblastoma and matched organoids using single-cell RNA-seq 52

2018 ◽  
Vol 45 (S3) ◽  
pp. S13-S14
Author(s):  
VG LeBlanc ◽  
D Trinh ◽  
M Hughes ◽  
I Luthra ◽  
D Livingstone ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Tissue Sample ◽  
Expression Patterns ◽  
Model Systems ◽  
Sequencing Data ◽  
Tissue Samples ◽  
Original Tumour ◽  
Current Therapies ◽  
Intratumoural Heterogeneity

Glioblastomas (GBMs) account for nearly half of all primary malignant brain tumours, and current therapies are often only marginally effective. Our understanding of the underlying biology of these tumours and the development of new therapies have been complicated in part by widespread inter- and intratumoural heterogeneity. To characterize this heterogeneity, we performed regional subsampling of primary glioblastomas and derived organoids from these tissue samples. We then performed single-cell RNA-sequencing (scRNA-seq) on these primary regional subsamples and 1-3 matched organoids per sample. We have profiled samples from six tumour sets to date and have obtained sequencing data for 21,234 primary tissue cells and 14,742 organoid cells. While the most apparent differences in gene expression appear to be between individual tumours, we were also able to identify similar cellular subpopulations across tissue samples and across organoids. Importantly, organoids derived from the same tissue sample appeared to be composed of similar cellular subpopulations and were highly comparable to each other, indicating that replicate organoids faithfully represent the original tumour tissue. Overall, our scRNA-seq approach will help evaluate the utility of tumour-derived organoids as model systems for GBM and will aid in identifying cellular subpopulations defined by gene expression patterns, both in primary GBM regional subsamples and their associated organoids. These analyses will allow for the characterization of clonal or subclonal populations that are likely to respond to different therapeutic approaches and may also uncover novel therapeutic targets previously unrevealed through bulk analyses.

A murrel cysteine protease, cathepsin L: bioinformatics characterization, gene expression and proteolytic activity

Biologia ◽  
2014 ◽  
Vol 69 (3) ◽  
Author(s):  
Venkatesh Kumaresan ◽  
Prasanth Bhatt ◽  
Rajesh Palanisamy ◽  
Annie Gnanam ◽  
Mukesh Pasupuleti ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bacterial Infections ◽  
Cathepsin L ◽  
Three Dimensional ◽  
Structural Similarity ◽  
Data Bank ◽  
Minimum Free Energy ◽  
Dimensional Structure ◽  
Peptide Bonds ◽  
Gene Expression Studies

AbstractCathepsin L, a lysosomal endopeptidase, is a member of the peptidase C1 family (papain-like family) of cysteine proteinases that cleave peptide bonds of lysosomal proteins. In this study, we report a cathepsin L sequence identified from the constructed cDNA library of striped murrel Channa striatus (designated as CsCath L) using genome sequencing FLXTM technology. The full-length CsCath L contains three eukaryotic thiol protease domains at positions 134-145, 278-288 and 299-318. Phylogenetic analysis revealed that the CsCath L was clustered together with other cathepsin L from teleosts. The three-dimensional structure of CsCath L modelled by the I-Tasser program was compared with structures deposited in the Protein Data Bank to find out the structural similarity of CsCath L with experimentally identified structures. The results showed that the CsCath L exhibits maximum structural identity with pro-cathepsin L from human. The RNA fold structure of CsCath L was predicted along with its minimum free energy (−471.93 kcal/mol). The highest CsCath L gene expression was observed in liver, which was also significantly higher (P < 0.05) than that detected in other tissues taken for analysis. In order to investigate the mRNA transcription profile of CsCath L during infection, C. striatus were injected with fungus (Aphanomyces invadans) and bacteria (Aeromonas hydrophila) and its expression was up-regulated in liver at various time points. Similar to gene expression studies, the highest CsCath L enzyme activity was also observed in liver and its activity was up-regulated by fungal and bacterial infections.

RNA-sequencing and bioinformatic analysis to pre-assess sensitivity to targeted therapeutics in recurrent glioblastoma.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e13533-e13533
Author(s):  
Ella L Kim ◽  
Anton Buzdin ◽  
Maxim Sorokin ◽  
Elena Poddubskaya ◽  
Artem Poddubskiy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Rna Sequencing ◽  
Cell Cultures ◽  
Radiation Treatment ◽  
Clinical Stage ◽  
Expression Patterns ◽  
Recurrent Glioblastoma ◽  
Targeted Therapeutics ◽  
Biopsy Material ◽  
Tissue Samples

e13533 Background: This study developed molecular guided tools for individualized selection of chemotherapeutics for recurrent glioblastoma (rGB). A consortium involving clinical neurooncologists, molecular biologists and bioinformaticians identified gene expression patterns in rGB and quantitatively analyzed pathways involved in response to FDA approved oncodrugs. Methods: From2016 to 2018 biopsies from GB were collected using a multisampling approach. Biopsy material was used to isolate glioma stem-like cells and examined by RNA-sequencing. RNA-seq results were subjected to differential expression (DE) analysis and Oncobox analysis – a bioinformatic tool for quantitative pathway activation analysis. Results for newly diagnosed (nGB) and rGB (tissue samples and cell cultures) were compared. Oncobox analysis was further used to examine differential activation of pathways involved in response to existing chemotherapeutics. Results: 128 tissue samples and 28 cell cultures from a total of 44 GBs including 23 nGB, 19 rGB and 2 second-recurrent GBs were analyzed. 14 patient-matched pairs of nGB and rGB were obtained. DE analysis of nGB and rGB, showed a distinct “signature” associated with rGB. Oncobox analysis found down regulation of pathways related to cell cycle and DNA repair and upregulation of immune response pathways in rGB vs corresponding nGB. Specifically, pathways targeted by temozolomide, which is the first line chemotherapy for GB, were found down regulated in rGB. Among the top pathways upregulated in rGB were the pathways targeted by durvalumab and pomalidomide currently under investigation in phase II or III trials for GB. Conclusions: Specific pathway analysis revealed regional and clinical stage-associated differences in the transcriptional landscapes of nGB and rGB. Our results support a concept of treatment-induced resistance to cytotoxic therapeutics and indicate that temozolomide and radiation treatment have important impacts on gene expression changes associated with GB recurrence. Systematic molecular profiling of rGB is a promising avenue towards predicting sensitivity to targeted therapeutics in rGBs on an individual basis.

scholarly journals Global Analysis of Cell Type-Specific Gene Expression

2003 ◽  
Vol 4 (2) ◽  
pp. 208-215 ◽  
Author(s):  
David W. Galbraith
Keyword(s):  
Gene Expression ◽  
Fluorescent Protein ◽  
Global Analysis ◽  
Expression Patterns ◽  
Three Dimensional ◽  
Global Gene Expression ◽  
Cell Types ◽  
Reasonable Assumption ◽  
Specific Gene ◽  
Different Cell Types

The tissues and organs of multicellular eukaryotes are frequently observed to comprise complex three-dimensional interspersions of different cell types. It is a reasonable assumption that different global patterns of gene expression are found within these different cell types. This review outlines general experimental strategies designed to characterize these global gene expression patterns, based on a combination of methods of transgenic fluorescent protein (FP) expression and targeting, of flow cytometry and sorting and of high-throughput gene expression analysis.

scholarly journals Spatial organization of different sigma factor activities and c-di-GMP signalling within the three-dimensional landscape of a bacterial biofilm

Open Biology ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 180066 ◽  
Author(s):  
Gisela Klauck ◽  
Diego O. Serra ◽  
Alexandra Possling ◽  
Regine Hengge
Keyword(s):  
Gene Expression ◽  
Extracellular Matrix ◽  
Stationary Phase ◽  
Sigma Factor ◽  
Spatial Organization ◽  
Expression Patterns ◽  
Three Dimensional ◽  
Biomechanical Properties ◽  
Ribosomal Gene ◽  
Bacterial Biofilm

Bacterial biofilms are large aggregates of cells embedded in an extracellular matrix of self-produced polymers. In macrocolony biofilms of Escherichia coli , this matrix is generated in the upper biofilm layer only and shows a surprisingly complex supracellular architecture. Stratified matrix production follows the vertical nutrient gradient and requires the stationary phase σ S (RpoS) subunit of RNA polymerase and the second messenger c-di-GMP. By visualizing global gene expression patterns with a newly designed fingerprint set of Gfp reporter fusions, our study reveals the spatial order of differential sigma factor activities, stringent control of ribosomal gene expression and c-di-GMP signalling in vertically cryosectioned macrocolony biofilms. Long-range physiological stratification shows a duplication of the growth-to-stationary phase pattern that integrates nutrient and oxygen gradients. In addition, distinct short-range heterogeneity occurs within specific biofilm strata and correlates with visually different zones of the refined matrix architecture. These results introduce a new conceptual framework for the control of biofilm formation and demonstrate that the intriguing extracellular matrix architecture, which determines the emergent physiological and biomechanical properties of biofilms, results from the spatial interplay of global gene regulation and microenvironmental conditions. Overall, mature bacterial macrocolony biofilms thus resemble the highly organized tissues of multicellular organisms.

Abstracts of the 5th International Conference on Lactoferrin / Résumés du 5e symposium internationeige sur la lactoferrin

2002 ◽  
Vol 80 (1) ◽  
pp. 137-168
Keyword(s):  
Gene Expression ◽  
Cancer Treatment ◽  
Structure Function ◽  
Gene Expression Regulation ◽  
Three Dimensional ◽  
Antimicrobial Properties ◽  
Dimensional Structure ◽  
International Conference ◽  
Immunological Effects ◽  
Potential Use

Sixty-three abstracts are presented from the 5th International Conference on Lactoferrin "Structure, Function and Applications" in Banff, Alberta. The conference focused on lactoferrin’s three-dimensional structure, antimicrobial properties, immunological effects, potential use in cancer treatment, gene expression regulation, and receptors.

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