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PubMed2004

Overexpression and affinity chromatography purification of the Type III restriction endonuclease EcoP15I for use in transcriptome analysis.

The Type III restriction endonuclease EcoP15I is a multifunctional hetero-oligomeric enzyme that recognizes the non-symmetric DNA sequence 5'-CAGCAG. For efficient cleavage, EcoP15I needs the interaction with two copies of the recognition sequence that have to be inversely oriented in the DNA double strand. The enzyme cuts the upper DNA strand 25-26 bp and the lower DNA strand 27-28 bp, respectively, downstream of the recognition sequence-a distinct feature that makes the enzyme particularly valuable for gene expression profiling methods relying on the SAGE procedure (Matsumura et al., PNAS 100, 15718, 2003). Because the broader use of this transcriptome analysis method requires the availability of larger amounts of restriction endonuclease EcoP15I and the enzyme is not commercially available, we have cloned the genes coding for the EcoP15I restriction endonuclease into pQE-16 plasmid vector that provides the enzyme with a C-terminal 6xHis-tag. After Ni-NTA affinity chromatography and ion exchange chromatography on heparin sepharose, we obtained 5mg homogeneous EcoP15I per gram cell pellet within 1-2 day(s). Moreover, the C-terminally 6xHis-tagged EcoP15I restriction endonuclease shows comparable enzymatic activity as the untagged enzyme.

Amino Acid Sequence↗

PubMed2006

Transcriptome analysis of a shikimic acid producing strain of Escherichia coli W3110 grown under carbon- and phosphate-limited conditions.

Shikimic acid, which is produced in the aromatic amino acid pathway in plants and microorganisms, is an industrially interesting chiral starting material for the synthesis of many chemical substances, e.g. the influenza medicine Tamiflu. When produced by genetically modified Escherichia coli it has previously been found that carbon-rich conditions (e.g. phosphate-limitation) favors production of shikimic acid over shikimate pathway by-products, whereas the situation is the opposite at carbon-(glucose-) limited conditions. In the present study, gene expression patterns of the shikimate producing strain W3110.shik1 (W3110 with aroL deletion and plasmid-overexpressed aroF) and the wild type strain W3110 grown under carbon- and phosphate-limited (carbon-rich) chemostat conditions (D=0.23h(-1)) were analyzed. The study suggests that the by-product formation under carbon-limitation is explained by a set of upregulated genes coupled to the shikimate pathway. The genes, ydiB, aroD and ydiN, were strongly induced only in carbon-limited W3110.shik1. Compared to W3110 the lg(2)-fold changes were: 6.25 (ydiB); 3.93 (aroD) and 8.18 (ydiN). In addition, the transcriptome analysis revealed a large change in the gene expression when comparing phosphate- to carbon-limitation, which to a large part could be explained by anabolic-catabolic uncoupling, which is present under phosphate-limitation but not under carbon-limitation. Interestingly, there was also a larger difference between the two strains under carbon-limitation than under phosphate-limitation. The reason for this difference is interpreted in terms of starvation for aromatic amino acids under carbon-limitation which is relieved under phosphate-limitation due to an upregulation of aroK and aroA.

Bioreactors↗

PubMed2026

Deciphering novel targets in salivary gland pleomorphic adenoma by integrating plasma proteomics and parotid transcriptomics analyses.

BACKGROUND/PURPOSE: Pleomorphic adenoma (PA) is the most common salivary gland benign tumor, with its molecular drivers elusive due to a lack of experimental models. This study aimed to decipher novel targets in PA by systematically integrating plasma protein quantitative trait loci (pQTL)-based Mendelian randomization (MR) with multi-omics profiling of parotid gland tissues. MATERIALS AND METHODS: We performed two-sample MR using 5450 plasma pQTLs and genome-wide association study summary for benign or broader salivary gland diseases from FinnGen consortium. Bulk RNA-sequencing (RNA-seq) and single-cell RNA-seq (scRNA-seq) comparing PA to normal tissue were used for transcriptomic validation. Immunohistochemistry (IHC) was applied for protein-level validation in human PA, adenoid cystic carcinoma (ACC), and murine inflammatory lesions. RESULTS: MR identified 12 plasma proteins associated with benign salivary gland tumor risk. Transmembrane serine protease 6 (TMPRSS6) was the only protein significantly risk-increasing for both benign and broader salivary gland diseases. Strikingly, mitogen-activated protein kinase kinase 4 (MAP2K4) showed opposite MR effects between benign and all-lesion outcomes. Bulk RNA-seq showed limited concordance with MR findings, while scRNA-seq revealed a unique plastic epithelium and partially validated candidates at cellular resolution. Critically, IHC confirmed MAP2K4 protein overexpression specifically in human PA, but not in ACC or inflammatory lesions, while TMPRSS6 was downregulated in established pathologies despite its genetic risk association. CONCLUSION: By integrating plasma proteome-based causal inference with parotid tissue multi-omics, this study unveils MAP2K4 as a potential PA-specific driver. This integrative framework provides novel, context-specific targets for further functional investigation in salivary gland tumorigenesis.

Gene expression profiling↗

PubMed2006

The peripheral blood transcriptome dynamically reflects system wide biology: a potential diagnostic tool.

In our genome-wide survey of gene expression in human peripheral blood cells using both an expressed sequence tag (EST) and a microarray hybridization approach, we identified the expression of a large proportion (approximately 80%) of the genes encoded in the human genome. Comparison of the peripheral blood transcriptome with genes expressed in nine different human tissue types revealed that expression of over 80% was shared with any given tissue. We also sought to determine whether those gene transcripts undetected by these methods were also expressed in peripheral blood cells. Using reverse-transcriptase-polymerase chain reaction, we detected additional tissue-specific gene transcripts including beta-myosin heavy chain (heart specific) and insulin (specific to pancreatic islet beta cells), in circulating blood cells. Arguably, the detection of low levels of tissue-specific transcripts could be considered products of "illegitimate" transcription; however, our study also demonstrates that environmental conditions affect the transcriptional regulation of insulin in the peripheral blood. We thus hypothesize that blood cells can act as sentinels of disease and that we could capitalize on this property of blood for the diagnosis/prognosis of disease (the "Sentinel Principle"). Peripheral blood is an ideal surrogate tissue as it is readily obtainable, provides a large biosensor pool in the form of gene transcripts, and response to changes in the macro- and micro-environments is detectable as alterations in the levels of these gene transcripts.

Blood↗

PubMed2006

Protein/DNA interaction profiling reveals novel regulators of the pineal transcriptome.

The rat pineal gland transcriptome exhibits dynamic daily variation that reflects nocturnally restricted hormone production. Here we have used a protein/DNA interaction array to screen for day-night changes in DNA binding activity that are associated with transcriptional rhythms. Overall, 47 of 54 potential consensus binding sequence activities were detected, and of these, 29 (62%) were found to exhibit day:night differences in level. In addition to known, rhythmic pineal DNA binding activities (CRE and AP-1), multiple novel activities were observed including nocturnally elevated AP-2 consensus sequence binding activity. This array result was validated using conventional DNA binding assays, and we have also demonstrated AP-2beta and AP-2gamma proteins in the pineal gland, in addition to a nocturnally elevated AP-2alpha isoform. Our results have confirmed the presence of a complex assembly of transcriptional rhythms in the rat pineal gland and have provided details of more factors that contribute to this aspect of circadian neuroendocrine function.

Animals↗

PubMed2004

The impact of transcriptome and proteome analyses on antibiotic drug discovery.

Recent scientific publications demonstrate the increasing interest in measurement of genome-wide gene expression on transcript and protein level in response to treatment with antibacterial agents. Nevertheless, the number of large bacterial transcriptome and proteome datasets available so far is limited, although a high number and diversity of antibiotic-triggered expression profiles aid to optimally exploit these technologies. The first published examples substantiate the need to establish these so-called reference compendia of bacterial expression profiles, to discover the molecular mechanism-of-action of uncharacterized bioactive substances. In addition, such compendia open up ways for novel cell-based drug screening approaches.

Anti-Bacterial Agents↗

PubMed2006

Comparison of amplification methods for transcriptomic analyses of low abundance prokaryotic RNA sources.

Microarrays have established as instrumental for bacterial detection, identification, and genotyping as well as for transcriptomic studies. For gene expression analyses using limited numbers of bacteria (derived from in vivo or ex vivo origin, for example), RNA amplification is often required prior to labeling and hybridization onto microarrays. Evaluation of the fidelity of the amplification methods is crucial for the robustness and reproducibility of microarray results. We report here the first utilization of random primers and the highly processive Phi29 phage polymerase to amplify material for transcription profiling analyses. We compared two commercial amplification methods (GenomiPhi and MessageAmp kits) with direct reverse-transcription as the reference method, focusing on the robustness of mRNA quantification using either microarrays or quantitative RT-PCR. Both amplification methods using either poly-A tailing followed by in vitro transcription, or direct strand displacement polymerase, showed appreciable linearity. Strand displacement technique was particularly affordable compared to in vitro transcription-based (IVT) amplification methods and consisted in a single tube reaction leading to high amplification yields. Real-time measurements using low-, medium-, and highly expressed genes revealed that this simple method provided linear amplification with equivalent results in terms of relative messenger abundance as those obtained by conventional direct reverse-transcription.

Nucleic Acid Amplification Techniques↗

PubMed2005

The Plasmodium falciparum sexual development transcriptome: a microarray analysis using ontology-based pattern identification.

The sexual stages of malarial parasites are essential for the mosquito transmission of the disease and therefore are the focus of transmission-blocking drug and vaccine development. In order to better understand genes important to the sexual development process, the transcriptomes of high-purity stage I-V Plasmodium falciparum gametocytes were comprehensively profiled using a full-genome high-density oligonucleotide microarray. The interpretation of this transcriptional data was aided by applying a novel knowledge-based data-mining algorithm termed ontology-based pattern identification (OPI) using current information regarding known sexual stage genes as a guide. This analysis resulted in the identification of a sexual development cluster containing 246 genes, of which approximately 75% were hypothetical, exhibiting highly-correlated, gametocyte-specific expression patterns. Inspection of the upstream promoter regions of these 246 genes revealed putative cis-regulatory elements for sexual development transcriptional control mechanisms. Furthermore, OPI analysis was extended using current annotations provided by the Gene Ontology Consortium to identify 380 statistically significant clusters containing genes with expression patterns characteristic of various biological processes, cellular components, and molecular functions. Collectively, these results, available as part of a web-accessible OPI database (http://carrier.gnf.org/publications/Gametocyte), shed light on the components of molecular mechanisms underlying parasite sexual development and other areas of malarial parasite biology.

Animals↗

PubMed2006

Impact of intestinal colonization and invasion on the Entamoeba histolytica transcriptome.

A genome-wide transcriptional analysis of Entamoeba histolytica was performed on trophozoites isolated from the colon of six infected mice and from in vitro culture. An Affymetrix platform gene expression array was designed for this analysis that included probe sets for 9435 open reading frames (ORFs) and 9066 5' and 3' flanking regions. Transcripts were detected for > 80% of all ORFs. A total of 523 transcripts (5.2% of all E. histolytica genes) were significantly changed in amebae isolated from the intestine on Days 1 and 29 after infection: 326 and 109 solely on Days 1 and 29, and 88 on both days. Quantitative real-time reverse transcriptase PCR confirmed these changes in 11/12 genes tested using mRNA isolated from an additional six mice. Adaptation to the intestinal environment was accompanied by increases in a subset of cell signaling genes including transmembrane kinases, ras and rho family GTPases, and calcium binding proteins. Significant decreases in mRNA abundance for genes involved in glycolysis and concomitant increases in lipases were consistent with a change in energy metabolism. Defense against bacteria present in the intestine (but lacking from in vitro culture) was suggested by alterations in mRNA levels of genes similar to the AIG1 plant antibacterial proteins. Decreases in oxygen detoxification pathways were observed as expected in the anaerobic colonic lumen. Of the known virulence factors the most remarkable changes were a 20-35-fold increase in a cysteine proteinase four-like gene, and a 2-3-fold decrease in two members of the Gal/GalNAc lectin light subunit family. Control of the observed changes in mRNA abundance in the intestine might potentially rest with four related proteins with DNA binding domains that were down-regulated 6-16-fold in the intestinal environment. In conclusion, the first genome-wide analysis of the transcriptome of E. histolytica demonstrated that the vast majority of genes are transcribed in trophozoites, and that in the host intestine trophozoites altered the expression of mRNAs for genes implicated in metabolism, oxygen defense, cell signaling, virulence, antibacterial activity, and DNA binding.

Animals↗

PubMed2006

Comparative transcriptomal analysis of isogenic Plasmodium falciparum clones of distinct antigenic and adhesive phenotypes.

Antigenic variation is a survival mechanism developed by the malaria parasite Plasmodium falciparum in order to allow for the establishment of a chronic infection. Here we have studied clonal differences in the transcriptomes of two isogenic P. falciparum clones (3D7S8.4 and 3D7AH1S2) of distinct adhesive and antigenic phenotypes employing a P. falciparum 70-mer oligonucleotide microarray. Fifteen transcripts were highly differentially expressed (greater than a 5-fold change) with five transcripts upregulated in 3D7AH1S2 compared to 3D7S8.4, and ten downregulated. Identified genes encode apical organellar (Gbph2, GBP-related antigen), cell cycle and DNA/RNA processing (SERA-5, RNA-methylase), cell-rescue, defense/virulence (RESA-2, RIFIN, PfEMP1) and hypothetical proteins (PFB0115w, PFI1445w, MAL13P1.121). A number of short and full-length var transcripts were differentially expressed between the clones but one full-length transcript was dominant in both rings and trophozoites (PFD0630c versus PFF0845c). Distinct members of two other variant gene families (phist-a and rif-like), scattered over the subtelomeric areas of the 14 chromosomes, were also found to be clonally and developmentally expressed. Three sibling-clones of 3D7AH1S2 (3D7AH1S1, -S3, -S4) were further studied for the expression of transcripts upregulated in 3D7AH1S2 compared to 3D7S8.4. Individual var and phist-a genes were found expressed in all of the clones while the expression of a rif-like gene and gbph2 varied in-between the clones. The present data provides evidence for complex transcriptional differences between closely related isogenic P. falciparum of distinct adhesive and antigenic characteristics.

Animals↗

PubMed2005

Transcriptome profiling of adult zebrafish at the late stage of chronic tuberculosis due to Mycobacterium marinum infection.

The Mycobacterium marinum-zebrafish infection model was used in this study for analysis of a host transcriptome response to mycobacterium infection at the organismal level. RNA isolated from adult zebrafish that showed typical signs of fish tuberculosis due to a chronic progressive infection with M. marinum was compared with RNA from healthy fish in microarray analyses. Spotted oligonucleotide sets (designed by Sigma-Compugen and MWG) and Affymetrix GeneChips were used, in total comprising 45,465 zebrafish transcript annotations. Based on a detailed comparative analysis and quantitative reverse transcriptase-PCR analysis, we present a validated reference set of 159 genes whose regulation is strongly affected by mycobacterial infection in the three types of microarrays analyzed. Furthermore, we analyzed the separate datasets of the microarrays with special emphasis on the expression profiles of immune-related genes. Upregulated genes include many known components of the inflammatory response and several genes that have previously been implicated in the response to mycobacterial infections in cell cultures of other organisms. Different marker genes of the myeloid lineage that have been characterized in zebrafish also showed increased expression. Furthermore, the zebrafish homologs of many signal transduction genes with relationship to the immune response were induced by M. marinum infection. Future functional analysis of these genes may contribute to understanding the mechanisms of mycobacterial pathogenesis. Since a large group of genes linked to immune responses did not show altered expression in the infected animals, these results suggest specific responses in mycobacterium-induced disease.

Animals↗

PubMed2004

Schistosome transcriptomes: new insights into the parasite and schistosomiasis.

Schistosomiasis is one of the most serious parasitic diseases. More than 250 million people are infected with schistosomes in the tropics or subtropics. The parasitic flukes have some unique biological features: dioecism, complex life cycles, mechanisms to avoid host immune responses, and an apparent reliance on host endocrine and immune signals to complete their development, maturation and egg production. Recently, a large dataset of expressed sequence tags (ESTs) were generated from Schistosoma japonicum and Schistosoma mansoni, from which numerous novel genes were identified. The transcriptome analyses provide the basis for a comprehensive understanding of the molecular mechanisms involved in schistosome nutrition and metabolism, host-dependent development and maturation, immune evasion and invertebrate evolution. In addition, new potential vaccine candidates and drug targets have been predicted.

Animals↗

PubMed2006

Components of the peptidome and transcriptome persist in lin wa pi: the dried skin of the Heilongjiang brown frog (Rana amurensis) as used in traditional Chinese medicine.

Although the ancient practice of traditional Chinese medicine (TCM) utilizes predominantly herbal ingredients, many of which are now the subject of intense scientific scrutiny, significant quantities of animal tissue-derived materials are also employed. Here we have used contemporary molecular techniques to study the material known as lin wa pi, the dried skin of the Heilongjiang brown frog, Rana amurensis, that is used commonly as an ingredient of many medicines, as a general tonic and as a topical antimicrobial/wound dressing. Using a simple technology that has been developed and validated over several years, we have demonstrated that components of both the skin granular gland peptidome and transcriptome persist in this material. Interrogation of the cDNA library constructed from the dried skin by entrapment and amplification of polyadenylated mRNA, using a "shotgun" primer approach and 3'-RACE, resulted in the cloning of cDNAs encoding the precursors of five putative antimicrobial peptides. Two (ranatuerin-2AMa and ranatuerin-2AMb) were obvious homologs of a previously described frog skin peptide family, whereas the remaining three were of sufficient structural novelty to be named amurins 1-3. Mature peptides were each identified in reverse phase HPLC fractions of boiling water extracts of skin and their structures confirmed by MS/MS fragmentation sequencing. Components of traditional Chinese medicines of animal tissue origin may thus contain biologically active peptides that survive the preparation procedures and that may contribute to therapeutic efficacy.

Air↗

PubMed2004

Schistosome transcriptome analysis at the cutting edge.

We live in the era of post-genomics, a term that was, until recently, inappropriate when considering the blood flukes of humans because of the relative lack of knowledge of the schistosome genome. The position has, however, changed dramatically following the recent publication of two landmark papers on transcriptome analysis of Schistosoma japonicum and Schistosoma mansoni. In a quantum leap, both studies report on the identification of many novel genes and genes not previously known from schistosomes. The datasets provide new insights into the biology of the schistosomes and offer an opportunity for identification of potential antischistosome vaccine candidates and drug targets. Remarkable recent progress has also been achieved in genomic sequencing, and completed genomes for both species can be expected shortly.

Animals↗

PubMed2026

Genomic and transcriptomic quality control for an autologous iPSC-derived cell therapy for Parkinson's disease.

Toward development of an autologous, induced pluripotent stem cell (iPSC)-based cell therapy for Parkinson's disease (PD), we demonstrate successful, reproducible genomic and transcriptomic qualification of patient-derived dopaminergic neuron precursor cells (DANPCs) across multiple donors. Our analysis includes whole-genome sequencing data from fibroblasts, iPSCs, and DANPCs and the development of NeuriTest, an RNAseq-based bioinformatic analysis of DANPCs designed to predict cell quality based on empirical animal data. Autologous cell therapies are immune matched to the patient, potentially augmenting durability of benefit compared to allogeneic cells while negating the need for immunosuppression and accompanying side effects. Patient-specific iPSCs are an autologous cell source that can be differentiated to dopaminergic neurons, the cell type lost in PD. We report here our preclinical manufacturing strategy and results demonstrating efficacy in a PD rodent model and safety in a 9-month GLP toxicology study.

Parkinson’s disease↗

PubMed2005

Molecular signature analysis: using the myocardial transcriptome as a biomarker in cardiovascular disease.

With the emergence of microarray technology, it is now possible to simultaneously assess the expression of tens of thousands of gene transcripts, providing a resolution and precision of phenotypic characterization not previously possible. In the field of cardiomyopathy, microarray studies have largely focused on gene discovery, identifying differentially expressed genes characteristic of diverse disease states, through which novel genetic pathways and potential therapeutic targets may be elucidated. However, gene expression profiling may also be used to identify a pattern of genes (a molecular signature) that serves as a biomarker for clinically relevant parameters. One study thus far does demonstrate that a molecular signature can accurately identify etiology in cardiovascular disease, supporting ongoing efforts to incorporate expression-profiling-based biomarkers in determining prognosis and response to therapy in heart failure. Microarray research in cardiomyopathy is still in its earliest stages. Nevertheless, the ultimate potential application of transcriptome-based molecular signature analysis is individualization of the management of patients with heart failure, whereby a patient with a newly diagnosed cardiomyopathy could, through molecular signature analysis, be offered an accurate assessment of prognosis and how individualized medical therapy could affect his or her outcome.

Biomarkers↗

PubMed2004

The maturing of the human embryonic stem cell transcriptome profile.

Several recent reports used microarray, serial analysis of gene expression (SAGE), and expressed sequence tags (EST) strategies to characterize the human embryonic stem cell transcriptome and those of their differentiated derivatives. All three approaches yielded valuable data and highlight the fact that a large percentage of genes remain uncharacterized in these cells representative of early human development.

Databases as Topic↗

PubMed2026

Dynamic evolution of chaperone-mediated autophagy is associated with tumor microenvironment remodeling and prognostic stratification in lung adenocarcinoma: insights from single-cell transcriptomics, ensemble machine learning, and experimental validation.

BACKGROUND: Lung adenocarcinoma (LUAD) shows prognostic heterogeneity, and tumor-node-metastasis (TNM) staging is limited for individualized management. Chaperone-mediated autophagy (CMA) maintains proteostasis, but its role during adenocarcinoma in situ (AIS)-minimally invasive adenocarcinoma (MIA)-invasive adenocarcinoma (IAC) progression remains unclear. METHODS: Single-cell RNA sequencing (scRNA-seq) data from GSE189357 and bulk transcriptomes from The Cancer Genome Atlas (TCGA)-LUAD and Gene Expression Omnibus (GEO) cohorts were integrated. CMA activity, cell-cell communication, weighted gene co-expression network analysis (WGCNA), tumor-normal differential expression, machine-learning survival modeling, tumor microenvironment (TME) features, drug sensitivity, and EPC1 function were analyzed. RESULTS: CMA-high tumor epithelial cells increased from AIS (58.1%) to MIA (65.7%) but declined in IAC (44.4%; p < 0.001). CMA-low cells preferentially received fibroblast-derived extracellular matrix cues. A CMA-negatively correlated module identified 69 core genes. Random survival forest (RSF) performed best among 117 machine-learning combinations (mean concordance index > 0.873). High-risk patients had worse survival across cohorts, and the risk score was independently associated with overall survival (hazard ratio = 16.013, 95% confidence interval: 9.579-26.768, p < 0.001). High-risk tumors showed proliferative activation and M0 macrophage enrichment, whereas low-risk tumors showed stronger immune-related signaling. EPC1 overexpression suppressed malignant phenotypes in A549 cells. CONCLUSION: CMA dynamics are associated with stromal and immune remodeling during LUAD progression. A CMA-based model provides robust prognostic stratification and may offer a basis for future TME-guided studies.

Chaperone-mediated autophagy↗