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At least 667 records · Page 37Linked to original sources
PubMed2004

Incidence of "quasi-ditags" in catalogs generated by Serial Analysis of Gene Expression (SAGE).

BACKGROUND: Serial Analysis of Gene Expression (SAGE) is a functional genomic technique that quantitatively analyzes the cellular transcriptome. The analysis of SAGE libraries relies on the identification of ditags from sequencing files; however, the software used to examine SAGE libraries cannot distinguish between authentic versus false ditags ("quasi-ditags"). RESULTS: We provide examples of quasi-ditags that originate from cloning and sequencing artifacts (i.e. genomic contamination or random combinations of nucleotides) that are included in SAGE libraries. We have employed a mathematical model to predict the frequency of quasi-ditags in random nucleotide sequences, and our data show that clones containing less than or equal to 2 ditags (which include chromosomal cloning artifacts) should be excluded from the analysis of SAGE catalogs. CONCLUSIONS: Cloning and sequencing artifacts contaminating SAGE libraries could be eliminated using simple pre-screening procedure to increase the reliability of the data.

Animals↗
PubMed2026

Impact of Tumor Genomic Profile on Adjuvant Chemotherapy Efficacy in Resected Pancreatic Adenocarcinoma: Results From the PRODIGE-24/CCTG PA6 Study.

PURPOSE: Modified fluorouracil, leucovorin, irinotecan, and oxaliplatin (mFOLFIRINOX/mFFX) is the standard adjuvant chemotherapy for resected pancreatic ductal adenocarcinoma (PDAC), offering survival benefits over gemcitabine (GEM). However, the contribution of molecular biomarkers to treatment selection remains unclear. Here, we characterize the molecular landscape of tumors from the PRODIGE-24/CCTG PA6 trial and assess the clinical impact of genomic alterations and molecular subtypes. PATIENTS AND METHODS: Tumor DNA sequencing was successfully performed in 317/350 tumors (168 mFFX; 149 GEM), complemented by transcriptomic subtyping using the PurIST classifier. Mutational status of four key PDAC driver genes and 24 homologous recombination repair (HRR)-associated genes was analyzed, alongside single-base substitution (SBS) mutational signatures. Primary and secondary end points were disease-free survival (DFS) and cancer-specific survival (CSS), respectively. RESULTS: In the mFFX group, the PurIST subtype was prognostic, with classical tumors showing superior DFS compared with basal-like tumors (stratified hazard ratio [sHR], 0.48 [95% CI, 0.31 to 0.77]). Among KRAS-mutated patients, mFFX significantly improved DFS compared with GEM (sHR, 0.60 [95% CI, 0.45 to 0.79]; P < .001), while no benefit was observed in KRAS wild-type tumors (interaction test, Pint. = 0.010). HRR and BRCA status were not predictive (Pint. = .568 and Pint. = .785, respectively). The benefit of mFFX was consistent across SBS-positive and SBS-negative subgroups. CONCLUSION: Overall, these results do not support a change in current adjuvant treatment strategies. mFFX remains the standard adjuvant regimen in PDAC, and the observed lack of benefit in KRAS wild-type tumors should be considered hypothesis-generating and warrants further investigation.

Humans↗
PubMed2025

Repression of CADM1 transcription by HPV type 18 is mediated by three-dimensional rearrangement of promoter-enhancer interactions.

Upon infection, human papillomavirus (HPV) manipulates host cell gene expression to create an environment that is supportive of a productive and persistent infection. The virus-induced changes to the host cell's transcriptome are thought to contribute to carcinogenesis. Here, we show by RNA-sequencing that oncogenic HPV18 episome replication in primary human foreskin keratinocytes (HFKs) drives host transcriptional changes that are consistent between multiple HFK donors. We have previously shown that HPV18 recruits the host protein CTCF to viral episomes to control the differentiation-dependent viral transcriptional programme. Since CTCF is an important regulator of host cell transcription via coordination of epigenetic boundaries and long-range chromosomal interactions, we hypothesised that HPV18 may also manipulate CTCF to contribute to host transcription reprogramming. Analysis of CTCF binding in the host cell genome by ChIP-Seq revealed that while the total number of CTCF binding sites is not altered by the virus, there are a sub-set of CTCF binding sites that are either enriched or depleted of CTCF. Many of these altered sites are clustered within regulatory elements of differentially expressed genes, including the tumour suppressor gene cell adhesion molecule 1 (CADM1), which supresses epithelial cell growth and invasion. We show that HPV18 establishment results in reduced CTCF binding at the CADM1 promoter and upstream enhancer. Loss of CTCF binding is coincident with epigenetic repression of CADM1, in the absence of CpG hypermethylation, while adjacent genes including the transcriptional regulator ZBTB16 are activated. These data indicate that the CADM1 locus is subject to topological rearrangement following HPV18 establishment. We tested this hypothesis using 4C-Seq (circular chromosome confirmation capture-sequencing) and show that HPV18 establishment causes a loss of long-range chromosomal interactions between the CADM1 transcriptional start site and the upstream transcriptional enhancer. These data show that HPV18 manipulates host cell promoter-enhancer interactions to drive transcriptional reprogramming that may contribute to HPV-induced disease progression.

Humans↗
PubMed2005

Transcriptome profiling of human and murine ESCs identifies divergent paths required to maintain the stem cell state.

Human embryonic stem cells (hESCs) are an important source of stem cells in regenerative medicine, and much remains unknown about their molecular characteristics. To develop a detailed genomic profile of ESC lines in two different species, we compared transcriptomes of one murine and two different hESC lines by massively parallel signature sequencing (MPSS). Over 2 million signature tags from each line and their differentiating embryoid bodies were sequenced. Major differences and conserved similarities between species identified by MPSS were validated by reverse transcription polymerase chain reaction (RT-PCR) and microarray. The two hESC lines were similar overall, with differences that are attributable to alleles and propagation. Human-mouse comparisons, however, identified only a small (core) set of conserved genes that included genes known to be important in ESC biology, as well as additional novel genes. Identified were major differences in leukemia inhibitory factor, transforming growth factor-beta, and Wnt and fibroblast growth factor signaling pathways, as well as the expression of genes encoding metabolic, cytoskeletal, and matrix proteins, many of which were verified by RT-PCR or by comparing them with published databases. The study reported here underscores the importance of cross-species comparisons and the versatility and sensitivity of MPSS as a powerful complement to current array technology.

Animals↗
PubMed2003

The mouse genome sequence--the end of the tail, or just the beginning?

The recent flurry of papers on the mouse genome includes the description of the full genome assembly, analysis of the mouse transcriptome, the origin of interstrain variation, initial analysis of conserved non-coding regions and high-throughput expression analysis of a subset of genes. Each illustrates how the availability of the genome sequence will change the way mouse biologists do business in future.

Alternative Splicing↗
PubMed2026

Integrated transcriptome analysis and machine learning to construct a homeostatic model of acetylation for bladder cancer and validate the key gene CES1.

BACKGROUND: Bladder cancer (BLCA) is one of the most common malignant tumors of the urinary system. Protein acetylation (PA) plays a critical role in regulating multiple biological processes (BPs), cellular homeostasis, and cancer-related signaling pathways. This study aimed to construct a homeostatic model of acetylation for BLCA using integrated transcriptome analysis and machine learning and to validate the key gene CES1. METHODS: RNA sequencing (RNA-seq) and clinical data were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. Acetylation-related differentially expressed genes (DEGs) in BLCA were screened using differential expression analysis (DEA). An acetylation homeostatic model was constructed via univariate, machine learning-based least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analyses, followed by validation in multiple cohorts. Single-cell RNA-seq analysis was used to explore gene expression patterns in diverse cell types. Enrichment analysis (EA), immune infiltration, and drug sensitivity analysis (DSA) were performed to characterize molecular features of different risk groups. Finally, the biological function of CES1 as the key gene was verified by in vitro knockdown experiments. RESULTS: We established a robust acetylation homeostatic model consisting of five genes, which effectively predicted overall survival (OS) and served as an independent prognostic factor in BLCA. High-risk patients showed significantly poorer prognosis, distinct immune infiltration profiles, and differential drug sensitivity. CES1 was identified and validated as the key gene in this model, which was highly expressed in BLCA and associated with poor prognosis. Knockdown of CES1 markedly suppressed cell proliferation, invasion, and migration, and reduced intracellular coenzyme A (CoA) levels, thereby regulating PA homeostasis. CONCLUSIONS: We developed and validated a novel acetylation homeostatic model for survival stratification and personalized treatment guidance in BLCA, based on integrated transcriptome analysis and machine learning. CES1 is closely associated with intracellular CoA levels and the malignant progression of BLCA. Its potential association with PA homeostasis requires further mechanistic validation, and it may act as a candidate therapeutic biomarker for BLCA.

Bladder cancer (BLCA)↗
PubMed2006

ARED 3.0: the large and diverse AU-rich transcriptome.

A comprehensive search that utilized a large set of mRNA data from human genome databases and additionally, expressed sequence tag (EST) database characterized this latest update of AU-rich elements (AREs) containing mRNA database (ARED). A large number of ARE-mRNA, as much as 4000, were recovered and include many of ARE alternative forms. This number represents as much as 5-8% of the human genes depending on the entire number of genes. The new ARED does not contain only larger and diverse number of ARE-mRNAs but additional functionality and enhanced search capabilities are given in the database website http://rc.kfshrc.edu.sa/ared/. These include class and cluster of AREs, source mRNAs, EST evidence, buildup information, retrieval of lists of genes, and integration with current and new NCBI data, such as Entrez ID and Unigene. Gene Ontology analysis shows there are significant differences in functional diversity of ARED when compared with the overall genome. Many of ARE-genes mediate regulatory processes, reactions to outside stimuli, RNA metabolism, and developmental processes particularly those of early and transient responses. The wide interest in mRNA turnover and importance of AREs in health and disease signify the compilation of ARE-genes.

3' Untranslated Regions↗
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↗
PubMed2005

Pattern profiling and mapping of the fat body transcriptome in Drosophila melanogaster.

In Drosophila, the fat body is a collective name for the masses and sheets of adipose tissue that are distributed throughout the fly body. Thus far, >386,000 Drosophila expressed sequence tags (ESTs) have been deposited to the GenBank database, including 10,443 derived from fat body in flies (data accessed on October 7, 2004). The objective of this study was to map the transcriptome of the fat body in flies and thus provide genomics and bioinformatics tools for developing a Drosophila model for addressing the genetic complexity of obesity in humans. The gene-EST Basic Local Alignment Search Tool (BLAST) matches revealed that these ESTs could represent 12,188 coding genes in the Drosophila genome. Among them, at least 2,261 are expressed in the fat body, including 41 identified as preferentially expressed genes with logarithm of odds >3.0. Self-organizing map analysis revealed a cluster of 290 genes favorably expressed in the fat body compared with genes expressed in five other tissues. Mapping of the fat body transcriptome identified a 1.7-Mb domain on 3L containing 35 genes that were expressed at a much higher level than in other tissues (transcript density factor = 1.0 approximately 2.3).

Animals↗
PubMed2006

Transcriptome analyses of human genes and applications for proteome analyses.

By utilizing recently developed full-length cDNA technologies, large-scale cDNA sequencing was carried out by several cDNA projects. Now full-length cDNA resources cover the major part of the protein-coding human genes. Comprehensive analyses of the collected full-length cDNA data revealed not only the complete sequences of thousands of novel gene transcripts but also novel alternatively spliced isoforms of hitherto identified genes. However, it was not as easy as expected to deduce their encoded amino acid sequences based solely on the full-length cDNA sequences. It was neither always the case that the longest open reading frame corresponded to the real protein coding region nor that the first ATG was the translation initiator codon. Also, proteome-wide mass-spectrometry analysis has shown that there is an unexpectedly large population of small proteins, encoded by so-called upstream open reading frames, within the cell. Since sound manual annotations by experts were still indispensable to address these problems, an international meeting to make transcriptome-wide functional annotations of cDNAs was held, namely the H-invitational. In this meeting, functional annotations were made both manually and computationally for most of the pre-existing full-length cDNAs collected from world-wide cDNA projects. The achieved integrated information for each of the cDNAs was published as a database. It was also shown that the full-length cDNA data were useful for identifying alternative splicing variants, exact transcriptional start sites of the mRNAs and the adjacent promoter regions. Rapidly accumulating genome data as well as versatile use of the transcriptome information will shortly lay a firm foundation for proteome-level understanding of human gene networks.

Alternative Splicing↗
PubMed2003

Non-random distribution of GATC sequences in regions of promoters stimulated by the SeqA protein of Escherichia coli.

The SeqA protein of Escherichia coli is not only the main negative regulator of DNA replication initiation but also a specific transcription factor. It binds to hemimethylated GATC sequences and, with somewhat different specificity, to fully methylated GATC regions. Recently, a microarray analysis was reported, in which transcriptomes of wild-type and DeltaseqA strains were compared. Although in the seqA mutant the levels of some transcripts were significantly decreased while certain transcripts were evidently more abundant relative to wild-type bacteria, no correlation between the presence of GATC motifs in promoter sequences and transcription activity was found. However, here we show that when larger DNA fragments, encompassing positions from -250 to +250 relative to the transcription start site, are analyzed, some common features of GATC distribution near the promoters activated by SeqA can be demonstrated. Nevertheless, it seems that the GATC pattern is not the only determinant of SeqA-dependence of promoter activity.

Bacterial Outer Membrane Proteins↗
PubMed2026

A novel reusable transcriptome-wide association study workflow used to map key genes linked to important cattle traits.

Transcriptome-wide association studies (TWAS) are a powerful approach for studying the genes underlying complex traits by directly integrating GWAS and gene expression datasets. In cattle, they have been previously applied to identify genes driving fertility, milk production, and health. However, these studies have also highlighted several challenges, from difficulties in reproducing these complex analyses to limitations from poor genotype calls, especially when called directly from RNA sequencing data. To address these and other challenges, for the H2020 BovReg Project, we have developed a streamlined, species-agnostic, and reusable Nextflow TWAS workflow to integrate transcriptomic and GWAS summary statistic datasets. Our workflow first generates accurate genotype calls and gene expression prediction models from transcriptomic datasets and then applies these tools to impute gene expression levels into GWAS cohorts, enabling the association of genes with traits of interest. We explore optimal strategies for calling genetic variants directly from transcriptomic data and illustrate that using imputation approaches specifically designed for low-pass sequencing data can improve variant calling over previously adopted methods. We demonstrate the utility of our TWAS workflow by applying it to both novel and publicly available GWAS cohorts for cattle, detecting novel gene-trait associations for complex traits. Using a new transcriptome annotation of the cattle genome generated for the BovReg project we also illustrate how previously un-assayable associations can be detected. The results and the workflow we present, provide a new resource for the community and contribute to a better understanding of the molecular drivers of complex traits in cattle with the goal of eventually leveraging this information in future breeding decisions.

Animals↗
PubMed2026

Exploration and experimental verification of triaptosis-related prognostic genes and cells in gastric cancer.

BACKGROUND: Triaptosis is a recently characterized form of programmed cell death with unclear implications in cancer. This study aimed to investigate the prognostic significance and biological relevance of triaptosis in gastric cancer (GC). METHODS: Transcriptomic and clinical data from TCGA-STAD and GSE62254, and single-cell RNA sequencing data from GSE183904 were analyzed. Triaptosis-related gene (TRG) scores were calculated using single-sample gene set enrichment analysis. Differentially expressed genes identified in TRG-score and GC-versus-normal comparisons underwent functional enrichment, Cox regression, and least absolute shrinkage and selection operator regression to develop an externally validated signature. Immune profiles, pathway activity, somatic mutations, tumor mutational burden (TMB), predicted drug sensitivity, and clinical features were compared by risk group. Single-cell analyses assessed TRG activity, prognostic gene expression, cell-cell communication, and pseudotime. Reverse transcription-quantitative PCR and Western blotting assessed mRNA expression and protein levels, respectively. RESULTS: A TRG-based prognostic model comprising ASPN, GRB14, and VTN was developed and externally validated, effectively distinguishing patients into two distinct risk groups with notably different survival outcomes. mRNA expression of all three genes and their protein levels were significantly higher in SGC-7901 cells than in GES-1 cells. High-risk patients had higher stromal scores and distinct immune profiles; 15 immune cell types differed between groups. Single-cell analysis revealed fibroblasts and pericytes among high-TRG-active cell types. Prognostic genes were significantly overexpressed in fibroblasts, which also showed high TRG activity. Fibroblasts demonstrated enhanced communication with pericytes, whereas tumor-derived fibroblasts showed weaker communication with macrophages, indicating immune microenvironment remodeling. CONCLUSION: The three-gene prognostic signature predicted GC prognosis and was associated with distinct immune and genomic features, suggesting potential value for risk stratification and personalized treatment.

Humans↗
PubMed2006

Identification of pathogenesis-related ESTs in the crucifer downy mildew oomycete Hyaloperonospora parasitica by high-throughput differential display analysis of distinct phenotypic interactions with Brassica oleracea.

Crucifer downy mildew is caused by the obligatory biotrophic oomycete Hyaloperonospora parasitica (formerly Peronospora parasitica). So far, isolates infecting Arabidopsis thaliana have proven to be non-pathogenic on other crucifers and, despite its unequivocal merit as a research model, the pathosystem A. thaliana-H. parasitica by itself will not provide all the answers onto crucifer downy mildew genetics and biology. In this report, we present the development of a differential display (DD)-based strategy, suitable for high-throughput analysis of expressed sequence tags (ESTs) in plant-pathogen interactions, in this work applied to the analysis of the pathosystem Brassica oleracea-H. parasitica interaction transcriptome. Our purpose was the mining for pathogen-specific ESTs that can be used in future research for virulence factors and Avr genes. A total of 743 specific cDNAs showing differential expression in B. oleracea seedlings infected with H. parasitica, as opposed to healthy seedlings, were isolated by DD-PCR. We found 21 exclusively H. parasitica cDNAs from 433 sequenced DD clones, 18 encoding for potential new genes. Our results reinforce the abilities of DD-PCR for differential screening of pathosystems transcriptomes, leading to the finding of more new potential genes than the previously used techniques. Both the improved DD-based methodology and the graphical representations based on Venn diagrams from polyominoes are appropriate for large-scale analysis of multiple interaction transcriptomes. The obtained data are also innovative since this is the first approach to study the interaction of H. parasitica with its natural host.

Base Sequence↗
PubMed2026

Integrating transcriptomics and metabolomics reveals the molecular landscape of sperm maturation driven by regional differentiation in the epididymis of Guizhou-Guiqian semi-fine wool sheep.

Epididymal regionalized differentiation is crucial for sperm maturation. However, little is known about the synergistic remodeling mechanisms of different epididymal segments at the transcriptional and metabolic levels during sexual maturation in ruminants (especially sheep). We investigated the caput, corpus, and cauda epididymidis of pre-pubertal (2-month-old) and post-pubertal (7-month-old) Guizhou-Guiqian semi-fine wool sheep using histology, RNA sequencing, and metabolomics. Post-pubertal tissues exhibited increased luminal diameters, cilia lengths, and abundant cauda spermatozoa. Transcriptomic analysis revealed increasing differentially expressed genes (DEGs) along the caput-corpus-cauda axis (4642, 6103, and 7698 DEGs, respectively). Metabolomics detected 786 unique differentially accumulated metabolites (DAMs). Region-specific analysis showed that in the caput, up-regulated pathways (fructose/mannose metabolism; HK2, ALDOA, HKDC1) provide energy and substrates for initial sperm motility. In the corpus, down-regulated genes associated with extracellular matrix and tight junctions suggested epithelial barrier remodeling to establish an immune-tolerant microenvironment. The cauda specifically up-regulated the pentose phosphate pathway (FBP1, GPI) and glutathione metabolism, maintaining redox homeostasis for long-term sperm storage. Additionally, glycerophospholipid metabolism was enriched across all segments, where PEMT, AGPAT5, and LCAT likely regulate sperm plasma membrane fluidity. In conclusion, during sexual maturation, the caput drives energy metabolism and glycosylation, the corpus establishes immune tolerance, and the cauda maintains antioxidant homeostasis. The glycerophospholipid network throughout the across all epididymal segments synergistically remodels sperm membrane. This study reveals the underlying multi-omics regulatory mechanisms of epididymal functional differentiation, providing a theoretical basis for elucidating the molecular mechanisms of sperm maturation in this breed and for the molecular breeding of early reproductive performance in rams.

Animals↗
PubMed2006

Rampant polyuridylylation of plastid gene transcripts in the dinoflagellate Lingulodinium.

Dinoflagellate plastid genes are believed to be encoded on small generally unigenic plasmid-like minicircles. The minicircle gene complement has reached saturation with an incomplete set of plastid genes (18) compared with typical functional plastids (60-200). While some of the missing plastid genes have recently been found in the nucleus, it is still unknown if additional genes, not located on minicircles, might also contribute to the plastid genome. Sequencing of tailed RNA showed that transcripts derived from the known minicircle genes psbA and atpB contained a homogenous 3' polyuridine tract of 25-40 residues. This unusual modification suggested that random sequencing of a poly(dA) primed cDNA library could be used to characterize the plastid transcriptome. We have recovered only 12 different polyuridylylated transcripts from our library, all of which are encoded on minicircles in several dinoflagellate species. The correspondence of all polyuridylylated transcripts with previously described minicircle genes thus supports the dinoflagellate plastid as harbouring the smallest genome of any functional chloroplast. Interestingly, northern blots indicate that the majority of transcripts are modified, suggesting that polyuridylylation is unlikely to act as a degradation signal as do the heterogeneous poly(A)-rich extensions of transcripts in cyanobacteria and other plastids.

3' Untranslated Regions↗
PubMed2025

Next-generation sequencing in breast cancer: current clinical applications and future directions.

INTRODUCTION: Breast cancer is a heterogeneous disease that claims 670,000 lives by 2022. Omic technologies, particularly next generation sequencing (NGS) offers promising avenues for precision medicine. American Society of Clinical Oncology (ASCO) outlines genomic testing's utility, emphasizing prognostic and diagnostic potential. OBJECTIVES: This review succinctly explores NGS's evolution and clinical applications of NGS in breast cancer, thereby guiding future research to enhance patient care. METHODS: Comprehensive literature searches were conducted using databases such as PubMed, Google Scholar, and ResearchGate, focusing on keywords including breast cancer, HER-2 low breast cancer, circulating tumour DNA, single-cell RNA sequencing, and next-generation sequencing. Peer-reviewed, high-quality articles published in English were selected for inclusion. RESULTS: Previous studies have explored the evolution of NGS technology and its clinical applications in breast cancer, including genomic and transcriptomic characterization, treatment guidance, and resistance prediction. Molecular profiling of challenging entities such as early-onset breast cancer and HER-2 low tumours was summarized, with key findings highlighted. This review also discusses emerging technologies, including circulating DNA and single-cell sequencing, as promising avenues for discovery. CONCLUSION: NGS has revealed the genomic and transcriptomic diversity of breast cancer, identifying actionable alterations associated with chemotherapy response and resistance to therapies such as trastuzumab, TKIs, and CDK4/6 inhibitors. Circulating tumour DNA (ctDNA) shows potential for diagnosis, prediction, prognosis, and monitoring, despite tumour heterogeneity. Single-cell analysis enables exploration of individual cell transcriptomes, though high costs and low throughput remain barriers to widespread adoption. HER2-low tumours continue to pose significant research challenges.

Humans↗