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Comprehensive analysis of DNA methylome and transcriptome reveals the epigenetic regulation of nitric oxide treatment in delaying apricot fruit senescence.

Apricot produces climacteric fruit, which are perishable after harvest. To elucidate the regulatory role of NO treatment through DNA methylation in post-harvest senescence, apricot fruits were treated with 0.2 mmol/L sodium nitroprusside (SNP) solution for 10 min, with distilled water treatment serving as the control. Treated fruits were then stored at 25°C and 80% relative humidity. Changes in appearance quality, physiological parameters, metabolome profiles, transcriptome dynamics, and DNA methylation patterns were analyzed before and after storage. Results showed that NO treatment delayed apricot softening, increased flavonoid metabolite accumulation, and reduced lipid and abscisic acid accumulation, with these effects correlated to the expression of specific genes and transcription factors. This work reveals the epigenetic regulatory mechanism underlying NO treatment delaying ripening and senescence. Further analysis revealed that the transcription levels of ACO, PAL, UFGT-like, NCED1, PP2C, MYB21, CCoAOMT-like, CYP707A, and ZNF7-like were all correlated with DNA methylation. This indicates that SNP treatment can lead to large changes in DNA methylation levels in apricot fruits, and that the differences in gene transcription levels are associated with the occurrence of hypomethylation and hypermethylation. Collectively, these findings establish an epigenetic framework for post-harvest regulation of apricot fruit, revealing DNA methylation-mediated freshness preservation mechanisms.

DNA Methylation↗

Targeting USP22 reprograms the tumor microenvironment and sensitizes KRAS/p53-driven lung cancer to anti-PD-1 immunotherapy.

RATIONALE: Ubiquitin-specific peptidase 22 (USP22), a deubiquitinase and component of the "Death-from-Cancer" 11-gene signature, is overexpressed in multiple malignancies and linked to recurrence, therapy resistance, and poor prognosis. Its role in KRAS/p53-driven lung cancer and the response to immune checkpoint inhibitors (ICIs) remains poorly defined. Here, we investigated USP22 as a potential therapeutic target in KRAS/p53-driven lung cancer. METHODS: A conditional Usp22 knockout (Usp22-KO) was generated in the KRASG12D; p53-/- (KP) mouse model. Cancer progression was monitored by micro-computed tomography (micro-CT). Multiplex immunofluorescence (mIF), RNA sequencing, and spatial transcriptomics profiled cancer and tumor microenvironment (TME) changes. Responses to anti-PD-1/PD-L1 therapies were compared between KP and Usp22-KO KP (KPU-) lung cancers. RESULTS: USP22 was highly expressed in early-stage KRAS/p53-driven mouse lung cancers and strongly correlated with proliferation marker Ki67. Usp22 deletion suppressed cancer growth, prolonged survival, and promoted cancer differentiation. Spatial transcriptomics and mIF revealed reduced CD206+ M2 macrophages, myeloid-derived suppressor cells (MDSCs), TGF-β1, and angiogenesis, along with increased functional CD8+ T cells. Mechanistically, USP22 regulated gene expression and protein stability, reducing c-Myc, PD-L1, TGF-β1, and SPARC upon Usp22 loss. Compared with KP cancer, KPU- and SPARC-knockdown KP cancers showed reduced macrophage chemotaxis and impaired basal- and TGF-β1-induced M2 polarization of RAW264.7 cells, suggesting that TGF-β1 and SPARC downregulation partially contributes to decreased M2 macrophage infiltration in KPU- cancers. Notably, Usp22 loss enhanced the efficacy of anti-PD-L1 and anti-PD-1 therapies in orthotopic and subcutaneous KP lung cancer models, respectively. USP22 and SPARC expression were also strongly correlated in human lung cancers. CONCLUSIONS: USP22 promotes progression and immune evasion in KRAS/p53-driven lung cancer. Targeting USP22 reprograms the TME, suppresses oncogenic signaling, and sensitizes tumors to ICI, establishing USP22 as a promising therapeutic target.

Animals↗

Genome-wide analysis of the expression profile of Saccharomyces cerevisiae in response to treatment with the plant isoflavone, wighteone, as a potential antifungal agent.

The limitations of currently available antifungal agents and the rapid emergence of drug-resistant strains necessitate more efficient approaches to screening and developing novel antifungal drugs. The antifungal activity of the natural products of a series of plants was evaluated and wighteone, 5, 7, 4'-trihydroxy-6-(gamma,gamma-dimethylallyl)isoflavone showed excellent anti-yeast activity (MIC against Saccharomyces cerevisiae was 4 microg/ml). Transcriptome profiling of wighteone-treated S. cerevisiae indicated that wighteone is different from commonly used antifungal compounds in its mode of action.

Antifungal Agents↗

Genome-wide identification of WOX transcription factors and functional characterization of WOX4 and WOX13 involved in cold stress response in Malus baccata.

INTRODUCTION: Cold stress is a major abiotic threat to apple production. Malus baccata has exceptional cold hardiness and is widely used as a superior cold-resistant rootstock. The WUSCHEL-related homeobox (WOX) transcription factor family regulates plant growth, development and stress adaptation, whereas the functions of WOX genes in cold tolerance of M. baccata remain elusive. METHODS: In the present work, 19 MbWOX family members were identified and characterized at the genome-wide level. Evolutionary analysis, cis-element prediction, transcriptome profiling and real-time quantitative PCR (RT-qPCR) were performed to screen core cold-responsive genes. Overexpression vectors were constructed and transformed into Arabidopsis seedlings for functional verification. RESULTS: Evolutionary analysis revealed that segmental duplication drove the expansion of the MbWOX family, and these genes contained a variety of stress-responsive cis-elements. Combined transcriptome and RT-qPCR analyses confirmed that MbWOX4 and MbWOX13 were core cold-responsive genes with distinct expression patterns. The two genes participated in cold signal transduction by interacting with different transcription factor networks. Functional tests revealed that MbWOX4 and MbWOX13 isoforms differentially modulated seedling cold tolerance under low-temperature stress.

Malus baccata↗

Responses of the Rhodobacter sphaeroides transcriptome to blue light under semiaerobic conditions.

Exposure to blue light of the facultative phototrophic proteobacterium Rhodobacter sphaeroides grown semiaerobically results in repression of the puc and puf operons involved in photosystem formation. To reveal the genome-wide effects of blue light on gene expression and the underlying photosensory mechanisms, transcriptome profiles of R. sphaeroides during blue-light irradiation (for 5 to 135 min) were analyzed. Expression of most photosystem genes was repressed upon irradiation. Downregulation of photosystem development may be used to prevent photooxidative damage occurring when the photosystem, oxygen, and high-intensity light are present simultaneously. The photoreceptor of the BLUF-domain family, AppA, which belongs to the AppA-PpsR antirepressor-repressor system, is essential for maintenance of repression upon prolonged irradiation (S. Braatsch et al., Mol. Microbiol. 45:827-836, 2002). Transcriptome data suggest that the onset of repression is also mediated by the AppA-PpsR system, albeit via an apparently different sensory mechanism. Expression of several genes, whose products may participate in photooxidative damage defense, including deoxypyrimidine photolyase, glutathione peroxidase, and quinol oxidoreductases, was increased. Among the genes upregulated were genes encoding two sigma factors: sigmaE and sigma38. The consensus promoter sequences for these sigma factors were predicted in the upstream sequences of numerous upregulated genes, suggesting that coordinated action of sigmaE and sigma38 is responsible for the upregulation. Based on the dynamics of upregulation, the anti-sigmaE factor ChrR or its putative upstream partner is proposed to be the primary sensor. The identified transcriptome responses provided a framework for deciphering blue-light-dependent signal transduction pathways in R. sphaeroides.

Bacterial Proteins↗

Sperm-induced modification of the oviductal gene expression profile after natural insemination in mice.

In mammals, the physiological interaction between spermatozoa and oviductal epithelia involves intimate and specific contact between the two cell types. Spermatozoa may undergo stringent selection processes within the female reproductive tract before they meet and fertilize oocytes. The physiological basis of the sperm selection process is largely unknown. Here we tested the hypothesis that the oviduct has a recognition system for spermatozoa that can detect the arrival of spermatozoa in the oviduct after insemination, resulting in alterations of the oviductal transcriptome. We initially performed a global screening of the oviductal transcriptome in mice 1) at the time of estrus (mating) and 2) 6 h after mating. Transcriptional alterations in the oviduct after mating were attributed to the presence of spermatozoa in the oviduct after mating and also to changes in the hormonal environment as female mice underwent the transition from estrus to diestrus. To distinguish these possibilities, female mice were then mated with T145H mutant mice, which because of spermatogenic arrest, produce seminal plasma but no spermatozoa. Focusing on two molecules that in the first experiment were upregulated after mating, it was found that adrenomedullin and prostaglandin endoperoxidase synthase 2 transcripts were upregulated in the oviducts of mice only after mating with fertile males; those mated with T145H infertile males showed significantly less response. These results indicate that it is the arrival of spermatozoa in the oviduct that activates one or more signal transduction pathways and leads to changes in the oviductal transcriptome profiles.

Adrenomedullin↗

Single-nucleus transcriptomics reveals cell type-specific remodeling and epilepsy-associated microglia.

Temporal lobe epilepsy (TLE) is the most common acquired epilepsy, causing refractory seizures and cognitive deficits. We performed single-nucleus RNA sequencing on hippocampal tissue from mice 3 and 6 weeks following pilocarpine-induced status epilepticus, a robust model of TLE. Epilepsy samples showed reductions in Cck and Lamp5-Lhx6 interneuron subclusters, alongside increases in Cajal-Retzius cells, dentate granule (DG) cell precursors, and a mature DG cell subcluster. Among glia, an astrocyte subcluster and a markedly expanded microglia sublcuster were increased. We term this microglia population epilepsy-associated microglia (EAM). The transcriptomic profile of EAM overlaps with microglia described in models of Alzheimer's disease and traumatic brain injury, including enrichment of Myo1e and Igf1. EAM display amoeboid morphology, can be found in clumps around pyramidal and granule cell body layers, and exhibit enlarged vesicles and mitochondria. Cell-cell interaction analysis predicts DG cells as their primary interaction partners. This dataset defines transcriptomic programs underlying key cellular alterations in TLE, enabling mechanistic dissection of epileptogenesis.

TLE↗

Transcriptional profiling of the human monocyte-to-macrophage differentiation and polarization: new molecules and patterns of gene expression.

Comprehensive analysis of the gene expression profiles associated with human monocyte-to-macrophage differentiation and polarization toward M1 or M2 phenotypes led to the following main results: 1) M-CSF-driven monocyte-to-macrophage differentiation is associated with activation of cell cycle genes, substantiating the underestimated proliferation potential of monocytes. 2) M-CSF leads to expression of a substantial part of the M2 transcriptome, suggesting that under homeostatic conditions a default shift toward M2 occurs. 3) Modulation of genes involved in metabolic activities is a prominent feature of macrophage differentiation and polarization. 4) Lipid metabolism is a main category of modulated transcripts, with expected up-regulation of cyclo-oxygenase 2 in M1 cells and unexpected cyclo-oxygenase 1 up-regulation in M2 cells. 5) Each step is characterized by a different repertoire of G protein-coupled receptors, with five nucleotide receptors as novel M2-associated genes. 6) The chemokinome of polarized macrophages is profoundly diverse and new differentially expressed chemokines are reported. Thus, transcriptome profiling reveals novel molecules and signatures associated with human monocyte-to-macrophage differentiation and polarized activation which may represent candidate targets in pathophysiology.

Cell Differentiation↗

Analysis of organ-specific, expressed genes in Oncidium orchid by subtractive expressed sequence tags library.

The pseudobulb of Oncidium orchid plays a key role in water, carbohydrate, and other nutrition support during floral development, yet a large scale of gene expression analysis involved in the metabolisms have not been evaluated. By subtracting RsaI-digested cDNAs of leaf from those of psuedobulb, an efficient subtractive cDNA library was developed. In total, 1080 subtractive expressed sequence tags (ESTs) were obtained. Analysis revealed approximately 636 unique gene parts, 120 clusters and 516 singles. Of these sequences, 74.8% were annotated on the database of NCBI GenBank. Peroxidase, sodium/dicarboxylate cotransporter, and mannose-binding lectin were highly expressed. Some gene profiles were identified as related to carbohydrate metabolism involved in mannan, pectin, starch and sucrose biosynthesis. A large fraction of the ESTs (35%) were classified into transportation, stress-related, cell cycle, or regulatory functions. Most genes that were differentially expressed are important in early flowering development, carbohydrate metabolism and stress-response physiology. This efficient organ-specific EST library represented an explicit transcriptome profile of Oncidium pseudobulb.

Base Sequence↗

Transcriptome differences between the frontal cortex and hippocampus of wild-type and humanized presenilin-1 transgenic mice.

OBJECTIVE: The authors investigated the differences between the frontal cortical (Fc) and hippocampal (Hc) transcriptomes of wild type (wt mPS1), humanized presenilin-1 (PS1 [wt hPS1]) and Alzheimer-disease (AD)-linked DeltaE9 hPS1 mutant mice. METHODS: Using high-density oligonucleotide arrays, they recently performed transcriptome profiling of wt mPS1, wt hPS1, and DeltaE9 hPS1 mutant mice. Whereas these studies analyzed the commonalities of gene expression patterns and commonly-regulated genes across the two brain areas and across the animal models, the current study focused on the gene-expression differences across Fc and Hc, two critical AD-affected brain regions. RESULTS: The data revealed that in the wild-type mice, there are significant transcriptome differences between the Fc and the Hc tissue, and these expression differences are maintained in humanized transgenic mice carrying the wt hPS1 gene or DeltaE9 hPS1 mutation. Also, they provide evidence that a subset of genes show disturbed regional Fc-Hc gene-expression ratios in the transgenic mice carrying the DeltaE9 hPS1 mutation. Some of these genes, including stearoyl-Coenzyme A desaturase-2 (Scd2) and Prostaglandin D2 synthase (Ptgds), have been previously implicated in the pathology of AD. CONCLUSIONS: Data suggest that disturbed gene-expression ratios between cortical regions may be an important event in altered brain physiology.

Alzheimer Disease↗

Oncogenic PIK3CA reprograms glutamine metabolism to drive bladder cancer progression.

BACKGROUND: Genomic analysis has revealed that approximately 40% of bladder cancer (BLCA) tumors harbor alterations in the PI3K/AKT pathway, with PIK3CA mutations occurring in 15-25% of cases. PIK3CA, which encodes the catalytic p110α subunit of PI3K, plays a critical role in regulating cell survival, proliferation, and metabolism. However, the metabolic and functional consequences of PIK3CA mutations in BLCA remain poorly defined. METHODS: To investigate the role of PIK3CA mutations in BLCA, we performed targeted sequencing on tumors from patients, identifying recurrent alterations. Using CRISPR/Cas9 knock-in models in SCaBER and UM-UC-3 cell lines, we introduced the PIK3CA E545K mutation to study its effects. We conducted transcriptomic profiling, targeted metabolomics, and stable isotope tracing to assess metabolic reprogramming. Functional assays measured proliferation, mitochondrial complex I activity, and glutaminolysis. Orthotopic xenografts in mice were used to evaluate in vivo tumor growth and metabolism. RESULTS: PIK3CA mutations were present in 20% of cases, consistent with TCGA data. The E545K and E545Q hotspots accounted for 70% of these mutations. PIK3CA E545K strongly activated PI3K/AKT signaling. Transcriptomic analysis revealed enrichment of OXPHOS, fatty acid metabolism, and mTORC1 signaling. Metabolomics indicated changes in TCA cycle metabolites and enhanced reductive carboxylation of glutamine to citrate, driving fatty acid synthesis. Mutant cells showed increased expression of GLS1 and FASN, higher proliferation rates, and elevated mitochondrial complex I activity. In vivo, PIK3CA-mutant xenografts displayed significantly increased tumor growth. CONCLUSION: PIK3CA mutations are frequent drivers of metabolic reprogramming in BLCA, leading to increased glutamine flux, elevated OXPHOS activity, and enhanced fatty acid synthesis, all of which contribute to tumor progression. These findings provide the first comprehensive evidence that PIK3CA-driven metabolic alterations are both biomarkers of aggressive disease and actionable therapeutic targets. The efficacy of PI3Kα inhibition in combination with metabolic targets may support its potential in precision medicine for PIK3CA-mutant BLCA and highlights the value of integrating metabolic biomarkers into treatment strategies for advanced BLCA.

Journal Article↗

Probiotic Lacticaseibacillus casei 2S-1 Attenuates Escherichia coli-Induced Enteritis via Gut Microbiota Modulation and Host Gene Regulation.

Maintaining gut microbial homeostasis is crucial for host health, whereas infection with Escherichia coli (E. coli) is a major contributor to intestinal inflammation and microbial dysbiosis. Recent research has focused on probiotic strategies for managing enteric inflammatory disorders. Previous studies have shown that beneficial microorganisms show protection through modulating host immune responses, enhancing intestinal epithelial barrier integrity, and inhibiting pathogenic bacteria. To evaluate the prophylactic effectiveness of a recently isolated strain, Lacticaseibacillus casei 2S-1, in a murine model of E. coli-induced enteritis, this study focuses on interactions within the microbiota-intestinal-immune axis, together with host transcriptional responses and pathway enrichment associated with oxidative stress and mitochondrial function. In vitro analysis of probiotic features, including growth dynamics, acidogenic capacity, and tolerance to acidic and bile salt environments, as well as genetic safety profiling, followed the methodical isolation and taxonomic identification of L. casei 2S-1. A preventive intervention protocol was established, and a murine model of enteritis was induced by exposure to E. coli. Histopathological analyses were performed to observe in vivo safety and protective efficacy. Changes in gut microbial structure were characterized by 16S rRNA gene sequencing, while host responses were identified by intestinal immunohistochemistry and transcriptome profiling. L. casei 2S-1 showed probiotic properties. In vitro analyses showed that the strain exhibited tolerance to acidic and bile salt conditions, and its untreated culture supernatant showed antimicrobial activity against pathogenic bacteria. Its safety profile was supported by genomic analysis, which verified the lack of virulence-associated genes and antibiotic resistance factors. In vivo, L. casei 2S-1 pretreatment reduced mortality and intestinal inflammation, modulated gut microbial composition, and preserved intestinal barrier-associated protein expression in infected mice. This study provides experimental evidence supporting the prophylactic effects of L. casei 2S-1 and its associations with gut microbiota modulation and host transcriptional responses, providing a foundation for further investigation of probiotic-based preventive strategies against intestinal infections.

Animals↗

Prognostic and immunological implications of sialylation-associated gene signatures in hepatocellular carcinoma.

OBJECTIVE: The absence of effective biomarkers continues to limit early diagnostic accuracy and prognostic evaluation in patients with hepatocellular carcinoma (HCC). Aberrant sialylation (SI) has been demonstrated to contribute to therapeutic resistance and tumor progression. The aim of this investigation was to identify a sialylation-related gene (SRG) signature, evaluate its prognostic significance, and investigate associated immunological characteristics in HCC. METHODS: Transcriptomic profiles and corresponding clinical data for patients with HCC were obtained from UCSC Xena, the International Cancer Genome Consortium (ICGC), and the Molecular Signatures Database (MsigDB). Differential expression analysis, Cox regression analysis modeling, and least absolute shrinkage and selection operator (LASSO) regression analysis were applied to identify independent prognostic markers and develop predictive models. The tumor immune microenvironment and its relationship with the identified SRGs were assessed by evaluating immune infiltration patterns. A gene co-expression network for the prognostic SRGs was constructed using GeneMANIA to identify potentially targetable signaling pathways. RESULTS: Four SRGs (ST6GALNAC4, B4GALT5, B4GALNT1, and NEU1) were significantly associated with the prognosis of patients with HCC. Prognostic models constructed using these genes demonstrated strong predictive performance. Notable differences were observed in immune cell populations and immune checkpoint expression between the high-risk and low-risk groups. Additionally, the half-maximal inhibitory concentration values for 101 therapeutic compounds varied between these groups. Lipopolysaccharide and sphingolipid metabolism were identified as key biological processes linked to tumor progression and modulation of the immune microenvironment. CONCLUSION: The four identified SRGs were significantly associated with clinical outcomes and immunological features in HCC. These findings provide a foundation for advancing early diagnostic strategies, refining prognostic assessments, and guiding personalized therapeutic approaches for patients with HCC.

Humans↗

Proteomics in nutrition research: principles, technologies and applications.

The global profiling of the whole protein complement of the genome expressed in a particular cell or organ, or in plasma or serum, makes it possible to identify biomarkers that respond to alterations in diet or to treatment, and that may have predictive value for the modelling of biological processes. Proteomics has not yet been applied on a large scale in nutritional studies, yet it has advantages over transcriptome profiling techniques in that it directly assesses the entities that carry out the biological functions. The present review summarizes the different approaches in proteomics research, with special emphasis on the current technical 'workhorses': two-dimensional (2D)-PAGE with immobilized pH gradients and protein identification by MS. Using a work-flow approach, we provide information and advice on sample handling and preparation, protein solubilization and pre-fractionation, protein separation by 2D-PAGE, detection and quantification via computer-assisted analysis of gels, and protein identification and characterization techniques by means of MS. Examples from nutritional studies employing proteomics are provided to demonstrate not only the advantages but also the limitations of current proteome analysis platforms.

Electrophoresis, Gel, Two-Dimensional↗

Genome-Wide Characterization of the ZIP Transporter Family in Sea Island Cotton (Gossypium barbadense L.) and Expression Profiling Under Heavy Metal and Pathogen Stresses.

G. barbadense represents an indispensable germplasm resource for high-quality textile fiber and disease resistance; nevertheless, systematic information regarding its ZRT/IRT-like protein (ZIP) gene family remains limited. Here, a total of 46 GbZIP genes were identified across the G. barbadense genome. Comprehensive bioinformatic investigations revealed uneven chromosomal distribution and confirmed that segmental/whole-genome duplications, supplemented by localized tandem duplications, drove family expansion. Members clustered within the same phylogenetic clades shared conserved motif organization and gene architecture, while promoter regions harbored abundant cis-acting elements associated with phytohormone and stress signaling. Transcriptome profiling indicated distinct expression patterns across vegetative/reproductive tissues, fiber and ovule developmental stages, and diverse abiotic stress conditions (cold, hot, drought, and salt). Quantitative Real-Time PCR (qRT-PCR) further validated that several GbZIP candidates exhibited temporal expression variations upon exposure to cadmium toxicity, V. dahliae infection, and combined Cd-V. dahliae stress. Specifically, GbZIP13, GbZIP18, GbZIP27, and GbZIP36 displayed prominent broad-spectrum responses to all three stress conditions, whereas GbZIP16, GbZIP29, and GbZIP30 showed stress-specific regulatory divergence. Overall, this study aims to systematically analyze the evolutionary characteristics and expression patterns of the GbZIP family, and to specifically evaluate the response differences under Cd stress, V. dahliae stress, and combined stress, in order to identify potential key candidate genes.

Gossypium barbadense↗

Gene expression profiles of primary colorectal carcinomas, liver metastases, and carcinomatoses.

BACKGROUND: Despite the fact that metastases are the leading cause of colorectal cancer deaths, little is known about the underlying molecular changes in these advanced disease stages. Few have studied the overall gene expression levels in metastases from colorectal carcinomas, and so far, none has investigated the peritoneal carcinomatoses by use of DNA microarrays. Therefore, the aim of the present study is to investigate and compare the gene expression patterns of primary carcinomas (n = 18), liver metastases (n = 4), and carcinomatoses (n = 4), relative to normal samples from the large bowel. RESULTS: Transcriptome profiles of colorectal cancer metastases independent of tumor site, as well as separate profiles associated with primary carcinomas, liver metastases, or peritoneal carcinomatoses, were assessed by use of Bayesian statistics. Gains of chromosome arm 5p are common in peritoneal carcinomatoses and several candidate genes (including PTGER4, SKP2, and ZNF622) mapping to this region were overexpressed in the tumors. Expression signatures stratified on TP53 mutation status were identified across all tumors regardless of stage. Furthermore, the gene expression levels for the in vivo tumors were compared with an in vitro model consisting of cell lines representing all three tumor stages established from one patient. CONCLUSION: By statistical analysis of gene expression data from primary colorectal carcinomas, liver metastases, and carcinomatoses, we are able to identify genetic patterns associated with the different stages of tumorigenesis.

Carcinoma↗

Rhodopseudomonas palustris CGA009 has two functional ppsR genes, each of which encodes a repressor of photosynthesis gene expression.

The PpsR protein is a regulator of redox-dependent photosystem development in purple phototrophic bacteria. In contrast to most species, Rhodopseudomonas palustris contains two ppsR genes. We show that the inactivation of each of the R. palustris strain CGA009 ppsR genes results in an elevated level of formation of the photosystem under dark aerobic conditions. Absorption spectra of the two PpsR mutants revealed qualitative and quantitative differences in light-harvesting peak amplitude increases. A sequence difference in the helix-turn-helix DNA binding motif of PpsR2 (Arg 439 to Cys) between R. palustris strains CEA001 and CGA009 is shown to be a natural polymorphism that does not inactivate the repressor activity of the protein. To evaluate which photosynthesis genes are regulated by the two PpsR proteins, transcriptome profiles of the CGA009 and PpsR mutant strains were analyzed in microarray experiments. Transcription of most but not all photosystem genes was derepressed in the mutant strains to levels consistent with the in vivo absorption spectra, mathematical analyses of peak shapes and amplitudes, reaction center protein levels, and real-time PCR of selected mRNAs. Closely spaced PpsR binding motif repeats were identified 5' of genes that were derepressed in the transcriptome analysis of PpsR mutants. This work shows that both the PpsR1 and PpsR2 proteins from R. palustris strain CGA009 function as oxygen-responsive transcriptional repressors.

Aerobiosis↗

Genomic and molecular landscape of early onset colorectal cancer: Emerging insights and clinical implications-A systematic review.

BACKGROUND: Early onset colorectal cancer, defined as colorectal malignancy occurring before age 50, has been rising globally. Increasing molecular evidence suggests that early onset colorectal cancer is not merely a premature form of late-onset colorectal cancer but a distinct biologic entity with unique genomic and transcriptomic profiles. METHODS: A systematic PubMed search using the terms "early onset colorectal cancer," "genomic," and "molecular" identified 270 records. Eighteen original studies met the inclusion criteria and were supplemented by references from selected articles. Extracted data encompassed clinicopathologic characteristics, genomic and epigenetic alterations, and dysregulated signaling pathways distinguishing early onset colorectal cancer from late-onset colorectal cancer. RESULTS: Evidence from approximately 19,888 patients with early onset colorectal cancer was synthesized across genomic, transcriptomic, and clinical data sets. Early onset colorectal cancer showed a predominance in distal and rectal sites, a slight male bias, and a higher prevalence among Hispanic and Asian populations. Compared with late-onset colorectal cancer, early onset colorectal cancer exhibited lower B-Raf proto-oncogene, serine/threonine kinase V600E mutation and CpG island methylator phenotype-high methylation frequencies but higher rates of tumor protein p53, Kirsten rat sarcoma viral oncogene homolog, and DNA-repair gene alterations. Distinct comutation patterns (F-box and WD repeat domain containing 7-neurogenic locus notch homolog protein 3-phosphoinositide-3-kinase regulatory subunit 1 and adenomatous polyposis coli-tumor protein p53) and overexpression of immediate-early response genes (Proto-Oncogene c-Fos, EGR1, DUSP1, and CYR61) defined its transcriptional landscape. Perturbations of Wingless/Integrated signaling pathway, mitogen-activated protein kinase, phosphoinositide 3-kinase-protein kinase B-mechanistic target of rapamycin, and DNA-repair pathways, along with global long interspersed nuclear element-1 hypomethylation, indicated heightened genomic instability. CONCLUSION: Early onset colorectal cancer develops through tumor protein p53-driven genomic instability and defective DNA repair rather than the canonical CpG island methylator phenotype-B-Raf proto-oncogene, serine/threonine kinase axis. Recognition of these molecular distinctions is essential for age-specific risk assessment, screening, and precision therapeutics. Further integrative studies are needed to elucidate environmental and genetic contributors and identify novel biomarkers and treatment targets.

Humans↗