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Transcriptome-based high-frequency recurrence index predicts frequent recurrence in non-muscle-invasive bladder cancer after Bacillus Calmette-Guérin therapy.

BACKGROUND: High-frequency recurrence (HfR,&#x2009;&#x2265;&#x2009;2 recurrences) in non-muscle-invasive bladder cancer (NMIBC) poses a significant clinical burden. Current risk models, such as the European Organization for Research and Treatment of Cancer (EORTC), the European Association of Urology (EAU), and the UROMOL classification, offer limited predictive accuracy for identifying patients at risk for frequent recurrence despite appropriate treatment. METHODS: A 75-gene high-frequency recurrence index (HfRI) was constructed by selecting recurrence-associated genes using differential expression and Cox regression analyses. The HfRI was computed as a weighted sum of normalized gene expression values. The model was trained on a discovery cohort and validated in multiple cohorts (n&#x2009;=&#x2009;1379) using machine-learning approaches. Clinical relevance was assessed using recurrence-free survival (RFS) and Cox models, and predictive performance was compared with that of the EORTC, EAU, and UROMOL classifications using the area under the curve (AUC) and the concordance index (c-index). RESULTS: The HfRI robustly stratified patients into high-risk and low-risk groups across six independent NMIBC cohorts. Patients classified as HfRI-high had a significantly greater likelihood of experiencing&#x2009;&#x2265;&#x2009;2 recurrences (&#x3c7;2, p&#x2009;=&#x2009;0.001) and showed markedly reduced RFS (log-rank test, p&#x2009;<&#x2009;0.001). The adverse prognostic effect of the HfRI persisted even among patients treated with BCG therapy (log-rank test, p&#x2009;=&#x2009;0.02). Multivariate analysis revealed that the HfRI was an independent predictor of HfR (HR&#x2009;=&#x2009;2.82, 95% CI&#x2009;=&#x2009;1.89-4.20, p&#x2009;<&#x2009;0.001). Compared with established clinical risk classifiers, the HfRI demonstrated superior predictive performance (AUC&#x2009;=&#x2009;0.736, c-index&#x2009;=&#x2009;0.673) in terms of the EORTC (AUC&#x2009;=&#x2009;0.594), EAU (AUC&#x2009;=&#x2009;0.557) risk groups, and UROMOL2021 (AUC&#x2009;=&#x2009;0.596) classification. Pathway analysis revealed that HfRI-high tumors were characterized by upregulation of cell cycle progression and DNA replication pathways, accompanied by suppression of immune signaling pathways. These biological features provide a mechanistic explanation for the reduced responsiveness to intravesical BCG therapy, underscoring the role of HfRI not only as a predictor of recurrence risk but also as a biomarker capable of identifying patients unlikely to benefit from standard BCG treatment. CONCLUSIONS: HfRI represents a robust, transcriptome-based tool for predicting frequent recurrence in NMIBC patients. The HfRI supports earlier identification of patients at risk of high-frequency recurrence, thereby supporting personalized treatment strategies.

Humans↗

Dynamic architecture of the yeast cell cycle uncovered by wavelet decomposition of expression microarray data.

Wavelet analysis has been applied to yeast cell cycle expression microchip data to reveal large-scale temporal structures and ubiquitous oscillations in mRNA levels. Discrete intervals in time within the cell cycle when expression levels changed were visualized as contour maps in which points of transition in gene expression among all 6178 genes were plotted as a function of cell cycle time. Time-frequency analysis using wavelet transforms supported the direct visualization and led to the conclusion that the predominant period is not the cell cycle but a higher frequency, 40 min, submultiple of the cycle. Each of the 6178 gene expression profiles was dissected by wavelet decomposition into all permitted frequencies from the Nyquist limit to roughly twice the cell cycle length. Transitions associated with maximum up- or down-regulation of mRNA levels appear as bands at circa 40-min intervals, half the length of the cycle, through two cell cycles. More than two thirds of the genes, including many of the cyclins, showed this half-cycle periodicity. Gene expression and events within the yeast cell cycle may be regulated by an attractor whose fundamental period is an emergent property of dynamic interactions within the yeast transcriptome.

Cell Cycle↗

Comprehensive analyses of prostate gene expression: convergence of expressed sequence tag databases, transcript profiling and proteomics.

Several methods have been developed for the comprehensive analysis of gene expression in complex biological systems. Generally these procedures assess either a portion of the cellular transcriptome or a portion of the cellular proteome. Each approach has distinct conceptual and methodological advantages and disadvantages. We have investigated the application of both methods to characterize the gene expression pathway mediated by androgens and the androgen receptor in prostate cancer cells. This pathway is of critical importance for the development and progression of prostate cancer. Of clinical importance, modulation of androgens remains the mainstay of treatment for patients with advanced disease. To facilitate global gene expression studies we have first sought to define the prostate transcriptome by assembling and annotating prostate-derived expressed sequence tags (ESTs). A total of 55000 prostate ESTs were assembled into a set of 15953 clusters putatively representing 15953 distinct transcripts. These clusters were used to construct cDNA microarrays suitable for examining the androgen-response pathway at the level of transcription. The expression of 20 genes was found to be induced by androgens. This cohort included known androgen-regulated genes such as prostate-specific antigen (PSA) and several novel complementary DNAs (cDNAs). Protein expression profiles of androgen-stimulated prostate cancer cells were generated by two-dimensional electrophoresis (2-DE). Mass spectrometric analysis of androgen-regulated proteins in these cells identified the metastasis-suppressor gene NDKA/nm23, a finding that may explain a marked reduction in metastatic potential when these cells express a functional androgen receptor pathway.

DNA, Complementary↗

Continued discovery of transcriptional units expressed in cells of the mouse mononuclear phagocyte lineage.

The current RIKEN transcript set represents a significant proportion of the mouse transcriptome but transcripts expressed in the innate and acquired immune systems are poorly represented. In the present study we have assessed the complexity of the transcriptome expressed in mouse macrophages before and after treatment with lipopolysaccharide, a global regulator of macrophage gene expression, using existing RIKEN 19K arrays. By comparison to array profiles of other cells and tissues, we identify a large set of macrophage-enriched genes, many of which have obvious functions in endocytosis and phagocytosis. In addition, a significant number of LPS-inducible genes were identified. The data suggest that macrophages are a complex source of mRNA for transcriptome studies. To assess complexity and identify additional macrophage expressed genes, cDNA libraries were created from purified populations of macrophage and dendritic cells, a functionally related cell type. Sequence analysis revealed a high incidence of novel mRNAs within these cDNA libraries. These studies provide insights into the depths of transcriptional complexity still untapped amongst products of inducible genes, and identify macrophage and dendritic cell populations as a starting point for sampling the inducible mammalian transcriptome.

Animals↗

Single-cell capture of on-ART SIV transcription reveals TGF-&#x3b2;-mediated metabolic control of viral latency.

We previously demonstrated that blocking TGF-&#x3b2; with galunisertib, a safe, orally available small drug, reactivated latent SIV in vivo by shifting T cells toward a transitional effector phenotype. Here, we investigated the mechanisms underlying this effect using single-cell RNA sequencing, metabolic profiling, and high-dimensional spectral flow cytometry of samples from SIV-infected, antiretroviral therapy-treated (ART-treated) macaques before and after galunisertib. To characterize virus-transcribing, infected cells during ART, we developed a novel, sensitive SIV Transcripts Capture Assay (SCAP) that detected 127 SIV-expressing cells within lymph node single-cell transcriptome libraries. Galunisertib drove broad metabolic reprogramming in CD4+ T cells, with transcriptional upregulation of inflammatory and mitochondrial biosynthesis pathways, confirmed by Seahorse profiling. Metabolomics revealed increased energy metabolites and amino acids and enhanced metabolic flux without proliferation. SIV transcript-positive cells before galunisertib were metabolically quiescent compared with cells without detectable viral transcripts. After galunisertib, virus-expressing cells showed a dramatic metabolic activation, with upregulation of glycolysis, fatty acid metabolism, and TNF-&#x3b1; signaling. High-dimensional flow cytometry demonstrated effects beyond CD4+ T cells, including fewer tissue-resident memory T cells, but more inflammatory macrophages. In conclusion, SCAP represents a specific tool for characterizing rare SIV-infected cells transcribing virus during ART, and it reveals TGF-&#x3b2; as a key mediator of viral latency in vivo through metabolic suppression.

Virus Latency↗

Integrating GWAS and Transcriptome Analysis Identifies Candidate Genes for Kernel Starch Quality Traits in Maize.

Maize (Zea mays L.) starch quality is a complex trait with significant implications for grain processing and industrial applications. However, the genetic basis underlying starch quality, particularly for gelatinization and thermodynamic properties, remains poorly understood. In this study, we evaluated 12 starch quality traits, including seven gelatinization characteristics, four thermodynamic traits, and kernel starch content (KSC) in a diverse panel of 335 maize inbred lines. Considerable phenotypic variation was observed for all traits. A total of 228 quantitative trait loci (QTLs) were significantly associated with 12 starch quality traits through genome-wide association studies (GWAS). By integrating a dynamic transcriptome analysis of two maize inbred lines with contrasting starch quality, we identified 60 candidate genes. One gene, waxy1, encoding a starch synthase, was found to be associated with enthalpy of gelatinization (&#x394;Hgel) and pasting temperature (Ptemp). Six variants in waxy1 contributed to natural variation in &#x394;Hgel and Ptemp, and a cost-effective InDel and two PARMS-based molecular markers were developed and validated in 144 maize inbred lines, enabling efficient marker-assisted selection. Our findings provide key genes and molecular markers for high-quality maize breeding with improved starch properties.

Zea mays↗

Endozoicomonas acroporae enhances coral thermal resilience through host-microbe coordination.

Probiotics hold promise for enhancing coral resilience under climate-driven thermal stress, yet their mechanisms remain poorly understood. Although the bacterial genus Endozoicomonas has been proposed to benefit corals, in vivo evidence of beneficial effects on the host remains limited. Here, we establish Endozoicomonas acroporae Acr-14T as a coral probiotic and characterize its effects on the reef-building coral Stylophora pistillata. We show that E. acroporae Acr-14T enhances host thermal tolerance, colonizes coral tissues, and forms coral-associated microbial aggregates. Microbial profiling indicates that probiotic treatment is associated with reduced relative abundances of opportunistic microbes and enrichment of putatively beneficial taxa. To support transcriptomic analyses, we assembled a chromosome-level genome of S. pistillata clade 1 (Pacific lineage) and found that E. acroporae Acr-14T treatment mitigates heat-induced protein-folding stress and apoptotic signaling. Single-cell transcriptomics further revealed altered expression of genes involved in S-adenosylmethionine (SAMe) metabolism and pro-survival signaling in gastrodermal cells of probiotic-treated corals. Together, our results provide a cell-type-resolved view of host responses linked to Endozoicomonas-mediated coral thermal resilience and offer insight into molecular mechanisms implicated in host-microbe interactions under environmental stress.

Animals↗

Complex analysis of genes involved in the inflammatory response: interleukin-1-induced differential transcriptome of cultured human hepatoma HepG2 cells.

The systemic inflammatory reaction (acute phase response) is induced by many noxious stimuli but in all cases the inflammatory cytokines, such as interleukin-1-beta (IL-1beta) and interleukin-6 (IL-6), are involved. Liver cell response to inflammation manifested by a characteristic change in the profile of synthesized plasma proteins (acute phase proteins) has been extensively studied. Here we describe a model system of cultured human hepatoma HepG2 cells stimulated with IL-1beta to evaluate the transcriptome induced by this cytokine during 24 h of treatment. By using differential display analysis we found IL-1beta-induced upregulation of several genes coding for cellular trafficking/motor proteins, proteins participating in the translation machinery or involved in posttranscription/posttranslation modifications, proteases, proteins involved in cellular metabolism, activity modulators, proteins of the cell cycle machinery and also some new proteins so far functionally not classified.

Carcinoma, Hepatocellular↗

Multi-omics reveal molecular changes during suspension adaptation of HEK293 cells.

Human embryonic kidney 293 (HEK293) cells have been successfully adapted from adherent to suspension culture and widely applied in both scientific research and the pharmaceutical industry. Although some studies investigated the variances between established adherent and suspension HEK293 cells of different strains, specific alterations in the cells during this consecutive process of suspension adaptation and possible factors driving this process have not been well described. Here, we adapted adherent HEK293 to suspension with desirable cell growth and high productivity for recombinant adenoviral vectors, and cells at several stages throughout the process were characterized. Slower cell growth, lower glucose uptake, increased lactate production, and weaker cell-surface adhesion were observed in suspension cells compared to their adherent counterparts. We further performed transcriptomics, proteomics, and metabolomics analysis to identify key cellular switches. A total of 2476 differentially expressed genes were found, including 1218 upregulated and 1258 downregulated genes in suspension cells. A similar and correlated pattern was observed in the proteomic study, and 702 differentially expressed metabolites were identified by untargeted metabolomics. In light of enrichment analysis, we summarized that HEK293 adherent cells survived and adapted to suspension culture via structural remodeling, metabolic shift and stress resistance. Our results provide a molecular enlightenment for suspension adaptation and potential directions for rational modification of HEK293 cell lines for future use. KEY POINTS: &#x2022; Suspension adaptation reduced adhesion and reshaped the HEK293 cytoskeleton. &#x2022; Multi-omics revealed metabolic rewiring and enhanced stress resistance. &#x2022; An optimized suspension line outperformed an internal HEK293 suspension reference.

Humans↗

Genomic and Transcriptomic Landscape of Epstein-Barr Virus-Positive Inflammatory Follicular Dendritic Cell Sarcoma: A Multicenter Study.

Epstein-Barr virus (EBV)-positive inflammatory follicular dendritic cell sarcoma (EBV+ IFDCS) is a rare indolent malignant neoplasm, which occurs almost exclusively in the liver or spleen and may arise from a common EBV-infected mesenchymal cell that differentiates along the follicular or fibroblastic dendritic cell pathway. Despite its rarity, it presents a pressing need for an improved understanding of its genetic underpinnings and potential treatment strategies for recurrent or disseminated cases. To address this, we conducted comprehensive whole-exome sequencing and transcriptome sequencing (mRNA-seq) analyses on 31 and 6 cases of EBV+ IFDCS, respectively, collected from multiple centers in China. We also compared the genetic features of EBV+ IFDCS with those of other EBV-associated malignancies. Our analyses revealed a relatively high somatic mutation rate and widespread copy number variations affecting the major histocompatibility complex-I/II in EBV+ IFDCS. Integrated mutational profiling identified key signaling pathways involved in epigenetic regulation, NF-&#x3ba;B signaling, RTK/RAS/PI(3)K, and the Hippo pathway. Furthermore, we identified several frequently altered genes that could serve as potential therapeutic targets in EBV+ IFDCS. Transcriptomic analysis unveiled significant upregulation of pathways related to virus infection, immune responses, and multiple immune checkpoint genes in EBV+ IFDCS. Comparative analysis demonstrated clear genetic distinctions between EBV+ IFDCS and other EBV-associated tumors. In conclusion, our study provides comprehensive insights into the unique genomic and transcriptomic landscape of EBV+ IFDCS. We have identified multiple genetic alterations that likely contribute to the development and progression of this malignancy. Our results suggest that targeted therapy and immune checkpoint inhibitors may hold promise as potential therapeutic approaches for patients with recurrent or disseminated EBV+ IFDCS.

Humans↗

Complex Genetics and Regulatory Drivers of Hypermobile Ehlers-Danlos Syndrome: Insights from Genome-Wide Association Study Meta-analysis.

BACKGROUND: Hypermobile Ehlers-Danlos syndrome (hEDS) is the most common subtype of EDS, a group of heritable connective tissue disorders. Clinically, hEDS is defined by generalized joint hypermobility and chronic musculoskeletal pain, but its impact extends beyond the musculoskeletal system. Affected individuals frequently experience autonomic, gastrointestinal, immune, and neuropsychiatric involvement, highlighting both the multisystemic nature of the condition and challenges of diagnosis. In contrast to other EDS subtypes with defined genetic causes, the molecular basis of hEDS has remained elusive. METHODS: We conducted a genome-wide association study (GWAS) of hEDS across three case controls studies, including 1,815 cases and 5,008 ancestry-matched controls. Fixed-effects meta-analysis of 6.2 million variants was complemented with LDAK gene-based association testing, transcriptome-wide association studies, and integrative annotation across multiple tissues and cell types including eQTLs, enhancer marks and open chromatin accessibility profiles, supported by luciferase assays on one candidate variant. LD-score genetic correlations were assessed between hEDS and 19 frequently reported comorbid conditions. RESULTS: Two loci reached genome-wide significance, including a regulatory region near the atypical chemokine receptor 3 gene (ACKR3) on chromosome 2. Functional annotation supports ACKR3 risk alleles colocalize with eQTLs in tibial nerve, alter enhancer activity, and generate a de novo AHR transcription factor regulatory site, implicating neuroimmune and pain signaling pathways. Gene-based and transcriptome-wide analyses identified common variants in a locus containing multiple candidates, including SLC39A13, a zinc transporter critical for connective tissue development previously implicated in a rare form of EDS, and PSMC3, a gene involved in central nervous system development. LD-score regression revealed significant genetic correlations between hEDS and joint hypermobility, myalgic encephalomyelitis/chronic fatigue syndrome, fibromyalgia, depression, anxiety, autism spectrum disorder, migraine, and gastrointestinal diseases. CONCLUSIONS: These results establish the first evidence of common variant contributions to hEDS, supporting a complex, multisystem model involving neuroimmune-stromal dysregulation. Our findings add novel indications to hEDS pathogenesis and provide solid foundations for future molecular definition and therapeutic discovery.

Genome-wide association study↗

Technical advances: genome-wide cDNA-AFLP analysis of the Arabidopsis transcriptome.

cDNA-AFLP, a technology historically used to identify small numbers of differentially expressed genes, was adapted as a genome-wide transcript profiling method. mRNA levels were assayed in a diverse range of tissues from Arabidopsis thaliana plants grown under a variety of environmental conditions. The resulting cDNA-AFLP fragments were sequenced. By linking cDNA-AFLP fragments to their corresponding mRNAs via these sequences, a database was generated that contained quantitative expression information for up to two-thirds of gene loci in A. thaliana, ecotype Ws. Using this resource, the expression levels of genes, including those with high nucleotide sequence similarity, could be determined in a high-throughput manner merely by comparing cDNA-AFLP profiles with the database. The lengths of cDNA-AFLP fragments inferred from their electrophoretic mobilities correlated well with actual fragment lengths determined by sequencing. In addition, the concentrations of AFLP fragments from single cDNAs were highly correlated, illustrating the validity of cDNA-AFLP as a quantitative, genome-wide, transcript profiling method. cDNA-AFLP profiles were also qualitatively consistent with mRNA profiles obtained from parallel microarray analysis, and with data from previous studies.

Arabidopsis↗

Sepsis gene expression profiling: murine splenic compared with hepatic responses determined by using complementary DNA microarrays.

OBJECTIVE: DNA microarrays allow genome-wide assessment of changes in relative messenger RNA abundance and thus can be used to monitor changes in gene expression. The aim of this series of experiments was to gain experience in sepsis gene expression profiling in a well-accepted model of murine polymicrobial abdominal sepsis and begin characterizing (in the parlance of genomics) the sepsis "transcriptome." DESIGN: Prospective animal study. SETTING: University-based animal research facility.SUBJECTS C57BL/6 mice. INTERVENTIONS: After induction of general anesthesia, cecal ligation and puncture were performed to induce peritonitis and polymicrobial sepsis. The control group had sham laparotomy only. Three samples of spleen and liver were collected from septic and sham animals at 24 hrs after laparotomy. Changes in expression were measured for 588 annotated mouse genes by using a commercially available complementary DNA microarray kit. MEASUREMENTS AND MAIN RESULTS: Broad-scale gene expression profiles were characterized for septic liver and spleen and compared with sham controls. The analytical tools used included commercially available software packages and a novel analysis program. Very little overlap was observed in the septic gene expression profiles of these two organs. Most of the genes identified have previously been linked to regulation of the inflammatory response; importantly, however, some have not. In addition, hierarchical cluster analysis showed that cecal ligation and puncture at 24 hrs induced coordinate expression of genes that alter cell signaling and survival pathways in spleen, consistent with previously published reports of sepsis-induced splenocyte apoptosis. The current limitations of microarray analysis as reflected in these studies are also discussed. CONCLUSIONS: Microarray technology provides a powerful new tool for rapidly analyzing tissue-specific changes in gene expression induced by sepsis in animal models. To our knowledge, these data constitute the first report on the use of microarrays to determine the sepsis transcriptome.

Animals↗

Genomic and transcriptomic features of HBV integration in treatment-na&#xef;ve, HBeAg-positive children with chronic HBV infection.

BACKGROUND: Hepatitis B virus (HBV) integration represents a major obstacle to curing HBV; however, the landscape of HBV integration and local immune response to transcriptionally active viral integration in children with chronic HBV infection remain unclear. Herein, we aimed to elucidate this landscape in this population. METHODS: Genomic analyses using a probe-based capture strategy were performed on 18 children and 28 adults with chronic HBV infection. Spatial transcriptomics (ST) was performed on 12 children from our cohort and 3 adults from a public database. FINDINGS: All patients were hepatitis B e antigen (HBeAg)-positive and treatment-na&#xef;ve. Genomically, children exhibited significantly lower clonal expansion level of HBV-integrated hepatocytes than adults, despite comparable unique breakpoint counts. After adjusting for confounding variables, age was identified as an independent risk factor for total frequency of unique integration breakpoints (b = 3.22, P = 0.005). Spatially, ST revealed that spots with transcriptionally active viral integration exhibited a sparse distribution and accounted for a low proportion of all spots in children. Notably, at these spots, children showed reduced adaptive immune cells (e.g., CD8+ T cells) but increased innate components (myeloid cells, Kupffer cells, activated dendritic cells) and APC co-stimulation, whereas adults exhibited a uniform reduction of immune cell populations. INTERPRETATION: Compared with adults, children exhibit lower clonal expansion of HBV-integrated hepatocytes and distinct immune profiles in response to transcriptionally active viral integration, offering new insights into their differing clinical course. FUNDING: Key Laboratory of Molecular Biology for Infectious Diseases (Ministry of Education).

Humans↗

Unlocking the Full Potential of Spatial Omics in Plants: Practical Challenges, Solutions, and a Path Forward.

Spatial omics technologies are providing new opportunities for plant biology by enabling molecular profiling within structurally intact tissues, revealing spatially organised cell states, developmental gradients, and regulatory interactions. While spatial transcriptomics has driven early advances, the field is rapidly expanding toward integrated spatial multi-omics by combining single-cell and spatial transcriptomic, epigenomic, proteomic, and metabolomic data. These approaches offer new opportunities to study development, physiology, and plant biotic and abiotic interactions in spatially preserved cellular contexts. However, despite rapid adoption, the field remains constrained by plant-specific challenges when applying technologies largely developed for animal systems. Compared with animal systems, plant tissues pose additional challenges due to rigid cell walls, and diverse chemistries, complicating sample preparation, cell and subcellular segmentation, signal detection, and data integration. As a result, many studies rely on bespoke protocols and analysis pipelines that are often difficult to reproduce or generalise. Here, we provide a practical, solution-oriented synthesis of current bottlenecks across experimental and computational pipelines, highlight emerging strategies to overcome these limitations, and propose a roadmap for community-driven protocol sharing, benchmarking, and integration across spatial and multi-omics modalities. Addressing these challenges will be essential to establish spatial omics as a routine and scalable tool for plant biology.

Journal Article↗

Comparative Transcriptomic Analyses Identify Candidate Genes for Convergent Reproductive Shifts in a Bimodal Viviparous Amphibian.

Shifts in reproductive mode represent key evolutionary innovations that shape species' life histories and evolutionary trajectories. Species showing bimodal reproductive strategies with multiple independent origins offer a rare opportunity to gain insights into the adaptive processes and mechanisms underlying convergent traits. The fire salamander, Salamandra salamandra, is the only amphibian exhibiting intraspecific variation in reproductive mode across multiple independent reproductive shifts, enabling investigation of the transition between larviparity (females give birth to aquatic larvae) and pueriparity (females give birth to fully developed terrestrial juveniles) within a single species and across different timescales. Pueriparity is an adaptive innovation that skips the aquatic larval stage, allowing individuals to exploit habitats with no available water bodies. The fire salamander is larviparous across most of its range, but pueriparity has evolved independently at least three times: once in the early Pleistocene within S. s. bernardezi in the mountains of northern Spain, and more recently on two land-bridge islands (NW Spain) inhabited by S. s. gallaica. To identify candidate genes associated with these distinct reproductive modes, we compared gene expression profiles of the uterus and oviduct of pregnant females across two independent evolutionary transitions using RNA-sequencing. We detected shared changes in maternal gene expression among pueriparous S. s. bernardezi and S. s. gallaica relative to their larviparous counterparts, in addition to differences unique to each independent evolutionary transition. Functional enrichment analyses indicated that differentially expressed genes were associated with reproductive timing, angiogenesis, and maternal signalling, consistent with the phenotypic differences observed in the uterine environment and embryonic development between the two reproductive modes. This study represents an important first step towards understanding the genomic basis of the evolution of pueriparity in a remarkable bimodal reproductive system, and provides transcriptomic resources and candidate genes for future research into the genomic architecture underlying this poorly understood adaptive trait.

Animals↗

Comparative transcriptomics uncovers poplar and fungal genetic determinants of ectomycorrhizal compatibility.

Ectomycorrhizal symbiosis supports tree growth and is crucial for nutrient cycling and temperate and boreal ecosystems functioning. The establishment of functional ectomycorrhiza (ECM) first requires the association of compatible partners. However, host and fungal genetic determinants governing mycorrhizal compatibility are unknown. To identify such factors in poplar and its fungal associates, we mined existing and de novo tree and fungal transcriptional datasets. We identified co-expressed genes enabling ECM symbiosis at early and mature stages of the interaction. These sets of genes can be divided into general fungal-sensing and ECM-specific components. We highlight the importance of fungal modulation of plant JA-related defenses and the regulation of secretory pathways for ECM compatibility, including upregulation of key fungal small secreted proteins, the downregulation of plant secreted peroxidases, and the downregulation of plant cell wall remodeling proteins concomitantly with the upregulation of fungal glycosyl hydrolases acting on pectin. Not only gene regulation, but also its temporal scale and dynamics seem to play a crucial role for mycorrhizal compatibility. The expression profile of the host Common Symbiosis Pathway and nutrient transporters was also studied, revealing constitutive levels of expression and moderate upregulation in compatible ECM interactions. Overall, these results underscore the importance of novel biological functions during the establishment of ECM symbiosis, help us gain insights into the molecular events determining mycorrhiza compatibility, and serve as a data-rich transcriptomic resource to open new research questions in the field.

Mycorrhizae↗

Gene expression profiles of human breast cancer progression.

Although distinct pathological stages of breast cancer have been described, the molecular differences among these stages are largely unknown. Here, through the combined use of laser capture microdissection and DNA microarrays, we have generated in situ gene expression profiles of the premalignant, preinvasive, and invasive stages of human breast cancer. Our data reveal extensive similarities at the transcriptome level among the distinct stages of progression and suggest that gene expression alterations conferring the potential for invasive growth are already present in the preinvasive stages. In contrast to tumor stage, different tumor grades are associated with distinct gene expression signatures. Furthermore, a subset of genes associated with high tumor grade is quantitatively correlated with the transition from preinvasive to invasive growth.

Breast Neoplasms↗