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Objective: Gastric cancer (GC) is the world's third-leading cause of cancer-related mortality; the prognosis for GC patients remains poor in terms of a lack of reliable biomarkers for early diagnosis and immune therapy response prediction. Here, we aim to discover the connection between chemokine ligand 14 (CCL14) expression in the gastric tumor microenvironment (TME) and its clinical significance and investigate its correlation with immune cell infiltration. Methods: We assessed CCL14 mRNA expression and its interrelation with tumor-infiltrating immune cells (TILs) using bioinformatics analysis in gastric cancer. CCL14 protein expression, TILs, and immune checkpoints were detected by multiple immunohistochemistry analyses in gastric cancer tissue microarrays. Then, we conducted statistics analysis to determine the association between CCL14-related patient survival and immune cell infiltration (p < 0.05). Results: We found that the CCL14 protein was separately expressed in the carcinoma cells and TILs in stomach cancer tissues. The CCL14 protein was related to tumor differentiation and tumor depth and positively correlated with the presentation of LAG3 and PD-L1 in gastric cancer cells. In addition, the CCL14 protein in the TILs of gastric cancer tissues was related to Lauren's type cells, T cells (CD4+ and CD8+), and CD68+ macrophages in the TME. Kaplan-Meier survival and multivariate analyses showed that the CCL14 expression in gastric cancer cells was an independent prognostic factor. Conclusion: Our study illustrated that CCL14 is a poor prognosis biomarker in gastric cancer, which may be associated with the potential for immunotherapy.
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Circular RNAs (circRNAs) represent a novel class of non-coding RNAs that play significant roles in tumorigenesis and tumor progression. High-throughput sequencing of gastric cancer (GC) tissues has identified circRNA BIRC6 (circBIRC6) as a potential circRNA derived from the BIRC6 gene, exhibiting significant upregulation in GC tissues. The expression of circBIRC6 is notably elevated in GC patients. Functionally, it acts as a molecular sponge for miR-488, consequently upregulating GRIN2D expression and promoting GC proliferation, migration, and invasion. Moreover, overexpression of circBIRC6 leads to increased GRIN2D expression, which in turn enhances caveolin-1 (CAV1) expression, resulting in autophagy deficiency due to miR-488 sequestration. This cascade of events significantly influences tumorigenesis in vivo. Our findings collectively illustrate that the CircBIRC6-miR-488-GRIN2D axis fosters CAV1 expression in GC cells, thereby reducing autophagy levels. Both circBIRC6 and GRIN2D emerge as potential targets for treatment and independent prognostic factors for GC patients.
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MicroRNAs , Neoplasias Gástricas , Humanos , Autofagia , Caveolina 1/genética , Caveolina 1/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Transformação Celular Neoplásica , Regulação Neoplásica da Expressão Gênica , MicroRNAs/genética , MicroRNAs/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , RNA Circular/genética , RNA Circular/metabolismo , Neoplasias Gástricas/patologiaRESUMO
BACKGROUND: Patients with glioma have limited treatment options and experience poor prognoses. Therefore, it is urgently needed to explore new diagnostic and therapeutic targets. OBJECTIVE: This study aimed to investigate the relevance of WSC domain-containing 2 (WSCD2) expression to glioma, clinicopathological characteristics, tumor-infiltrating immune cells (TILs), and patient prognosis. METHODS: We analyzed WSCD2 mRNA expression in glioma tissues and patient survival using the Gene Expression Profiling Interactive Analysis database. Furthermore, the relationship between the expressions of WSCD2 mRNA and TILs in gliomas was evaluated utilizing the Tumor Immune Estimation Resource database. Lastly, we employed multiplex immunohistochemistry to detect the protein expressions of WSCD2 and TILs in glioma tissues. RESULTS: WSCD2 mRNA expression in glioma tissues was lower than that in tissues of benign brain disease. High WSCD2 mRNA expression was also significantly associated with a favorable outcome. Additionally, WSCD2 mRNA expression was correlated with TIL expression in glioma; however, no such relationship was detected between the protein expressions of WSCD2 and TILs in glioma tissues. Cox regression multivariate analysis and Kaplan-Meier survival analysis showed that WSCD2 expression in glioma tissues could be an independent prognostic factor. CONCLUSION: This study highlights the correlation between WSCD2 expression and TILs and demonstrates the prognostic significance of WSCD2 in glioma. Furthermore, our results suggest that WSCD2 may be a potential immunotherapy target in glioma.
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Serpin family A member 1 (SERPINA1) encodes a protease inhibitor participating in many human diseases, but its value in immunoregulation and prognosis of human cancers remains unclear. In this study, through comprehensive analysis of data from The Cancer Genome Atlas (TCGA) datasets, we found that SERPINA1 was dysregulated in many cancers compared with normal tissues. SERPINA1 expression was significantly associated with prognosis, immune subtype, molecular subtype, immune checkpoint (ICP) genes, tumor mutational burden (TMB), microsatellite instability (MSI), and the estimation of stromal and immune cells in malignant tumor tissues using expression data (ESTIMATE) score. There was a strong connection between SERPINA1 expression and tumor-infiltrating lymphocytes, and SERPINA1 showed significant relation to gene markers of immune cells in digestive tumors. Fluorescence-based multiplex immunohistochemistry confirmed that SERPINA1 protein expression was related to clinicopathologic features and immune infiltrates in hepatic cancer. This study suggests that SERPINA can potentially serve as a novel biomarker for cancer prognosis and immunotherapy.
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Neoplasias Hepáticas , Humanos , Antivirais , Terapia Enzimática , Neoplasias Hepáticas/genética , Prognóstico , Inibidores de ProteasesRESUMO
Alterations in protein glycosylation affect tumor progression and immune responses in the tumor microenvironment. Keratinocyte-associated protein 2 (KRTCAP2) encodes the corresponding proteins involved in N-glycosylation. The clinical predictive significance and immune role of KRTCAP2 in hepatocellular carcinoma (HCC) largely remain elusive. Combining bioinformatics tools and multiplex immunohistochemistry analysis, we evaluated the KRTCAP2 expression in the HCC tumor microenvironment. The results showed that KRTCAP2 mRNA and protein expression were markedly increased in HCC tissues. Furthermore, high KRTCAP2 expression was an independent predictive factor of unfavorable prognosis in HCC. Moreover, high KRTCAP2 protein expression was associated with a lower proportion of CD8+ T cells and CD68+ macrophages in the stroma region. There was also a lower proportion of CD8+ T cells in the tumor region with high KRTCAP2 protein expression. Specifically, KRTCAP2 expression showed an inverse relationship with programmed cell death ligand-1 in HCC. Analysis of immunophenoscore showed that the low KRTCAP2 expression group had a stronger ability to predict response to immune checkpoint inhibitors. In conclusion, KRTCAP2 had a significant prognostic value for HCC and was correlated with the immune microenvironment. Our findings suggest that KRTCAP2 is a prognostic marker for HCC patients with potential clinical implications for predicting immunotherapeutic responsiveness.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Humanos , Biomarcadores/metabolismo , Carcinoma Hepatocelular/diagnóstico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/tratamento farmacológico , Linfócitos T CD8-Positivos/metabolismo , Neoplasias Hepáticas/tratamento farmacológico , Prognóstico , Microambiente TumoralRESUMO
Background: TP53I13 is a protein coding tumor suppression gene encoded by the tumor protein p53. Overexpression of TP53I13 impedes tumor cell proliferation. Nevertheless, TP53I13 role and expression in the emergence and progression of glioma (low-grade glioma and glioblastoma) are yet to be identified. Thus, we aim to use comprehensive bioinformatics analyses to investigate TP53I13 and its prognostic value in gliomas. Methods: Multiple databases were consulted to evaluate and assess the expression of TP53I13, such as the Cancer Genome Atlas (TCGA), the Chinese Glioma Genome Atlas (CGGA), GeneMANIA, and Gene Expression Profiling Interactive. TP53I13 expression was further explored using immunohistochemistry (IHC) and multiplex immunohistochemistry (mIHC). Through Gene Set Enrichment Analysis (GSEA), the biological functions of TP53I13 and metastatic processes associated with it were studied. Results: The expression of TP53I13 was higher in tumor samples compared to normal samples. In samples retrieved from the TCGA and CGGA databases, high TP53I13 expression was associated with poor survival outcomes. The analysis of multivariate Cox showed that TP53I13 might be an independent prognostic marker of glioma. It was also found that increased expression of TP53I13 was significantly correlated with PRS type, status, 1p/19q codeletion status, IDH mutation status, chemotherapy, age, and tumor grade. According to CIBERSORT (Cell-type Identification by Estimating Relative Subsets of RNA Transcript), the expression of TP53I13 correlates with macrophages, neutrophils, and dendritic cells. GSEA shows a close correlation between TP53I13 and p53 signaling pathways, DNA replication, and the pentose phosphate pathway. Conclusion: Our results reveal a close correlation between TP53I13 and gliomas. Further, TP53I13 expression could affect the survival outcomes in glioma patients. In addition, TP53I13 was an independent marker that was crucial in regulating the infiltration of immune cells into tumors. As a result of these findings, TP53I13 might represent a new biomarker of immune infiltration and prognosis in patients with gliomas.
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Neoplasias Encefálicas , Glioma , Humanos , Proteína Supressora de Tumor p53/genética , Prognóstico , Neoplasias Encefálicas/patologia , Neutrófilos/metabolismo , Glioma/patologia , Biomarcadores , Macrófagos/metabolismo , Fibroblastos/metabolismo , RNARESUMO
Background: The tumor immune microenvironment (TME) is associated with cancer progression and immune escape. Although KLHDC8A has been reported in glioma in vitro, the expression and clinical significance of this gene in clinical samples are unknown. Methods: The Cancer Genome Atlas and Chinese Glioma Genome Atlas databases were used to evaluate the mRNA expression level of KLHDC8A and its significance in the glioma TME. Tissue microarray-based multiple immunohistochemical staining was conducted to determine KLHDC8A protein levels and characterize the immune signature of tumor-infiltrating immune cells in gliomas. Results: Tumor cells and tumor-associated macrophages expressed KLHDC8A. The expression of KLHDC8A was higher in glioma tissues than in normal brain tissues and was associated with patient clinical characteristics. Gliomas exhibited a high abundance of macrophages, neutrophils, regulatory T cells, and the immune checkpoint PD-L1, as well as high KLHDC8A expression. Cox regression analysis showed that KLHDC8A+CD68+ macrophages and KLHDC8A predicted unfavorable survival in patients with glioma. Finally, protein-protein interaction network analysis showed that the KLHDC8A expression was associated with hypoxia and oxidative stress. Conclusions: KLHDC8A is a potential marker for the clinical diagnosis of glioma. The immune characteristics of macrophages play a crucial role in predicting patients with glioma, providing a new avenue for targeted glioma therapy.
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Neoplasias Encefálicas , Proteínas de Ciclo Celular/metabolismo , Glioma , Antígeno B7-H1/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Glioma/metabolismo , Humanos , Macrófagos/metabolismo , Estresse Oxidativo , Prognóstico , RNA Mensageiro/metabolismo , Microambiente TumoralRESUMO
Gastric cancer ranked third worldwide in terms of mortality. The immediate priority is to search for new prognosticative or therapeutic targets. This research aims to examine the function of the NADH:ubiquinone oxidoreductase subunit S4 (NDUFS4) in the malignant phenotype of gastric carcinoma. We analyzed the correlation between NDUFS4 expression and gastric cancer via bioinformatics analysis and cancer tissue microarray via immunohistochemistry. Also, we detected the phenotype change in gastric cancer cells after NDUFS4 was downregulated. NDUFS4's high expression in gastric cancer tissues showed an association with terminal TNM stage and unfavorable survival. Furthermore, downregulation of NDUFS4 decreased gastric cancer cell proliferation, migration and invasion. Nude mouse models revealed that NDUFS4 promotes tumor growth. This investigation highlights the prognostic role of NDUFS4 in gastric cancer. Our results also creatively ascertained NDUFS4 as a candidate for gastric cancer therapeutic targets.
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Neoplasias Gástricas , Camundongos , Animais , Neoplasias Gástricas/patologia , Movimento Celular/genética , Proliferação de Células/genética , Prognóstico , Imuno-Histoquímica , Camundongos Nus , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Complexo I de Transporte de Elétrons/genética , Complexo I de Transporte de Elétrons/metabolismoRESUMO
Background: The tumor microenvironment is mainly composed of tumor-infiltrating immune cells (TIICs), fibroblast, extracellular matrix, and secreted factors. TIICs are often associated with sensitivity to immunotherapy and the prognosis of multiple cancers, yet the predictive role of individual cells on tumor prognosis is limited. Methods: Based on single-sample gene set enrichment analysis, we combined three Gene Expression Omnibus (GEO) cohorts to build a TIIC model for risk stratification and prognosis prediction. The performance of the TIIC model was validated using our clinical cohort and the TCGA cohort. To assess the predictive power of the TIIC model for immunotherapy, we plotted the receiver operating characteristic curve with the IMvigor210 and GSE135222 cohorts. Results: Chemokines, tumor-infiltrating immune cells, and immunomodulators differed between the two TIIC groups. The TIIC model was vital for predicting the outcome of immunotherapy. In our clinical samples, we verified that the expression levels of PD-1 and PD-L1 were higher in the low TIIC score group than in the high TIIC score group, both in the tumor and stroma. Conclusions: Collectively, the TIIC model could provide a novel idea for immune cell targeting strategies in gastric cancer and predict the survival outcome of patients.
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Neoplasias Gástricas , Humanos , Fatores Imunológicos , Imunoterapia , Fenótipo , Microambiente TumoralRESUMO
As bone marrow transplant (BMT) is gradually applied to the study of central nervous system (CNS) disease, it is needed to investigate the proper dose of chemotherapy to eradicate bone marrow cells while bringing little damage to brain. In the present study, we established a BMT model with varied busulfan and cyclophosphamide (Bu-Cy) dosages. The recipient mice's chimera rate, neuronal death, neuroinflammation, and behavioral functions were all investigated. Chimerism of peripheral blood cells was shown to rise with Bu-Cy treatment doses, with 60.7% in the Bu(20 mg/kg)/Cy(100 mg/kg) group and 93.0% in the Bu(35 mg/kg)/Cy(100 mg/kg) group. Recipients with Bu(35 mg/kg)/Cy(100 mg/kg) therapy had brain injury, increased neuroinflammation, diminished neurogenesis and cognitive abnormalities, whereas animals given a lesser dosage had no such brain damages. Conclusively, considering the chimerism and the possibility to damage brain, we recommend Bu(20 mg/kg)/Cy(100 mg/kg) is the ideal dose in BMT for studying CNS diseases in the C57/BL6 mouse strain.
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Transplante de Medula Óssea , Doenças Neuroinflamatórias , Animais , Bussulfano/uso terapêutico , Bussulfano/toxicidade , Ciclofosfamida/toxicidade , Camundongos , NeurogêneseRESUMO
Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase expressed at early stages of normal development and in various cancers including ALK-positive anaplastic large cell lymphoma (ALK+ ALCL), in which it is the main therapeutic target. ALK tyrosine kinase inhibitors (ALK TKIs) have greatly improved the prognosis of ALK+ALCL patients, but the emergence of drug resistance is inevitable and limits the applicability of these drugs. Although various mechanisms of resistance have been elucidated, the problem persists and there have been relatively few relevant clinical studies. This review describes research progress on ALK+ ALCL including the application and development of new therapies, especially in relation to drug resistance. We also propose potential treatment strategies based on current knowledge to inform the design of future clinical trials.
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Deficits in the clearance of amyloid ß protein (Aß) by the peripheral system play a critical role in the pathogenesis of sporadic Alzheimer's disease (AD). Impaired uptake of Aß by dysfunctional monocytes is deemed to be one of the major mechanisms underlying deficient peripheral Aß clearance in AD. In the current study, flow cytometry and biochemical and behavioral techniques were applied to investigate the effects of polysaccharide krestin (PSK) on AD-related pathology in vitro and in vivo. We found that PSK, widely used in therapy for various cancers, has the potential to enhance Aß uptake and intracellular processing by human monocytes in vitro. After administration of PSK by intraperitoneal injection, APP/PS1 mice performed better in behavioral tests, along with reduced Aß deposition, neuroinflammation, neuronal loss, and tau hyperphosphorylation. These results suggest that PSK holds promise as a preventive agent for AD by strengthening the Aß clearance by blood monocytes and alleviating AD-like pathology.
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Doença de Alzheimer , Peptídeos beta-Amiloides , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Cognição , Modelos Animais de Doenças , Camundongos , Camundongos Transgênicos , Monócitos/metabolismo , Monócitos/patologia , Polissacarídeos/farmacologia , Polissacarídeos/uso terapêutico , ProteoglicanasRESUMO
Hepatocellular carcinoma (HCC) is the second most lethal malignant tumor because of its significant heterogeneity and complicated molecular pathogenesis. Novel prognostic biomarkers are urgently needed because no effective and reliable prognostic biomarkers currently exist for HCC patients. Increasing evidence has revealed that pyroptosis plays a role in the occurrence and progression of malignant tumors. However, the relationship between pyroptosis-related genes (PRGs) and HCC patient prognosis remains unclear. In this study, 57 PRGs were obtained from previous studies and GeneCards. The gene expression profiles and clinical data of HCC patients were acquired from public data portals. Least absolute shrinkage and selection operator (LASSO) Cox regression analysis was performed to establish a risk model using TCGA data. Additionally, the risk model was further validated in an independent ICGC dataset. Our results showed that 39 PRGs were significantly differentially expressed between tumor and normal liver tissues in the TCGA cohort. Functional analysis confirmed that these PRGs were enriched in pyroptosis-related pathways. According to univariate Cox regression analysis, 14 differentially expressed PRGs were correlated with the prognosis of HCC patients in the TCGA cohort. A risk model integrating two PRGs was constructed to classify the patients into different risk groups. Poor overall survival was observed in the high-risk group of both TCGA (p < 0.001) and ICGC (p < 0.001) patients. Receiver operating characteristic curves demonstrated the accuracy of the model. Furthermore, the risk score was confirmed as an independent prognostic indicator via multivariate Cox regression analysis (TCGA cohort: HR = 3.346, p < 0.001; ICGC cohort: HR = 3.699, p < 0.001). Moreover, the single-sample gene set enrichment analysis revealed different immune statuses between high- and low-risk groups. In conclusion, our new pyroptosis-related risk model has potential application in predicting the prognosis of HCC patients.
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To study the molecular mechanism that underpins crosstalk between plant growth and disease resistance, we performed a mutant screening on tobacco and created a recessive mutation that caused the phenotype of growth enhancement and resistance impairment (geri1). In the geri1 mutant, growth enhancement accompanies promoted expression of growth-promoting genes, whereas repressed expression of defense response genes is consistent with impaired resistance to diseases caused by viral, bacterial, and oomycete pathogens. The geri1 allele identifies a single genetic locus hypothetically containing the tagged GERI1 gene. The isolated GERI1 gene was predicted to encode auxin-repressed protein ARP1, which was determined to be 13.5 kDa in size. The ARP1/GERI1 gene was further characterized as a repressor of plant growth and an activator of disease resistance based on genetic complementation, gene silencing, and overexpression analyses. ARP1/GERI1 resembles pathogen-associated molecular patterns and is required for them to repress plant growth and activate plant immunity responses. ARP1/GERI1 represses growth by inhibiting the expression of AUXIN RESPONSE FACTOR gene ARF8, and ARP1/GERI1 recruits the NPR1 gene, which is essential for the salicylic-acid-mediated defense, to coregulate disease resistance. In conclusion, ARP1/GERI1 is an integral regulator for crosstalk between growth and disease resistance in the plant.
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Nicotiana/crescimento & desenvolvimento , Nicotiana/metabolismo , Doenças das Plantas/imunologia , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Quitina , DNA de Plantas/genética , DNA de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas/imunologia , Regulação da Expressão Gênica de Plantas/fisiologia , Predisposição Genética para Doença , Dados de Sequência Molecular , Mutação , Filogenia , Doenças das Plantas/genética , Proteínas de Plantas/genética , Nicotiana/genéticaRESUMO
The harpin protein Hpa1 produced by the bacterial blight pathogen of rice induces several growth-promoting responses in plants, activating the ethylene signaling pathway, increasing photosynthesis rates and EXPANSIN (EXP) gene expression levels, and thereby enhancing the vegetative growth. This study was attempted to analyze any mechanistic connections among the above and the role of gibberellin in these responses. Hpa1-induced growth enhancement was evaluated in Arabidopsis, tomato, and rice. And growth-promoting responses were determined mainly as an increase of chlorophyll a/b ratio, which indicates a potential elevation of photosynthesis rates, and enhancements of photosynthesis and EXP expression in the three plant species. In Arabidopsis, Hpa1-induced growth-promoting responses were partially compromised by a defect in ethylene perception or gibberellin biosynthesis. In tomato and rice, compromises of Hpa1-induced growth-promoting responses were caused by a pharmacological treatment with an ethylene perception inhibitor or a gibberellin biosynthesis inhibitor. In the three plant species, moreover, Hpa1-induced growth-promoting responses were significantly impaired, but not totally eliminated, by abolishing ethylene perception or gibberellin synthesis. However, simultaneous nullifications in both ethylene perception and gibberellin biosynthesis almost canceled the full effects of Hpa1 on plant growth, photosynthesis, and EXP2 expression. Theses results suggest that ethylene and gibberellin coregulate Hpa1-induced plant growth enhancement and associated physiological and molecular responses.
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Arabidopsis/fisiologia , Proteínas da Membrana Bacteriana Externa/farmacologia , Oryza/fisiologia , Reguladores de Crescimento de Plantas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Solanum lycopersicum/fisiologia , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Clorofila/metabolismo , Etilenos/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Giberelinas/metabolismo , Solanum lycopersicum/efeitos dos fármacos , Solanum lycopersicum/genética , Solanum lycopersicum/crescimento & desenvolvimento , Mutação , Oryza/efeitos dos fármacos , Oryza/genética , Oryza/crescimento & desenvolvimento , Fotossíntese , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/crescimento & desenvolvimento , Plântula/fisiologiaRESUMO
BACKGROUND: The phytohormone auxin mediates a stunning array of plant development through the functions of AUXIN RESPONSE FACTORs (ARFs), which belong to transcription factors and are present as a protein family comprising 10-43 members so far identified in different plant species. Plant development is also subject to regulation by TRANSPARENT TESTA GLABRA (TTG) proteins, such as NtTTG2 that we recently characterized in tobacco Nicotiana tabacum. To find the functional linkage between TTG and auxin in the regulation of plant development, we performed de novo assembly of the tobacco transcriptome to identify candidates of NtTTG2-regulated ARF genes. RESULTS: The role of NtTTG2 in tobacco growth and development was studied by analyzing the biological effects of gene silencing and overexpression. The NtTTG2 gene silencing causes repressive effects on vegetative growth, floral anthocyanin synthesis, flower colorization, and seed production. By contrast, the plant growth and development processes are promoted by NtTTG2 overexpression. The growth/developmental function of NtTTG2 associates with differential expression of putative ARF genes identified by de novo assembly of the tobacco transcriptome. The transcriptome contains a total of 54,906 unigenes, including 30,124 unigenes (54.86%) with annotated functions and at least 8,024 unigenes (14.61%) assigned to plant growth and development. The transcriptome also contains 455 unigenes (0.83%) related to auxin responses, including 40 putative ARF genes. Based on quantitative analyses, the expression of the putative genes is either promoted or inhibited by NtTTG2. CONCLUSIONS: The biological effects of the NtTTG2 gene silencing and overexpression suggest that NtTTG2 is an essential regulator of growth and development in tobacco. The effects of the altered NtTTG2 expression on expression levels of putative ARF genes identified in the transcriptome suggest that NtTTG2 functions in relation to ARF transcription factors.