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1.
Artigo em Inglês | MEDLINE | ID: mdl-38570918

RESUMO

CONTEXT: Medullary thyroid cancer (MTC) often exhibits aggressive growth with distant organ metastasis, leading to poor survival. OBJECTIVE: The question of whether primary tumor resection (PTR) is beneficial for patients with metastatic MTC remains a subject of debate. In this study, we evaluated the prognostic significance of organ-specific metastases and the number of metastatic organs in these patients, and we also conducted an analysis to determine the therapeutic value of PTR in managing this rare malignancy. MATERIALS AND METHODS: Patients initially diagnosed with metastatic MTC were identified within the Surveillance, Epidemiology, and End Results (SEER) database. Univariable and multivariable Cox proportional hazards regression models were performed to identify survival predictors. Survival outcomes were calculated using the Kaplan-Meier method and compared using the log-rank tests. RESULTS: A total of 186 patients with metastatic MTC at initial diagnosis from 2010 to 2020 were included. Bone, lung and liver were the most common metastatic organs. Patients with brain metastasis had significantly worse overall survival (OS) (p = 0.007) and cancer-specific survival (CSS) (p = 0.0013). Among all patients, 105 (56.45%) underwent PTR, and this group showed reduced overall mortality (OM) and cancer-specific mortality (CSM) (all p < 0.05). When analyzing different metastatic patterns, PTR significantly lowered the risk of OM and CSM for patients with bone, lung, liver, or distant lymph node (DLN) involvement (all p < 0.05). Additionally, among patients with one or two metastases, those undergoing surgical resection were significantly associated with favorable OS (p = 0.008) and CSS (p = 0.0247). CONCLUSIONS: PTR may confer therapeutic benefits for carefully selected individuals with metastatic MTCs. To integrate these insights into clinical decision-making settings, it is imperative to undertake multicenter prospective studies in the future.

2.
World J Clin Cases ; 10(32): 11889-11897, 2022 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-36405269

RESUMO

BACKGROUND: Intrahepatic cholangiocarcinoma (iCCA) is the second most common primary hepatic malignancy worldwide. However, currently available systemic therapies are of limited effectiveness, and the median overall survival of patients treated with first-line standard chemotherapy is less than one year. Immune checkpoint inhibitors have been used to treat solid tumors. Clinical studies recently explored the combination of chemotherapy and immunotherapy for CCA. However, the clinical significance of predictive biomarkers for chemo-immunotherapy in CCA remains unclear. It is also worth exploring whether a combination of chemotherapeutic agents can increase the sensitivity of CCA immunotherapy. CASE SUMMARY: This study reports a case of advanced iCCA in which clinical complete remission had been achieved using a programmed death 1 (PD-1) inhibitor and paclitaxel without known predictive biomarkers, but with BRCA1, KRAS, and NTRK3 mutations after rapid progression to first-line chemotherapy, and has remained in clinical complete remission for more than two years. This case suggests that chemo-immunotherapy is a potential therapeutic option for patients with iCCA and few known predictive biomarkers for immunotherapies as well as synergistic effect of the combination of paclitaxel and PD-1 monoclonal antibody. CONCLUSION: The combination of paclitaxel and PD-1 monoclonal antibodyr can be explored in patients with advanced iCCA.

3.
Front Endocrinol (Lausanne) ; 13: 859013, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35574031

RESUMO

Background: Patients with advanced thyroid carcinoma (TC), such as anaplastic thyroid carcinoma (ATC), poorly differentiated thyroid carcinoma (PDTC), and locally advanced papillary thyroid carcinoma (PTC), have poor prognoses and require novel treatments. Immune checkpoint (ICP) inhibitors have demonstrated encouraging and good results; nevertheless, their effect in advanced TCs remains largely unclear. Thus, we demonstrated ICP profiles and investigated their potential clinical significance. Methods: A total of 234 TC patients were involved, with 22 ATCs, 44 PDTCs, and 168 PTCs, including 58 advanced PTCs. Immunohistochemistry was performed to evaluate nine ICPs [programmed cell death ligand 1 (PDL1), Programmed cell death 1 (PD1), cytotoxic T lymphocyte-associated protein 4 (CTLA4), B and T lymphocyte attenuator (BTLA), T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), lymphocyte activation gene 3 (LAG3), V-domain immunoglobulin suppressor of T-cell activation (VISTA), B7 homolog 3 (B7-H3), and T-cell immunoglobulin and mucin domain- 3 protein (TIM3)] expression via tissue microarrays (TMAs), and clinical correlations were analyzed simultaneously. Results: ATC had the highest positive rate of ICPs among the three pathological types, as well as relatively high ICP co-expression. ATC with high expression of PDL1 positivity had a poor prognosis. Shorter survival was associated with VISTA, B7H3, TIM3, and TIGIT expression in PDTC. The greater the co-expression of these four ICPs, the poorer the prognosis in PDTC patients. VISTA and B7H3 were the two most commonly expressed ICPs in advanced PTC, both of which were linked to a poor prognosis. Conclusions: PDL1 is linked to the overall survival (OS) of ATC. A subset of PDTC is likely immunogenic with poor prognosis and co-expression of VISTA, B7H3, TIM3, and TIGIT. Furthermore, VISTA and B7H3 are prognostic biomarkers in advanced PTC. Single or combined blockade targeting these ICPs might be effective for advanced TCs in the future.


Assuntos
Adenocarcinoma , Carcinoma Anaplásico da Tireoide , Neoplasias da Glândula Tireoide , Receptor Celular 2 do Vírus da Hepatite A , Humanos , Proteínas de Checkpoint Imunológico/genética , Imunoglobulinas , Prognóstico , Receptores Imunológicos/metabolismo , Câncer Papilífero da Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/genética
4.
Endocrine ; 76(3): 660-670, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35366156

RESUMO

BACKGROUND: Mutations in DNA mismatch repair (MMR) genes associated with thyroid carcinoma (TC) have rarely been reported, especially in East Asian populations. METHODS: We examined tumor tissue from a cohort of 241 patients diagnosed with TC between 2008 and 2020. MMR proteins were detected using tissue microarray-based immunohistochemistry in order to identify MMR-protein-deficient (MMR-D) and MMR-protein-intact (MMR-I) tumors. We retrospectively summarized the clinicopathologic characteristics of patients with MMR-D TC, measured the expression of PD-L1, and recorded overall survival (OS) and other clinical outcomes. RESULTS: In our cohort, there were 18 (7.5%) MMR-D (MLH1, MSH2, MSH6, and PMS2) patients, including 12 with papillary TC (PTC) (6.7%), 2 with poorly differentiated TC (PDTC) (4.7%), and 4 with anaplastic TC (ATC) (22.2%). Half of them (9/18) showed a specific deletion in MSH6, and 6 of them also carried variants in the MSH6 and PMS2 gene. Survival was significantly better in patients with MMR-D ATC than in those with MMR-I tumors (p = 0.033). Four of the 18 MMR-D patients (22%) were found to be PD-L1 positive. Their OS was much shorter than that of PD-L1-negative patients. CONCLUSIONS: MMR-D and PD-L1 positivity appear to be associated with clinicopathological characteristics and prognosis in TC. The results indicate that MMR status may have important prognostic significance in TC. Therefore, immune checkpoint inhibitors that target the PD-1/PD-L1 pathway may be a treatment option for TCs.


Assuntos
Antígeno B7-H1 , Neoplasias da Glândula Tireoide , Antígeno B7-H1/genética , Biomarcadores Tumorais/genética , Biomarcadores Tumorais/metabolismo , Humanos , Endonuclease PMS2 de Reparo de Erro de Pareamento/genética , Estudos Retrospectivos , Neoplasias da Glândula Tireoide/genética
5.
J Ethnopharmacol ; 272: 113943, 2021 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-33617967

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Xuesaitong (XST) is a traditional Chinese medicine injection with neuroprotective properties and has been extensively used to treat stroke for many years. The main component of XST is Panax notoginseng saponins (PNS), which is the main extract of the Chinese herbal medicine Panax notoginseng. AIM OF THE STUDY: In this study, we investigated whether XST provided long-term neuroprotection by inhibiting neurite outgrowth inhibitor-A (Nogo-A) and the ROCKII pathway in experimental rats after middle cerebral artery occlusion (MCAO) and in SH-SY5Y cells exposed to oxygen-glucose deprivation/reperfusion (OGD/R). MATERIALS AND METHODS: Rats with permanent MCAO were administered XST, Y27632, XST plus Y27632, and nimodipine for 14 and 28 days. Successful MCAO onset was confirmed by 2,3,5-triphenyl tetrazolium chloride (TTC) staining. Neurological deficit score (NDS) was used to assess neurological impairment. Hematoxylin-eosin (HE) staining and immunohistochemical (IHC) analysis of synaptophysin (SYN) and postsynaptic density protein-95 (PSD-95) were performed to evaluate cerebral ischemic injury and the neuroprotective capability of XST. Nogo-A levels and the ROCKII pathway were detected by IHC analysis, western blotting, and quantitative real-time polymerase chain reaction (qRT-PCR) to explore the protective mechanism of XST. OGD/R model was established in SH-SY5Y cells. Cell counting kit 8 (CCK8) was applied to detect the optimum OGD time and XST concentration. The expression levels Nogo-A and ROCKII pathway were determined using western blotting. RESULTS: Our results showed that XST reduced neurological dysfunction and pathological damage, promoted weight gain and synaptic regeneration, reduced Nogo-A mRNA and protein levels, and inhibited the ROCKII pathway in MCAO rats. CCK8 assay displayed that the optimal OGD time and optimal XST concentration were 7 h and 20 µg/mL respectively in SH-SY5Y cells. XST could evidently inhibit OGD/R-induced Nogo-A protein expression and ROCKII pathway activation in SH-SY5Y cells. CONCLUSIONS: The present study suggested that XST exerted long-term neuroprotective effects that assisted in stroke recovery, possibly through inhibition of the ROCKII pathway.


Assuntos
Medicamentos de Ervas Chinesas/farmacologia , Infarto da Artéria Cerebral Média/tratamento farmacológico , Fármacos Neuroprotetores/farmacologia , Saponinas/farmacologia , Quinases Associadas a rho/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Proteína 4 Homóloga a Disks-Large/metabolismo , Medicamentos de Ervas Chinesas/uso terapêutico , Humanos , Infarto da Artéria Cerebral Média/metabolismo , Infarto da Artéria Cerebral Média/patologia , Masculino , Neuroproteção/efeitos dos fármacos , Fármacos Neuroprotetores/uso terapêutico , Proteínas Nogo/antagonistas & inibidores , Proteínas Nogo/genética , Proteínas Nogo/metabolismo , Panax notoginseng/química , Ratos Sprague-Dawley , Traumatismo por Reperfusão/tratamento farmacológico , Saponinas/uso terapêutico , Transdução de Sinais/efeitos dos fármacos , Acidente Vascular Cerebral/tratamento farmacológico , Sinaptofisina/metabolismo , Fatores de Tempo , Proteínas rho de Ligação ao GTP/genética , Proteínas rho de Ligação ao GTP/metabolismo
6.
Artigo em Inglês | MEDLINE | ID: mdl-32802113

RESUMO

OBJECTIVE: This study investigated whether Panax notoginseng saponins (PNS) extracted from Panax notoginseng (Bruk.) F. H. Chen played a neuroprotective role by affecting the EGFR/PI3K/AKT pathway in oxygen-glucose deprived (OGD) SH-SY5Y cells. MATERIALS AND METHODS: Different groups of OGD SH-SY5Y cells were treated with varying doses of PNS, PNS + AG1478 (a specific inhibitor of EGFR), or AG1478 for 16 hours. CCK8, Annexin V-FITC/PI apoptosis analysis, and LDH release analysis were used to determine cell viability, apoptosis rate, and amounts of LDH. Quantitative real-time PCR (q-RT-PCR) and western blotting were used to measure mRNA and proteins levels of p-EGFR/EGFR, p-PI3K/PI3K, and p-AKT/AKT in SH-SY5Y cells subjected to OGD. RESULTS: PNS significantly enhanced cell viability, reduced apoptosis, and weakened cytotoxicity by inhibiting the release of LDH. The mRNA expression profiles of EGFR, PI3K, and AKT showed no difference between model and other groups. Additionally, ratios of p-EGFR, p-PI3K, and p-AKT to EGFR, PI3K, and AKT proteins expression, respectively, all increased significantly. CONCLUSIONS: These findings indicate that PNS enhanced neuroprotective effects by activating the EGFR/PI3K/AKT pathway and elevating phosphorylation levels in OGD SH-SY5Y cells.

7.
Fungal Biol ; 122(6): 410-419, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29801784

RESUMO

Nitrogen starvation can induce cellular triacylglycerol (TAG) accumulation in different organisms with an unclear mechanism. In this study, we performed nutrient starvation and lipid droplet (LD) proteomics analyses of the filamentous fungus Metarhizium robertsii. Our results indicated that nitrogen starvation activated cell autophagic activity but inhibited the internalization of LDs into vacuoles for degradation. LD proteomic analyses identified an array of differentially accumulated proteins including autophagy-related (ATG) proteins, heat shock proteins, TAG metabolic and phospholipid biosynthetic enzymes when the fungus was grown in different nutrient conditions. In contrast to the highly activated MrATG8, the ATG proteins involved in vacuolar LD internalization were down-regulated after nitrogen starvation. Cellular TAG contents were increased in different ATG-gene null mutants of M. robertsii. In addition, TAG increase could be due to the up-regulation of TAG biogenesis along with the down-regulation of TAG catabolic enzymes in fungal cells after nitrogen deprivation. The data of this study benefit our understanding of the mechanism of nitrogen starvation induced TAG increase in different cells.


Assuntos
Autofagia , Gotículas Lipídicas/metabolismo , Metarhizium/metabolismo , Nitrogênio/deficiência , Estresse Fisiológico , Triglicerídeos/metabolismo , Proteínas Relacionadas à Autofagia/metabolismo , Vias Biossintéticas , Regulação para Baixo , Proteínas de Choque Térmico/metabolismo , Metarhizium/crescimento & desenvolvimento , Proteômica/métodos , Triglicerídeos/biossíntese , Triglicerídeos/genética , Regulação para Cima
8.
Environ Microbiol ; 20(1): 293-304, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-29159973

RESUMO

Phosphatidylcholine (PC) plays an important role in maintaining membrane integrity and functionality. In this study, two key genes (Mrpct and Mrpem) putatively involved in the cytidine diphosphate (CDP)-choline and phosphatidylethanolamine N-methyltransferase (PEMT) pathways for PC biosynthesis were characterized in the insect pathogenic fungus Metarhizium robertsii. The results indicated that disruption of Mrpct did not lead to any reduction of total PC content but impaired fungal virulence and increased cellular accumulation of triacylglycerol. Deletion of Mrpem reduced PC content and impaired fungal conidiation and infection structure differentiation but did not result in virulence defects. Lipidomic analysis revealed that deletion of Mrpct and Mrpem resulted in dissimilar effects on increase and decrease of PC moieties and other phospholipid species accumulations. Interestingly, we found that these two genes played opposite roles in activation of cell autophagy when the fungi were grown in a nutrient-rich medium. The connection between PC metabolism and autophagy was confirmed because PC content was drastically reduced in Mratg8Δ and that the addition of PC could rescue null mutant sporulation defect. The results of this study facilitate the understanding of PC metabolism on fungal physiology.


Assuntos
Autofagia/genética , Citidina Difosfato Colina/genética , Metarhizium/genética , Metarhizium/metabolismo , Fosfatidilcolinas/biossíntese , Fosfatidiletanolamina N-Metiltransferase/genética , Animais , Citidina Difosfato Colina/metabolismo , Proteínas Fúngicas/genética , Deleção de Genes , Genes Fúngicos/genética , Homeostase , Insetos/microbiologia , Metabolismo dos Lipídeos/genética , Fosfatidiletanolamina N-Metiltransferase/metabolismo , Fosfolipídeos/metabolismo , Virulência/genética
9.
PLoS Pathog ; 13(9): e1006604, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28873459

RESUMO

The lysin motif (LysM) containing proteins can bind chitin and are ubiquitous in various organisms including fungi. In plant pathogenic fungi, a few LysM proteins have been characterized as effectors to suppress chitin-induced immunity in plant hosts and therefore contribute to fungal virulence. The effector mechanism is still questioned in fungus-animal interactions. In this study, we found that LysM proteins are also present in animal pathogenic fungi and have evolved divergently. The genome of the insect pathogen Beauveria bassiana encodes 12 LysM proteins, and the genes were differentially transcribed by the fungus when grown in different conditions. Deletion of six genes that were expressed by the fungus growing in insects revealed that two, Blys2 and Blys5, were required for full fungal virulence. Both proteins could bind chitin and Blys5 (containing two LysM domains) could additionally bind chitosan and cellulose. Truncation analysis of Blys2 (containing five LysM domains) indicated that the combination of LysM domains could determine protein-binding affinity and specificity for different carbohydrates. Relative to the wild-type strain, loss of Blys2 or Blys5 could impair fungal propagation in insect hemocoels and lead to the upregulation of antifungal gene in insects. Interestingly, the virulence defects of ΔBlys2 and ΔBlys5 could be fully restored by complementation with the Slp1 effector from the rice blast fungus Magnaporthe oryzae. In contrast to Slp1 and Blys2, Blys5 could potentially protect fungal hyphae against chitinase hydrolysis. The results of this study not only advance the understanding of LysM protein evolution but also establish the effector mechanism of fungus-animal interactions.


Assuntos
Beauveria/imunologia , Genes Fúngicos/imunologia , Magnaporthe/imunologia , Mucoproteínas/isolamento & purificação , Magnaporthe/genética , Virulência
10.
BMC Genomics ; 18(1): 668, 2017 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-28854898

RESUMO

BACKGROUND: Ascomycete Cordyceps species have been using as valued traditional Chinese medicines. Particularly, the fruiting bodies of Cordyceps cicadae (syn. Isaria cicadae) have long been utilized for the treatment of chronic kidney disease. However, the genetics and bioactive chemicals in this fungus have been largely unexplored. RESULTS: In this study, we performed comprehensive omics analyses of C. cicadae, and found that, in contrast to other Cordyceps fungi, C. cicadae produces asexual fruiting bodies with the production of conidial spores instead of the meiotic ascospores. Genome sequencing and comparative genomic analysis indicate that the protein families encoded by C. cicadae are typical of entomopathogenic fungi, including the expansion of proteases and chitinases for targeting insect hosts. Interestingly, we found that the MAT1-2 mating-type locus of the sequenced strain contains an abnormally truncated MAT1-1-1 gene. Gene deletions revealed that asexual fruiting of C. cicadae is independent of the MAT locus control. RNA-seq transcriptome data also indicate that, compared to growth in a liquid culture, the putative genes involved in mating and meiosis processes were not up-regulated during fungal fruiting, further supporting asexual reproduction in this fungus. The genome of C. cicadae encodes an array of conservative and divergent gene clusters for secondary metabolisms. Based on our analysis, the production of known carcinogenic metabolites by this fungus could be potentially precluded. However, the confirmed production of oosporein raises health concerns about the frequent consumption of fungal fruiting bodies. CONCLUSIONS: The results of this study expand our knowledge of fungal genetics that asexual fruiting can occur independent of the MAT locus control. The obtained genomic and metabolomic data will benefit future investigations of this fungus for medicinal uses.


Assuntos
Cordyceps/genética , Cordyceps/metabolismo , Carpóforos/genética , Perfilação da Expressão Gênica , Metabolômica , Cordyceps/crescimento & desenvolvimento , Cordyceps/fisiologia , Evolução Molecular , Carpóforos/crescimento & desenvolvimento , Deleção de Genes , Loci Gênicos/genética , Família Multigênica/genética , Filogenia , Reprodução Assexuada/genética , Sintenia
11.
Genome Biol Evol ; 8(5): 1374-87, 2016 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-27071652

RESUMO

Fungal pathogens of plants and animals have multifarious effects; they cause devastating damages to agricultures, lead to life-threatening diseases in humans, or induce beneficial effects by reducing insect pest populations. Many virulence factors have been determined in different fungal pathogens; however, the molecular determinants contributing to fungal host selection and adaptation are largely unknown. In this study, we sequenced the genomes of seven ascomycete insect pathogens and performed the genome-wide analyses of 33 species of filamentous ascomycete pathogenic fungi that infect insects (12 species), plants (12), and humans (9). Our results revealed that the genomes of plant pathogens encode more proteins and protein families than the insect and human pathogens. Unexpectedly, more common orthologous protein groups are shared between the insect and plant pathogens than between the two animal group pathogens. We also found that the pathogenicity of host-adapted fungi evolved multiple times, and that both divergent and convergent evolutions occurred during pathogen-host cospeciation thus resulting in protein families with similar features in each fungal group. However, the role of phylogenetic relatedness on the evolution of protein families and therefore pathotype formation could not be ruled out due to the effect of common ancestry. The evolutionary correlation analyses led to the identification of different protein families that correlated with alternate pathotypes. Particularly, the effector-like proteins identified in plant and animal pathogens were strongly linked to fungal host adaptation, suggesting the existence of similar gene-for-gene relationships in fungus-animal interactions that has not been established before. These results well advance our understanding of the evolution of fungal pathogenicity and the factors that contribute to fungal pathotype formation.


Assuntos
Ascomicetos/genética , Evolução Molecular , Plantas/genética , Fatores de Virulência/genética , Animais , Ascomicetos/patogenicidade , Genoma Fúngico , Humanos , Insetos/microbiologia , Doenças das Plantas/genética , Doenças das Plantas/microbiologia , Plantas/microbiologia , Virulência/genética
12.
Proc Natl Acad Sci U S A ; 112(36): 11365-70, 2015 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-26305932

RESUMO

Quinones are widely distributed in nature and exhibit diverse biological or pharmacological activities; however, their biosynthetic machineries are largely unknown. The bibenzoquinone oosporein was first identified from the ascomycete insect pathogen Beauveria bassiana>50 y ago. The toxin can also be produced by different plant pathogenic and endophytic fungi with an array of biological activities. Here, we report the oosporein biosynthetic machinery in fungi, a polyketide synthase (PKS) pathway including seven genes for quinone biosynthesis. The PKS oosporein synthase 1 (OpS1) produces orsellinic acid that is hydroxylated to benzenetriol by the hydroxylase OpS4. The intermediate is oxidized either nonenzymatically to 5,5'-dideoxy-oosporein or enzymatically to benzenetetrol by the putative dioxygenase OpS7. The latter is further dimerized to oosporein by the catalase OpS5. The transcription factor OpS3 regulates intrapathway gene expression. Insect bioassays revealed that oosporein is required for fungal virulence and acts by evading host immunity to facilitate fungal multiplication in insects. These results contribute to the known mechanisms of quinone biosynthesis and the understanding of small molecules deployed by fungi that interact with their hosts.


Assuntos
Beauveria/metabolismo , Benzoquinonas/metabolismo , Proteínas Fúngicas/metabolismo , Policetídeo Sintases/metabolismo , Animais , Sequência de Bases , Beauveria/genética , Beauveria/imunologia , Benzoquinonas/análise , Cromatografia Líquida de Alta Pressão , Proteínas Fúngicas/genética , Ordem dos Genes , Interações Hospedeiro-Patógeno/imunologia , Evasão da Resposta Imune/imunologia , Isoenzimas/classificação , Isoenzimas/genética , Isoenzimas/metabolismo , Larva/imunologia , Larva/microbiologia , Mariposas/imunologia , Mariposas/microbiologia , Família Multigênica/genética , Mutação , Micotoxinas/análise , Micotoxinas/biossíntese , Filogenia , Policetídeo Sintases/classificação , Policetídeo Sintases/genética , Homologia de Sequência do Ácido Nucleico , Espectrometria de Massas em Tandem , Virulência/genética , Virulência/imunologia
13.
J Biol Chem ; 290(13): 8218-31, 2015 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-25673695

RESUMO

Transcription factors (TFs) containing the basic leucine zipper (bZIP) domain are widely distributed in eukaryotes and display an array of distinct functions. In this study, a bZIP-type TF gene (MBZ1) was deleted and functionally characterized in the insect pathogenic fungus Metarhizium robertsii. The deletion mutant (ΔMBZ1) showed defects in cell wall integrity, adhesion to hydrophobic surfaces, and topical infection of insects. Relative to the WT, ΔMBZ1 was also impaired in growth and conidiogenesis. Examination of putative target gene expression indicated that the genes involved in chitin biosynthesis were differentially transcribed in ΔMBZ1 compared with the WT, which led to the accumulation of a higher level of chitin in mutant cell walls. MBZ1 exhibited negative regulation of subtilisin proteases, but positive control of an adhesin gene, which is consistent with the observation of effects on cell autolysis and a reduction in spore adherence to hydrophobic surfaces in ΔMBZ1. Promoter binding assays indicated that MBZ1 can bind to different target genes and suggested the possibility of heterodimer formation to increase the diversity of the MBZ1 regulatory network. The results of this study advance our understanding of the divergence of bZIP-type TFs at both intra- and interspecific levels.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/fisiologia , Parede Celular/metabolismo , Proteínas Fúngicas/fisiologia , Metarhizium/fisiologia , Esporos Fúngicos/fisiologia , Animais , Sequência de Bases , Sítios de Ligação , Bombyx/microbiologia , DNA Fúngico/genética , Expressão Gênica , Regulação Fúngica da Expressão Gênica , Interações Hidrofóbicas e Hidrofílicas , Larva/microbiologia , Metarhizium/patogenicidade , Filogenia , Regiões Promotoras Genéticas , Ligação Proteica , Esporos Fúngicos/patogenicidade , Ativação Transcricional , Virulência
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