RESUMO
OBJECTIVE: This study aims to explore the prevalence, characteristics, and psychopathology related to Problematic Use of Internet (PUI), including Internet Addiction (IA), within a sample of psychiatric outpatients. METHODS: 143 psychiatric stable outpatients (18-65, mean age: 49; F=84) were included in this study, regardless of their categorical diagnosis. Socio-demographic, clinical, psychopathological, and Internet use-related data (PIU-Scale, Internet Addiction Test, devices, use, activities) were collected across the sample. RESULTS: The prevalence of PUI ranged between 1% (IAT) and 25% (PIU-S), with a homogeneous distribution of PUI symptoms' severity among the four main psychopathological areas (depressive, bipolar, anxiety, and psychotic disorders). PUI was correlated with age and was higher in students as in the general population. Significant associations were found between PUI symptoms and both personality and eating disorders; PUI was also positively correlated with the presence of other addictions (e.g., alcohol and/or substances). A greater proportion of patients with PUI presented other forms of behavioural addiction compared to non-symptomatic patients. Social media and online shopping, as well as video-streaming, resulted to be the main forms of PUI among patients with problematic use of the Internet. DISCUSSION: More studies are required among students diagnosed with eating and personality disorders. The association between PUI and other addictive disorders would support the hypothesis of their common shared pathophysiology. CONCLUSION: Healthcare providers and educators should be made aware of such risks. More studies are needed to confirm such preliminary findings.
Assuntos
Transtorno de Adição à Internet , Pacientes Ambulatoriais , Humanos , Adulto , Masculino , Feminino , Pessoa de Meia-Idade , Prevalência , Adolescente , Adulto Jovem , Transtorno de Adição à Internet/epidemiologia , Transtorno de Adição à Internet/psicologia , Idoso , Pacientes Ambulatoriais/estatística & dados numéricos , Internet , Transtornos da Alimentação e da Ingestão de Alimentos/epidemiologia , Comportamento Aditivo/epidemiologia , Comportamento Aditivo/psicologia , Transtornos Psicóticos/epidemiologia , Transtornos Mentais/epidemiologia , Itália/epidemiologia , Transtorno Bipolar/epidemiologia , Transtornos de Ansiedade/epidemiologiaRESUMO
BACKGROUND: Liquid biopsies and the dynamic tracking of somatic mutations within circulating tumour DNA (ctDNA) can provide insight into the dynamics of cancer evolution and the intra-tumour heterogeneity that fuels treatment resistance. However, identifying and tracking dynamic changes in somatic copy number alterations (SCNAs), which have been associated with poor outcome and metastasis, using ctDNA is challenging. Pancreatic adenocarcinoma is a disease which has been considered to harbour early punctuated events in its evolution, leading to an early fitness peak, with minimal further subclonal evolution. METHODS: To interrogate the role of SCNAs in pancreatic adenocarcinoma cancer evolution, we applied whole-exome sequencing of 55 longitudinal cell-free DNA (cfDNA) samples taken from 24 patients (including 8 from whom a patient-derived xenograft (PDX) was derived) with metastatic disease prospectively recruited into a clinical trial. We developed a method, Aneuploidy in Circulating Tumour DNA (ACT-Discover), that leverages haplotype phasing of paired tumour biopsies or PDXs to identify SCNAs in cfDNA with greater sensitivity. RESULTS: SCNAs were observed within 28 of 47 evaluable cfDNA samples. Of these events, 30% could only be identified by harnessing the haplotype-aware approach leveraged in ACT-Discover. The exceptional purity of PDX tumours enabled near-complete phasing of genomic regions in allelic imbalance, highlighting an important auxiliary function of PDXs. Finally, although the classical model of pancreatic cancer evolution emphasises the importance of early, homogenous somatic events as a key requirement for cancer development, ACT-Discover identified substantial heterogeneity of SCNAs, including parallel focal and arm-level events, affecting different parental alleles within individual tumours. Indeed, ongoing acquisition of SCNAs was identified within tumours throughout the disease course, including within an untreated metastatic tumour. CONCLUSIONS: This work demonstrates the power of haplotype phasing to study genomic variation in cfDNA samples and reveals undiscovered intra-tumour heterogeneity with important scientific and clinical implications. Implementation of ACT-Discover could lead to important insights from existing cohorts or underpin future prospective studies seeking to characterise the landscape of tumour evolution through liquid biopsy.
Assuntos
Adenocarcinoma , Ácidos Nucleicos Livres , DNA Tumoral Circulante , Neoplasias Pancreáticas , Humanos , DNA Tumoral Circulante/genética , Adenocarcinoma/genética , Neoplasias Pancreáticas/genética , Estudos Prospectivos , Cariótipo , Mutação , Biomarcadores Tumorais/genéticaRESUMO
Despite the progress in cardiovascular research, atherosclerosis still represents the main cause of death worldwide. Clinically, the diagnosis of Atherosclerotic Cardiovascular Disease (ASCVD) relies on imaging methodologies including X-ray angiography and computed tomography (CT), which however still fails in the identification of patients at high risk of plaque rupture, the main cause of severe clinical events as stroke and heart attack. Magnetic resonance imaging, which is characterized by very high spatial resolution, could provide a better characterization of atherosclerotic plaque (AP) anatomy and composition, aiding in the identification of "vulnerable" plaques. In this context, hydrogel matrices, which have been demonstrated able to boost relaxometric properties of Gd-based contrast agents (CAs) by the effect of Hydrodenticity, represent a valuable tool towards the precision imaging of ASCVD improving the performance of this class of CAs while reducing systemic toxicity. In particular, hydrogel nanoparticles encapsulating Gd-DTPA can further contribute to providing CA-specific accumulation in the AP by nanoparticle surface decoration triggering an active targeting of the AP with the overall effect of allowing an earlier and more accurate diagnosis. In this work, we tested crosslinked Hyaluronic Acid Nanoparticles (cHANPs) in the complex environment of human atherosclerotic plaque. In addition, the surface of cHANPs was decorated with the antibody anti-CD36 (Ab36-cHANPs) for the active targeting of AP-associated macrophages. Results demonstrate that the Hydrodenticity of cHANPs and Ab36-cHANPs is preserved in this complex system and, preliminarily, that interaction of these probes with the AP is present.
Assuntos
Aterosclerose/diagnóstico por imagem , Imageamento por Ressonância Magnética , Nanopartículas/química , Placa Aterosclerótica/diagnóstico por imagem , Aterosclerose/diagnóstico , Aterosclerose/patologia , Meios de Contraste/química , Meios de Contraste/farmacologia , Gadolínio DTPA/farmacologia , Humanos , Ácido Hialurônico/química , Ácido Hialurônico/farmacologia , Macrófagos/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Placa Aterosclerótica/patologiaRESUMO
Purpose: Despite the wide use of antiangiogenic drugs in the clinical setting, predictive biomarkers of response to these drugs are still unknown.Experimental Design: We applied whole-exome sequencing of matched germline and basal plasma cell-free DNA samples (WES-cfDNA) on a RAS/BRAF/PIK3CA wild-type metastatic colorectal cancer patient with primary resistance to standard treatment regimens, including inhibitors to the VEGF:VEGFR2 pathway. We performed extensive functional experiments, including ectopic expression of VEGFR2 mutants in different cell lines, kinase and drug sensitivity assays, and cell- and patient-derived xenografts.Results: WES-cfDNA yielded a 77% concordance rate with tumor exome sequencing and enabled the identification of the KDR/VEGFR2 L840F clonal, somatic mutation as the cause of therapy refractoriness in our patient. In addition, we found that 1% to 3% of samples from cancer sequencing projects harbor KDR somatic mutations located in protein residues frequently mutated in other cancer-relevant kinases, such as EGFR, ABL1, and ALK. Our in vitro and in vivo functional assays confirmed that L840F causes strong resistance to antiangiogenic drugs, whereas the KDR hot-spot mutant R1032Q confers sensitivity to strong VEGFR2 inhibitors. Moreover, we showed that the D717V, G800D, G800R, L840F, G843D, S925F, R1022Q, R1032Q, and S1100F VEGFR2 mutants promote tumor growth in mice.Conclusions: Our study supports WES-cfDNA as a powerful platform for portraying the somatic mutation landscape of cancer and discovery of new resistance mechanisms to cancer therapies. Importantly, we discovered that VEGFR2 is somatically mutated across tumor types and that VEGFR2 mutants can be oncogenic and control sensitivity/resistance to antiangiogenic drugs. Clin Cancer Res; 24(15); 3550-9. ©2018 AACR.
Assuntos
Inibidores da Angiogênese/administração & dosagem , Neoplasias Colorretais/genética , Neovascularização Patológica/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/genética , Quinase do Linfoma Anaplásico/genética , Inibidores da Angiogênese/efeitos adversos , Animais , Biomarcadores Tumorais/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Ácidos Nucleicos Livres/sangue , Ácidos Nucleicos Livres/genética , Classe I de Fosfatidilinositol 3-Quinases/genética , Neoplasias Colorretais/sangue , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Receptores ErbB/genética , Exoma/genética , Feminino , Xenoenxertos , Humanos , Camundongos , Mutação , Neovascularização Patológica/sangue , Neovascularização Patológica/tratamento farmacológico , Neovascularização Patológica/patologia , Conformação Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-abl/genética , Fator A de Crescimento do Endotélio Vascular/genética , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/sangue , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/química , Sequenciamento do ExomaRESUMO
Cancer genomics and translational medicine rely on the molecular profiling of patient's tumor obtained during surgery or biopsy. Alternatively, blood is a less invasive source of tumor DNA shed, amongst other ways, as cell-free DNA (cfDNA). Highly-sensitive assays capable to detect cancer genetic events from patient's blood plasma became popularly known as liquid biopsy (LqB). Importantly, retrospective studies including small number of selected patients with metastatic colorectal cancer (mCRC) patients treated with anti-EGFR therapy have shown LqB capable to detect the acquired clonal mutations in RAS genes leading to therapy resistance. However, the usefulness of LqB in the real-life clinical monitoring of these patients still lack additional validation on controlled studies. In this context, we designed a prospective LqB clinical trial to monitor newly diagnosed KRAS wild-type (wt) mCRC patients who received a standard FOLFIRI-cetuximab regimen. We used BEAMing technique for evaluate cfDNA mutations in KRAS, NRAS, BRAF, and PIK3CA in twenty-five patients during a 2-y period. A total of 2,178 cfDNA mutation analyses were performed and we observed that: a) continued wt circulating status was correlated with a prolonged response; b) smoldering increases in mutant cfDNA were correlated with acquired resistance; while c) mutation upsurge/explosion anticipated a remarkable clinical deterioration. The current study provides evidences, obtained for the first time in an unbiased and prospective manner, that reinforces the utility of LqB for monitoring mCRC patients.
Assuntos
Antineoplásicos Imunológicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Camptotecina/análogos & derivados , Cetuximab/uso terapêutico , Neoplasias Colorretais/patologia , Análise Mutacional de DNA/métodos , Proteínas ras/genética , Camptotecina/uso terapêutico , Classe I de Fosfatidilinositol 3-Quinases/genética , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Feminino , Fluoruracila/uso terapêutico , GTP Fosfo-Hidrolases/genética , Humanos , Leucovorina/uso terapêutico , Biópsia Líquida , Masculino , Proteínas de Membrana/genética , Metástase Neoplásica , Estudos Prospectivos , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Análise de Sobrevida , Resultado do TratamentoRESUMO
We explored whether the combination of lurbinectedin (PM01183) with the antimetabolite gemcitabine could result in a synergistic antitumor effect in pancreatic ductal adenocarcinoma (PDA) mouse models. We also studied the contribution of lurbinectedin to this synergism. This drug presents a dual pharmacological effect that contributes to its in vivo antitumor activity: (i) specific binding to DNA minor grooves, inhibiting active transcription and DNA repair; and (ii) specific depletion of tumor-associated macrophages (TAMs). We evaluated the in vivo antitumor activity of lurbinectedin and gemcitabine as single agents and in combination in SW-1990 and MIA PaCa-2 cell-line xenografts and in patient-derived PDA models (AVATAR). Lurbinectedin-gemcitabine combination induced a synergistic effect on both MIA PaCa-2 [combination index (CI)=0.66] and SW-1990 (CI=0.80) tumor xenografts. It also induced complete tumor remissions in four out of six patient-derived PDA xenografts. This synergism was associated with enhanced DNA damage (anti-γ-H2AX), cell cycle blockage, caspase-3 activation and apoptosis. In addition to the enhanced DNA damage, which is a consequence of the interaction of the two drugs with the DNA, lurbinectedin induced TAM depletion leading to cytidine deaminase (CDA) downregulation in PDA tumors. This effect could, in turn, induce an increase of gemcitabine-mediated DNA damage that was especially relevant in high-density TAM tumors. These results show that lurbinectedin can be used to develop 'molecularly targeted' combination strategies.
Assuntos
Adenocarcinoma/tratamento farmacológico , Carbolinas/uso terapêutico , Desoxicitidina/análogos & derivados , Compostos Heterocíclicos de 4 ou mais Anéis/uso terapêutico , Macrófagos/patologia , Neoplasias Pancreáticas/tratamento farmacológico , Adenocarcinoma/patologia , Animais , Apoptose/efeitos dos fármacos , Carbolinas/farmacologia , Caspase 3/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Citidina Desaminase/metabolismo , Dano ao DNA , Desoxicitidina/farmacologia , Desoxicitidina/uso terapêutico , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Sinergismo Farmacológico , Ativação Enzimática/efeitos dos fármacos , Feminino , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Humanos , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Camundongos Nus , Neoplasias Pancreáticas/patologia , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto , Gencitabina , Neoplasias PancreáticasRESUMO
The gene doublesex, which is placed at the bottom of the sex-determination gene cascade, plays the ultimate discriminatory role for sex determination in insects. In all insects where this gene has been characterized, the dsx premessenger RNA (pre-mRNA) follows a sex-specific splicing pattern, producing male- and female-specific mRNAs encoding the male-DSXM and female-DSXF proteins, which determine male and female development, respectively. This article reports the isolation and characterization of the gene doublesex of dipteran Sciara insects. The Sciara doublesex gene is constitutively transcribed during development and adult life of males and females. Sciara had no sex-specific doublesex mRNAs but the same transcripts, produced by alternative splicing of its primary transcript, were present in both sexes, although their relative abundance is sex specific. However, only the female DSXF protein, but not the male DSXM protein, was produced at similar amounts in both sexes. An analysis of the expression of female and male Sciara DSX proteins in Drosophila showed that these proteins conserved female and male function, respectively, on the control of Drosophila yolk-protein genes. The molecular evolution of gene doublesex of all insects where this gene has been characterized revealed that Sciara doublesex displays a considerable degree of divergence in its molecular organization and its splicing pattern with respect to the rest of dipterans as suggested by its basal position within the doublesex phylogeny. It is suggested that the doublesex gene is involved in Sciara sex determination although it appears not to play the discriminatory role performed in other insects.
Assuntos
Dípteros/genética , Dípteros/metabolismo , Proteínas de Insetos/metabolismo , Processos de Determinação Sexual , Animais , Proteínas de Drosophila/genética , Feminino , Regulação da Expressão Gênica , Proteínas de Insetos/genética , Masculino , Filogenia , Splicing de RNA , RNA Mensageiro/genética , RNA Mensageiro/metabolismoRESUMO
A current pressing need in cancer immunology is the development of preclinical model systems that are immunocompetent for the study of human tumors. Here, we report the development of a humanized murine model that can be used to analyze the pharmacodynamics and antitumor properties of immunostimulatory monoclonal antibodies (mAb) in settings where the receptors targeted by the mAbs are expressed. Human lymphocytes transferred into immunodeficient mice underwent activation and redistribution to murine organs, where they exhibited cell-surface expression of hCD137 and hPD-1. Systemic lymphocyte infiltrations resulted in a lethal CD4(+) T cell-mediated disease (xenograft-versus-host disease), which was aggravated when murine subjects were administered clinical-grade anti-hCD137 (urelumab) and anti-hPD-1 (nivolumab). In mice engrafted with human colorectal HT-29 carcinoma cells and allogeneic human peripheral blood mononuclear cells (PBMC), or with a patient-derived gastric carcinoma and PBMCs from the same patient, we found that coadministration of urelumab and nivolumab was sufficient to significantly slow tumor growth. Correlated with this result were increased numbers of activated human T lymphocytes producing IFNγ and decreased numbers of human regulatory T lymphocytes in the tumor xenografts, possibly explaining the efficacy of the therapeutic regimen. Our results offer a proof of concept for the use of humanized mouse models for surrogate efficacy and histology investigations of immune checkpoint drugs and their combinations.
Assuntos
Neoplasias Colorretais/imunologia , Proteínas de Ligação a DNA/genética , Subunidade gama Comum de Receptores de Interleucina/genética , Receptor de Morte Celular Programada 1/biossíntese , Linfócitos T/efeitos dos fármacos , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/biossíntese , Animais , Anticorpos Monoclonais/administração & dosagem , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Proteínas de Ligação a DNA/imunologia , Doença Enxerto-Hospedeiro/imunologia , Doença Enxerto-Hospedeiro/patologia , Células HT29 , Humanos , Subunidade gama Comum de Receptores de Interleucina/imunologia , Leucócitos Mononucleares/imunologia , Ativação Linfocitária/imunologia , Camundongos , Nivolumabe , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Receptor de Morte Celular Programada 1/imunologia , Linfócitos T/patologia , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/antagonistas & inibidores , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologiaRESUMO
BACKGROUND: Current technology permits an unbiased massive analysis of somatic genetic alterations from tumor DNA as well as the generation of individualized mouse xenografts (Avatar models). This work aimed to evaluate our experience integrating these two strategies to personalize the treatment of patients with cancer. METHODS: We performed whole-exome sequencing analysis of 25 patients with advanced solid tumors to identify putatively actionable tumor-specific genomic alterations. Avatar models were used as an in vivo platform to test proposed treatment strategies. RESULTS: Successful exome sequencing analyses have been obtained for 23 patients. Tumor-specific mutations and copy-number variations were identified. All samples profiled contained relevant genomic alterations. Tumor was implanted to create an Avatar model from 14 patients and 10 succeeded. Occasionally, actionable alterations such as mutations in NF1, PI3KA, and DDR2 failed to provide any benefit when a targeted drug was tested in the Avatar and, accordingly, treatment of the patients with these drugs was not effective. To date, 13 patients have received a personalized treatment and 6 achieved durable partial remissions. Prior testing of candidate treatments in Avatar models correlated with clinical response and helped to select empirical treatments in some patients with no actionable mutations. CONCLUSION: The use of full genomic analysis for cancer care is encouraging but presents important challenges that will need to be solved for broad clinical application. Avatar models are a promising investigational platform for therapeutic decision making. While limitations still exist, this strategy should be further tested.
Assuntos
Sequenciamento de Nucleotídeos em Larga Escala , Terapia de Alvo Molecular , Neoplasias/tratamento farmacológico , Neoplasias/genética , Medicina de Precisão , Adulto , Idoso , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/uso terapêutico , Biologia Computacional , Variações do Número de Cópias de DNA , Modelos Animais de Doenças , Exoma , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/química , Feminino , Genômica , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Modelos Moleculares , Mutação , Neoplasias/patologia , Fosfatidilinositol 3-Quinases/química , Inibidores de Fosfoinositídeo-3 Quinase , Conformação Proteica , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/química , Estudos Retrospectivos , Resultado do Tratamento , Carga Tumoral , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: The Drosophila SXL protein controls sex determination and dosage compensation. It is a sex-specific factor controlling splicing of its own Sxl pre-mRNA (auto-regulation), tra pre-mRNA (sex determination) and msl-2 pre-mRNA plus translation of msl-2 mRNA (dosage compensation). Outside the drosophilids, the same SXL protein has been found in both sexes so that, in the non-drosophilids, SXL does not appear to play the key discriminating role in sex determination and dosage compensation that it plays in Drosophila. Comparison of SXL proteins revealed that its spatial organisation is conserved, with the RNA-binding domains being highly conserved, whereas the N- and C-terminal domains showing significant variation. This manuscript focuses on the evolution of the SXL protein itself and not on regulation of its expression. METHODOLOGY: Drosophila-Sciara chimeric SXL proteins were produced. Sciara SXL represents the non-sex-specific function of ancient SXL in the non-drosophilids from which presumably Drosophila SXL evolved. Two questions were addressed. Did the Drosophila SXL protein have affected their functions when their N- and C-terminal domains were replaced by the corresponding ones of Sciara? Did the Sciara SXL protein acquire Drosophila sex-specific functions when the Drosophila N- and C-terminal domains replaced those of Sciara? The chimeric SXL proteins were analysed in vitro to study their binding affinity and cooperative properties, and in vivo to analyse their effect on sex determination and dosage compensation by producing Drosophila flies that were transgenic for the chimeric SXL proteins. CONCLUSIONS: The sex-specific properties of extant Drosophila SXL protein depend on its global structure rather than on a specific domain. This implies that the modifications, mainly in the N- and C-terminal domains, that occurred in the SXL protein during its evolution within the drosophilid lineage represent co-evolutionary changes that determine the appropriate folding of SXL to carry out its sex-specific functions.
Assuntos
Mecanismo Genético de Compensação de Dose , Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Precursores de RNA/metabolismo , Splicing de RNA/genética , Proteínas de Ligação a RNA/metabolismo , Transgenes/fisiologia , Animais , Animais Geneticamente Modificados , Western Blotting , Drosophila/classificação , Drosophila/genética , Proteínas de Drosophila/genética , Ensaio de Desvio de Mobilidade Eletroforética , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Masculino , Estrutura Terciária de Proteína , Precursores de RNA/genética , RNA Mensageiro/genética , Proteínas de Ligação a RNA/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
The transformer-2 gene is involved in sex determination in tephritid flies (Tephritidae). It is required for the auto-regulation of the transformer gene (the memory device for sex determination in these insects) and for the female-specific splicing of doublesex pre-mRNA, the last gene in the sex determination gene cascade. The present manuscript addressed the question of the functional conservation of the tephritid Anastrepha Tra2 protein to direct sexual development in Drosophila (Drosophilidae). To express this protein in Drosophila, the GAL4-UAS system was used. The Anastrepha Tra2 protein supplies tra-2 function in Drosophila: this protein would form a complex with the endogenous Drosophila Tra protein to promote the female-specific splicing of the Drosophila doublesex pre-mRNA. The feminisation produced by the Anastrepha Tra2 protein was, however, partial.
Assuntos
Proteínas de Drosophila/fisiologia , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Ribonucleoproteínas/fisiologia , Tephritidae/genética , Tephritidae/fisiologia , Animais , Cruzamentos Genéticos , Feminino , Genótipo , Masculino , Modelos Genéticos , Precursores de RNA/genética , Análise de Sequência de DNA , Desenvolvimento Sexual/genética , Temperatura , TransgenesRESUMO
BACKGROUND: In the tephritids Ceratitis, Bactrocera and Anastrepha, the gene transformer provides the memory device for sex determination via its auto-regulation; only in females is functional Tra protein produced. To date, the isolation and characterisation of the gene transformer-2 in the tephritids has only been undertaken in Ceratitis, and it has been shown that its function is required for the female-specific splicing of doublesex and transformer pre-mRNA. It therefore participates in transformer auto-regulatory function. In this work, the characterisation of this gene in eleven tephritid species belonging to the less extensively analysed genus Anastrepha was undertaken in order to throw light on the evolution of transformer-2. RESULTS: The gene transformer-2 produces a protein of 249 amino acids in both sexes, which shows the features of the SR protein family. No significant partially spliced mRNA isoform specific to the male germ line was detected, unlike in Drosophila. It is transcribed in both sexes during development and in adult life, in both the soma and germ line. The injection of Anastrepha transformer-2 dsRNA into Anastrepha embryos caused a change in the splicing pattern of the endogenous transformer and doublesex pre-mRNA of XX females from the female to the male mode. Consequently, these XX females were transformed into pseudomales. The comparison of the eleven Anastrepha Transformer-2 proteins among themselves, and with the Transformer-2 proteins of other insects, suggests the existence of negative selection acting at the protein level to maintain Transformer-2 structural features. CONCLUSIONS: These results indicate that transformer-2 is required for sex determination in Anastrepha through its participation in the female-specific splicing of transformer and doublesex pre-mRNAs. It is therefore needed for the auto-regulation of the gene transformer. Thus, the transformer/transfomer-2 > doublesex elements at the bottom of the cascade, and their relationships, probably represent the ancestral state (which still exists in the Tephritidae, Calliphoridae and Muscidae lineages) of the extant cascade found in the Drosophilidae lineage (in which tra is just another component of the sex determination gene cascade regulated by Sex-lethal). In the phylogenetic lineage that gave rise to the drosophilids, evolution co-opted for Sex-lethal, modified it, and converted it into the key gene controlling sex determination.