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Changing the Pancreatic Cancer Treatment Paradigm: Developing Clostridium novyi as an Intravenously Injectable Solid-State Tumor TherapeuticDailey, Kaitlin Marie January 2020 (has links)
The development of a drug able to distinguish between tumor and host cells has been long sought, but the solid tumor microenvironment (TME) confounds many current therapeutics. Solid tumors present several challenges for oncotherapeutics, primarily, (1) aberrant vascularization, resulting in hypoxia, necrosis, abnormally high pH, and (2) tumor immune suppression. Oncolytic microbes are drawn to this microenvironment by an innate ability to selectively penetrate, colonize, and eradicate solid tumors as well as reactivate tumor associated immune components. To consider oncolytic bacteria deployment into this microenvironment, Chapter 1 dives into the background of oncolytic microbes. A discussion of the oncolytic bacterial field state, identifying Clostridium novyi? as a promising species, and details genetic engineering techniques to develop customized bacteria. Despite the promise of C.novyi in preclinical/clinical trials when administered intratumorally, the genetic and biochemical uniqueness of C.novyi necessitated the development of new methodologies to facilitate more widespread acceptance. Chapter 2 reports the development of methods that facilitate experimental work and therapeutic translation of C.novyi, including the ability to work with this obligate micro-anaerobe aerobically on the benchtop. While methods development is a necessary step in the clinical translation of C.novyi so too is choosing the correct model of the TME within which to test a potential anti-cancer therapy. While the typical solid TME includes both phenotypic and genotypic heterogeneity, the methods used to model this disease state often do not reflect this complexity. This simplistic approach may have contributed to stagnant five-year survival rates over the past four decades. Nevertheless, simplistic models are a necessary first step in clinical translation. Chapter 3 explores the impact of cancer cell lines co-cultured with C. novyi to establish the efficacy of this oncolytic bacteria in a monolayer culture. Chapter 4 extends this analysis adding not only a level of complexity by using an in vivo model, but also using CRISPR/Cas9 to modify the genome of C.novyi to encode a tumor targeting peptide, RGD, for expression within the spore coat. The combination of these studies indicates that C. novyi is uniquely poised to accomplish the long sought after selective tumor localization via intravenous delivery.
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Ruggero Jacobbi crítico-tradutor de poesia brasileira: da Litania dos Pobres à Invenzione di Orfeo / Ruggero Jacobbi critic-translator of Brazilian poetry: from the Litania dos Pobres to the Invenzione di OrfeoSilva, Daniel Souza da 07 December 2018 (has links)
Tendo atuado no meio artístico e intelectual brasileiro do segundo pós-guerra até o fim da década seguinte, o veneziano Ruggero Jacobbi (1920-1981) foi um destacado crítico, tradutor e difusor da literatura brasileira, especialmente do drama e da lírica. A pesquisa procura, na perspectiva dos Estudos Descritivos da Tradução, recorrer ao instrumental da crítica genética aplicado à grandiosa tradução Invenzione di Orfeo, trabalho que lhe teria tomado décadas de dedicação, a partir da obra maior do poeta nordestino Jorge de Lima. O levantamento de documentos em acervos na Itália permitiu a consolidação de um dossiê genético a partir do qual se discute o processo tradutório no bojo da atuação brasilianista de Jacobbi. Os nomes do poeta Murilo Mendes e da filóloga Luciana Stegagno Picchio surgem no estudo como frequentes coadjuvantes deste que talvez tenha sido o empreendimento mais ambicioso do amigo. Antes da reconstituição crítico-genética, no entanto, apresenta-se a fulgurante presença da obra lírica do poeta alagoano no distante país peninsular, desde a primeira figuração por obra de Giuseppe Ungaretti até as investidas exegéticas fundamentais de Stegagno Picchio. Para tanto, por sua vez, apresenta-se e se discute a trajetória geral, brasileira e, depois, brasilianista de Ruggero Jacobbi, com atenção ao legado relativo à lírica nacional, que culmina no objeto maior desta dissertação. Entre a teatralização engajada da Litania dos Pobres de Cruz e Sousa para uma montagem brechtiana apresentada no Teatro Brasileiro de Comédia (TBC) em 1950 e a publicação póstuma do grande exemplo de transcriação, guia-nos o espírito crítico marxista-gramsciano e impuro de um intelectual marcado pelo ecletismo e pela contundência inconformista, formado em meio aos herméticos florentinos da era fascista e movido a refratar sua expressão insone em poesia, em teatro, no cinema, no diário, no ensaio, na crítica, na historiografia literária, na antologia e na tradução. / Since the Venetian Ruggero Jacobbi (1920-1981) acted in the Brazilian artistic and intellectual world from the second postwar until the end of the next decade, he was an important literary critic, translator and diffuser of the Brazilian literature, especially of the drama and lyric poetry. This research aims, in the Descriptive Translation Studies perspective, to use tools from the genetic editing (critique génétique) and apply them to the magnificent translation Invenzione di Orfeo, which work supposedly took some decades of dedication, of the most important work of the Brazilian northeastern poet Jorge de Lima. The process of gathering documents in documentary archives in Italy allowed the make of a genetic dossier, with which it was possible to discuss the translation process, in the Brazilianist works of Jacobbi. The names of the poet Murilo Mendes and of the philologist Luciana Stegagno Picchio appeared in this research because they have shared with Jacobbi the experience of carrying out the most ambitious project of his professional life. Before of the critical-genetic reconstitution, however, there was the brightening glow: the reception of the poetic work of the Alagoan poet in the peninsular country, which includes since the first manifestation made by Giuseppe Ungaretti until the fundamental exegetical attempts of Stegagno Picchio. Before this phase, there was the presentation of the Brazilian and Brazilianist trajectory of Ruggero Jacobbi, and then the discussion on this subject, with special attention to his legacy to the national lyric poetry, which culminated on what, is the main object of this work. In the journey from the political dramatization of Litania dos Pobres (from the poem by Cruz e Sousa) into a Brechtian play presented in the Brazilian Comedy Theater (Teatro Brasileiro de Comédia TBC) in 1950, to the posthumous publication of the great example of transcreation, the guide to us is this impure and marxist-gramscian critic spirit of an intellectual marked by the eclecticism and by the nonconformist force, shaped between the hermetic Florentines of the fascist era, a spirit which was moved to reflect his insomniac expression in the poetry, in the drama, in the filmmaking, in the diaries, in the essays, in the literary criticism, in the literary historiography, in the anthology and in the translation.
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Ruggero Jacobbi crítico-tradutor de poesia brasileira: da Litania dos Pobres à Invenzione di Orfeo / Ruggero Jacobbi critic-translator of Brazilian poetry: from the Litania dos Pobres to the Invenzione di OrfeoDaniel Souza da Silva 07 December 2018 (has links)
Tendo atuado no meio artístico e intelectual brasileiro do segundo pós-guerra até o fim da década seguinte, o veneziano Ruggero Jacobbi (1920-1981) foi um destacado crítico, tradutor e difusor da literatura brasileira, especialmente do drama e da lírica. A pesquisa procura, na perspectiva dos Estudos Descritivos da Tradução, recorrer ao instrumental da crítica genética aplicado à grandiosa tradução Invenzione di Orfeo, trabalho que lhe teria tomado décadas de dedicação, a partir da obra maior do poeta nordestino Jorge de Lima. O levantamento de documentos em acervos na Itália permitiu a consolidação de um dossiê genético a partir do qual se discute o processo tradutório no bojo da atuação brasilianista de Jacobbi. Os nomes do poeta Murilo Mendes e da filóloga Luciana Stegagno Picchio surgem no estudo como frequentes coadjuvantes deste que talvez tenha sido o empreendimento mais ambicioso do amigo. Antes da reconstituição crítico-genética, no entanto, apresenta-se a fulgurante presença da obra lírica do poeta alagoano no distante país peninsular, desde a primeira figuração por obra de Giuseppe Ungaretti até as investidas exegéticas fundamentais de Stegagno Picchio. Para tanto, por sua vez, apresenta-se e se discute a trajetória geral, brasileira e, depois, brasilianista de Ruggero Jacobbi, com atenção ao legado relativo à lírica nacional, que culmina no objeto maior desta dissertação. Entre a teatralização engajada da Litania dos Pobres de Cruz e Sousa para uma montagem brechtiana apresentada no Teatro Brasileiro de Comédia (TBC) em 1950 e a publicação póstuma do grande exemplo de transcriação, guia-nos o espírito crítico marxista-gramsciano e impuro de um intelectual marcado pelo ecletismo e pela contundência inconformista, formado em meio aos herméticos florentinos da era fascista e movido a refratar sua expressão insone em poesia, em teatro, no cinema, no diário, no ensaio, na crítica, na historiografia literária, na antologia e na tradução. / Since the Venetian Ruggero Jacobbi (1920-1981) acted in the Brazilian artistic and intellectual world from the second postwar until the end of the next decade, he was an important literary critic, translator and diffuser of the Brazilian literature, especially of the drama and lyric poetry. This research aims, in the Descriptive Translation Studies perspective, to use tools from the genetic editing (critique génétique) and apply them to the magnificent translation Invenzione di Orfeo, which work supposedly took some decades of dedication, of the most important work of the Brazilian northeastern poet Jorge de Lima. The process of gathering documents in documentary archives in Italy allowed the make of a genetic dossier, with which it was possible to discuss the translation process, in the Brazilianist works of Jacobbi. The names of the poet Murilo Mendes and of the philologist Luciana Stegagno Picchio appeared in this research because they have shared with Jacobbi the experience of carrying out the most ambitious project of his professional life. Before of the critical-genetic reconstitution, however, there was the brightening glow: the reception of the poetic work of the Alagoan poet in the peninsular country, which includes since the first manifestation made by Giuseppe Ungaretti until the fundamental exegetical attempts of Stegagno Picchio. Before this phase, there was the presentation of the Brazilian and Brazilianist trajectory of Ruggero Jacobbi, and then the discussion on this subject, with special attention to his legacy to the national lyric poetry, which culminated on what, is the main object of this work. In the journey from the political dramatization of Litania dos Pobres (from the poem by Cruz e Sousa) into a Brechtian play presented in the Brazilian Comedy Theater (Teatro Brasileiro de Comédia TBC) in 1950, to the posthumous publication of the great example of transcreation, the guide to us is this impure and marxist-gramscian critic spirit of an intellectual marked by the eclecticism and by the nonconformist force, shaped between the hermetic Florentines of the fascist era, a spirit which was moved to reflect his insomniac expression in the poetry, in the drama, in the filmmaking, in the diaries, in the essays, in the literary criticism, in the literary historiography, in the anthology and in the translation.
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Edição genética d\'A gramatiquinha da fala brasileira de Mário de Andrade / The genetic edition of The little grammar of spoken Brazilian-Portuguese by Mário de AndradeAlmeida, Aline Novais de 02 August 2013 (has links)
Esta dissertação de mestrado tem como objeto a edição genética de A gramatiquinha da fala brasileira obra inacabada e inédita pertencente à série Manuscritos Mário de Andrade, no arquivo do escritor, no patrimônio do Instituto de Estudos Brasileiros da Universidade de São Paulo. Apresentando a obra em fac-símile, esta Edição genética dA gramatiquinha da fala brasileira de Mário de Andrade, inscrita no Programa de Pós-Graduação em Literatura Brasileira da FFLCH-USP, é resultado do projeto temático FAPESP/ IEB e FFLCH-USP, Estudo do processo de criação de Mário de Andrade nos manuscritos de seu arquivo, em sua correspondência, em sua marginália em suas leituras, coordenado, entre 2006-20011, pela Profa. Dra. Telê Ancona Lopez. A partir da análise documental e escritural, à luz da arquivística, da codicologia e da crítica genética, buscou-se compreender a materialidade do dossiê genético e a sistematização, operada por Mário de Andrade, das constâncias da língua portuguesa falada no Brasil. / This dissertation had as object The genetic edition of The little grammar of spoken Brazilian-Portuguese, the unfinished and unpublished manuscripts belonging to the series Mário de Andrade, in the writers file at the patrimony of the Institute for Brazilian Studies, University of São Paulo (IEB/USP). Featuring the work in fac-simile, this edition enrolled the Graduation Program in Brazilian Literature at FFLCH-USP, is a result of the thematic project FAPESP/ IEB/FFLCH-USP Mário de Andrades creative process study: in his manuscripts in his file, his correspondence, in his marginalia in his readings, coordinated between 2006-2011, by professor Telê Ancona Lopez. Based on documentary analysis and scriptural of archivistics, the codicology and genetic criticism, we sought to understand the materiality of genetic dossier and systematization operated by Mário de Andrade, constancies of the Portuguese language spoken in Brazil.
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Manipulating transcription factors in human induced pluripotent cell-derived cells to enhance the production and the maturation of red blood cellsYang, Cheng-Tao January 2017 (has links)
The most widely transfused blood component is red blood cells (RBCs), and voluntary donation is the main resource for RBC transfusion. In the UK, 7,000 units of RBCs are transfused daily but this life-saving cell therapy is completely dependent on donors and there are persistent problems associated with transfusion transmitted infections and in blood group compatibility. Furthermore, the quality, safety and efficiency of donated RBCs gradually decrease with storage time. A number of novel sources of RBCs are being explored including the production of RBCs from adult haematopoietic progenitor cells, erythroid progenitor cell lines and induced pluripotent stem cells (iPSCs). The iPSC source could essentially provide a limitless supply and a route to producing cells that are matched to the recipient. A number of protocols have been described to produce mature RBCs from human pluripotent stem cells but they are relatively inefficient and would be difficult to scale up to the levels required for clinical translation. We tested and evaluated a defined feeder- and serum-free differentiation protocol for deriving erythroid cells from hiPSCs. RBC production was not efficient, the cells that were produced did not enucleate efficiently and they expressed embryonic rather than adult globin. We hypothesised that the production of RBCs from iPSCs could be enhanced by enforced expression of erythroid-specific transcription factors (TFs). Previous studies had demonstrated that Krüppel-like factor 1 (KLF1) plays an important role in RBC development and maturation so we generated iPSC lines expressing a tamoxifen-inducible KLF1-ERT2 fusion protein. Using zinc finger nuclease technology, we targeted the expression cassette to the AAVS1 locus to ensure consistent expression levels and to avoid integration site specific effects and/or silencing. These iKLF1 iPSCs were applied to our defined RBC differentiation protocol and the activity of KLF1 was induced by adding tamoxifen. Activation of KLF1 from day 10 accelerated erythroid differentiation and maturation with an increase in the proportion of erythroblasts, a higher level of expression of erythroid genes associated with maturation and an apparently more robust morphology. However, KLF1 activation had an anti-proliferation effect resulting in significantly less cell generated overall and HPLC analysis demonstrated that KLF1-activated cells expressed higher levels of embryonic globin compared to control iPSCs-derived cells. Many of the effects that were observed when KLF1 was activated from day 10 were not observed when activated from day 18. We therefore concluded that activation of exogenous KLF1 is able to promote erythroid cell production and maturation in progenitors (day 10) but not at the later stage of erythropoiesis (day 18). We hypothesised that KLF1 might require a co-factor to regulate RBC maturation and adult globin expression at the later stage of erythropoiesis. The TF, B-cell lymphoma/leukaemia 11a (BCL11A), plays a key role in the suppression of foetal globin expression, thereby completing globin switching to adult globin. Preliminary data showed that iPSC-derived erythroid cells were able to express adult globin when transduced with a BCL11A-expressing lentiviral-vector. Based on that finding we then generated an iPSC line expressing tamoxifen-inducible BCL11AERT2 and KLF1-ERT2 fusion proteins, applied this iBK iPSC line to our differentiation protocol. Activation of both TFs from day 18 slightly increased the expression of genes associated with RBC maturation and the inclusion of BCL11A appeared to eliminate the anti-proliferation effect of KLF1. Most importantly, activation of both BCL11A and KLF1 from day 18 of the differentiation protocol increased the production of α- globin (foetal / adult globin) indicating that some definitive-like erythroid cells might be generated by activation of both TFs at the later stage of erythroid differentiation. Collectively, these findings demonstrate that enforced expression of erythroid TFs could be a useful strategy to enhance RBC maturation from iPSCs.
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Edição genética d\'A gramatiquinha da fala brasileira de Mário de Andrade / The genetic edition of The little grammar of spoken Brazilian-Portuguese by Mário de AndradeAline Novais de Almeida 02 August 2013 (has links)
Esta dissertação de mestrado tem como objeto a edição genética de A gramatiquinha da fala brasileira obra inacabada e inédita pertencente à série Manuscritos Mário de Andrade, no arquivo do escritor, no patrimônio do Instituto de Estudos Brasileiros da Universidade de São Paulo. Apresentando a obra em fac-símile, esta Edição genética dA gramatiquinha da fala brasileira de Mário de Andrade, inscrita no Programa de Pós-Graduação em Literatura Brasileira da FFLCH-USP, é resultado do projeto temático FAPESP/ IEB e FFLCH-USP, Estudo do processo de criação de Mário de Andrade nos manuscritos de seu arquivo, em sua correspondência, em sua marginália em suas leituras, coordenado, entre 2006-20011, pela Profa. Dra. Telê Ancona Lopez. A partir da análise documental e escritural, à luz da arquivística, da codicologia e da crítica genética, buscou-se compreender a materialidade do dossiê genético e a sistematização, operada por Mário de Andrade, das constâncias da língua portuguesa falada no Brasil. / This dissertation had as object The genetic edition of The little grammar of spoken Brazilian-Portuguese, the unfinished and unpublished manuscripts belonging to the series Mário de Andrade, in the writers file at the patrimony of the Institute for Brazilian Studies, University of São Paulo (IEB/USP). Featuring the work in fac-simile, this edition enrolled the Graduation Program in Brazilian Literature at FFLCH-USP, is a result of the thematic project FAPESP/ IEB/FFLCH-USP Mário de Andrades creative process study: in his manuscripts in his file, his correspondence, in his marginalia in his readings, coordinated between 2006-2011, by professor Telê Ancona Lopez. Based on documentary analysis and scriptural of archivistics, the codicology and genetic criticism, we sought to understand the materiality of genetic dossier and systematization operated by Mário de Andrade, constancies of the Portuguese language spoken in Brazil.
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Approches biographiques de l'"Introduction à l'analyse des lignes courbes algébriques" de Gabriel Cramer / Biographical approaches to Gabriel Cramer's "Introduction à l'analyse des lignes courbes algébriques"Joffredo, Thierry 01 December 2017 (has links)
La parution en 1750 de l'Introduction à l'analyse des lignes courbes algébriques, unique ouvrage publié de Gabriel Cramer, professeur de mathématiques à l'Académie de Genève, est un jalon important dans l'histoire de la géométrie des courbes et de l'algèbre. Il s'est passé près de dix années entre le moment où le Genevois a écrit les premières lignes de son traité des courbes, à l'automne 1740, et sa publication effective : il s'agit de l'œuvre d'une vie.Ce livre a une histoire, à la fois intellectuelle et matérielle, qui s'inscrit dans les contextes scientifiques, professionnels, académiques et sociaux dans lesquels évoluent son auteur puis ses lecteurs. De la genèse d'un texte manuscrit en devenir dont nous suivrons les évolutionsau cours du processus d'écriture et au gré des événements de la vie de son auteur, aux différentes lectures mathématiciennes et historiennes du texte publié qui en sont faites dans les quelque deux siècles qui ont suivi sa publication, je souhaite ici écrire, pour autant que cette expression ait un sens - ce que je m'attacherai à démontrer - une « biographie » de l'Introduction de Gabriel Cramer / The publication in 1750 of the Introduction à l'analyse des lignes courbes algébriques, the only published work by Gabriel Cramer, professor of mathematics at the Geneva Academy, is an important milestone in the history of geometry of curves and algebra. Almost ten years passed between the time when the Genevan wrote the first lines of his treatise on curves in the autumn of 1740 and its actual publication, making it a lifetime achievement.This book has a history, both intellectual and material, which takes place in the scientific, professional, academic and social contexts in which evolve its author and its readers. From the genesis of a handwritten text as a work in progress of which we will follow the evolutions during the process of writing and according to the events of its author's life, to the various mathematicians and historians' readings of the published text which are made in the two centuries following its publication, I would like to write here, insofar as this expression makes sense - which I shall endeavour to demonstrate - a « biography » of Gabriel Cramer's Introduction
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Los péptidos DEVIL: estudio de su papel en el control de la proliferación celular y la morfogénesis de las plantasAlarcia García, Ana 19 February 2024 (has links)
[ES] Los péptidos DEVIL/ROTUNDIFOLIA (DVL/RTFL) constituyen una familia de péptidos de pequeño tamaño codificados por la familia génica DVL/RTFL de 24 miembros en A. thaliana. Estos genes fueron caracterizados por los fenotipos que confiere su sobreexpresión, que provoca cambios pronunciados en la morfología de la planta con hojas de roseta más redondeadas, plantas de menor estatura, peciolos cortos e inflorescencias compactas. Estos fenotipos afectan de un modo fascinante a la morfología de los frutos, que varía según qué miembro de la familia se sobreexprese, demostrando tener un papel en el desarrollo de múltiples órganos de la planta.
Se ha visto que los péptidos DVL/RTFL se localizan en la membrana plasmática y que comparten homología en sus secuencias, con un dominio conservado en el extremo C-terminal, estando además ampliamente conservados en el mundo vegetal. Tanto su localización como dominio funcional conservado resultan ser esenciales para su actividad. Sin embargo y, a pesar de los fenotipos sorprendentes causados por la sobreexpresión de diferentes genes DVL/RTFL, las líneas de pérdida de función no aportan información sobre la función biológica de la familia DVL/RTFL.
En el laboratorio donde se ha realizado este trabajo, se ha avanzado en los últimos años en la caracterización de estos péptidos, su modo de interacción con la membrana celular y la determinación de sus patrones de expresión, así como en la identificación de mutantes de pérdida de función. Para continuar en estas direcciones, en este proyecto se generaron combinaciones de mutantes múltiples estables en diferentes genes DVL/RTFL combinando mutantes de inserción de T-DNA con mutantes generados por CRISPR/Cas9 (dvl3dvl5dvl6dvl1dvl4rtfl9dvl8dvl11rtfl11dvl19). A pesar de que la pérdida de función de múltiples genes DVL/RTFL no mostró fenotipos morfológicos evidentes, análisis transcriptómicos y proteómicos apoyaron la hipótesis de la elevada redundancia génica entre los miembros de esta familia y de que podrían tener un papel en la regulación de procesos como el crecimiento y desarrollo del tubo polínico o el crecimiento distal de la célula.
Experimentos donde analizamos la germinación de polen, el crecimiento de tubo polínico o el desarrollo de pelos radiculares no mostraron que los péptidos DVL/RTFL afectaran de un modo significativo estos procesos , pero sí sugirieron que tienen un rol generalizado aportando estabilidad o robustez al proceso de morfogénesis vía elongación celular.
Adicionalmente se llevaron a cabo estudios de topología de membrana que permitieron confirmar su localización en la membrana plasmática, de tal manera que estos péptidos no se integraban en la membrana, sino que estarían asociados a su interfase. La posibilidad de que la asociación se llevase a cabo a través de otras proteínas hizo que se comprobasen in planta interacciones de los péptidos DVL1 y DVL11 con proteínas candidatas identificadas en un escrutinio de doble híbrido de levadura y relacionadas con procesos de tráfico intra e intercelular, división y elongación celular. Su interacción confirmada con proteínas como SRC2, BSK6 o CDC48 llevó a estudiar la posible relación funcional con éstas y en especial con CDC48 por su implicación en procesos de división, expansión y diferenciación celular, sin obtener resultados concluyentes.
Los escasos resultados obtenidos en Arabidopsis nos condujo a estudiar el papel del único homólogo DVL/RTFL en M. polymorpha. Tras generar y caracterizar líneas de pérdida de función y sobreexpresoras MpDVL, hemos podido confirmar la conservación funcional de los péptidos DVL/RTFL en especies de plantas tan alejadas evolutivamente, así como determinar que no se trata de péptidos esenciales para el desarrollo de la planta pero que sí parecen tener un papel en los procesos de morfogénesis vía elongación celular aportando robustez al sistema.
Este trabajo pone de manifiesto que la necesidad de profundizar en el estudio de los péptidos DVL/RTFL. / [CA] Els pèptids DEVIL/ROTUNDIFOLIA (DVL/DVL) constitueixen una família de pèptids de xicoteta grandària codificats per la família gènica DVL/RTFL de 24 membres en A. thaliana. Aquests gens van ser caracteritzats pels fenotips que confereix la seua sobreexpressió, que provoca canvis pronunciats en la morfologia de la planta amb fulles de roseta més arredonides, plantes de menor alçada, pecíols curts i inflorescències compactes. A més, aquests fenotips afecten d'una manera fascinant a la morfologia dels fruits, que varia segons quin membre de la família es sobreexprese, demostrant tindre un paper en el desenvolupament de múltiples òrgans de la planta.
També s'ha vist que els pèptids DVL/RTFL es localitzen en la membrana plasmàtica i que comparteixen homologia en les seues seqüències, amb un domini conservat en l'extrem C-terminal, estant a més àmpliament conservats en el món vegetal. Tant la seua localització com domini funcional conservat resulten ser essencials per a la seua activitat gènica adequada. No obstant això i, malgrat els fenotips sorprenents observats en la sobreexpressió de diferents gens DVL/RTFL, les línies de pèrdua de funció no aporten informació sobre la funció biològica de la família DVL/RTFL.
En el laboratori on s'ha fet aquest treball, s'ha avançat en els últims anys en la caracterització d'aquests pèptids, la seua manera d'interacció amb la membrana cel·lular i la determinació dels seus patrons d'expressió, així com en la identificació de mutants de pèrdua de funció. Per a continuar en aquestes direccions, en aquest projecte es van generar combinacions de mutants múltiples estables en diferents gens DVL/RTFL combinant mutants d'inserció de T-DNA amb mutants generats per CRISPR/Cas9 (dvl3dvl5dvl6dvl1dvl4rtfl9dvl8dvl11rtfl11dvl19). A pesar que la pèrdua de funció de múltiples gens DVL/RTFL no va mostrar fenotips morfològics evidents, anàlisis transcriptòmics i proteòmics van donar suport a la hipòtesi de l'elevada redundància gènica entre els membres d'aquesta família i que a més tenen un paper en la regulació de processos com són la morfogènesi, el creixement i desenvolupament del tub pol·línic o el creixement distal de la cèl·lula.
Experiments de germinació de pol·len, creixement de tub pol·línic o desenvolupament de pèls radiculars duts a terme van demostrar que els pèptids DVL/RTFL no tenien un paper significatiu en aquests processos, però sí que van suggerir que tenen un rol generalitzat aportant estabilitat o robustesa al procés de morfogènesi via elongació cel·lular.
Addicionalment es van dur a terme estudis de topologia de membrana que van permetre confirmar la seua localització en la membrana plasmàtica, de tal manera que aquests pèptids no s'integraven en la membrana si no que estarien associats a la seua interfase. La possibilitat que aquesta associació es duguera a terme a través d'altres proteïnes va fer que es comprovaren in planta interaccions dels pèptids DVL1 i DVL11 amb proteïnes candidates extretes d'un escrutini de doble híbrid de llevat i relacionades amb processos de trànsit intra i intercel·lular, divisió i elongació cel·lular. La seua interacció confirmada amb proteïnes com SRC2, BSK6 o CDC48 va portar a estudiar la possible relació funcional amb aquests i especialment amb CDC48 per la seua implicació en processos de divisió, expansió i diferenciació cel·lular, sense obtindre resultats concloents.
Els escassos resultats obtinguts en Arabidopsis ens va conduir a estudiar el paper de l'únic homòleg DVL/RTFL en M. polymorpha. Després de generar i caracteritzar línies de pèrdua de funció i de sobreexpressió MpDVL, hem pogut confirmar la conservació funcional dels pèptids DVL/RTFL en espècies de plantes tan allunyades evolutivament, així com determinar que no es tracta de pèptids essencials per al desenvolupament de la planta però que sí que semblen tindre un paper en els processos de morfogènesis via elongació cel·lular aportant robustesa al sistema. / [EN] DEVIL/ROTUNDIFOLIA (DVL/DVL) peptides constitute a family of small peptides encoded by the 24-member DEVIL/ROTUNDIFOLIA (DVL/RTFL) gene family in Arabidopsis thaliana. These genes were characterized by the phenotypes conferred by their overexpression, which causes pronounced changes in plant morphology with round rosette leaves, shorter plants, short petioles, and compact inflorescences. In addition, these phenotypes dramatically affect fruit morphology, which varies depending on which family member is overexpressed, proving to play a role in the development of multiple plant organs.
It has also been shown that DVL/RTFL peptides are located in the plasma membrane, that they share sequence homology, mostly in a conserved C-terminal domain, and that they are also widely conserved among land plants. Both the localization at the membrane and conserved functional domain are essential for proper gene activity. However, despite the surprising overexpression phenotypes observed, the loss-of-function mutants do not provide information on the DVL/RTFL biological function.
In the lab where this work has been carried out, progress has been made in the characterization of these peptides, determining how they interact with the plasma membrane, how they are expressed and accumulated, as well as identifying loss-of-function mutants. To continue in these directions, in this project we have generated combinations of multiple stable DVL/RTFL mutants by combining T-DNA insertion mutants with mutants generated by CRISPR/Cas9 (dvl3 dvl5 dvl6 dvl1 dvl4 rtfl9 dvl8 dvl11 rtfl11 dvl19). Even though the loss of function of multiple DVL/RTFL genes did not show evident morphological phenotypes, transcriptomic and proteomic analyzes supported the hypothesis of a high gene redundancy among the members of this family and suggested that they might have a role in the regulation of processes such as pollen tube growth and development or cell tip growth.
However, pollen germination, pollen tube growth or root hair development experiments did not demostrate that DVL/RTFL peptides had a significant role in these processes, but they suggested that they may have a general role in providing stability or robustness to the morphogenesis process via cell elongation.
Additionally, membrane topology studies were carried out to confirm their location in the plasma membrane, in such a way that these peptides were not integrated but would be associated with the membrane interface. The possibility that this association was carried out through other proteins led to the in planta verification of DVL1 and DVL11 peptide interactions with candidate proteins identified in a previous yeast two-hybrid screening and related to intracellular and intercellular trafficking processes cell division and elongation. The confirmed interaction with proteins such as SRC2, BSK6 or CDC48 led us to study the possible functional relationship with these, and especially with CDC48 due to its involvement in cell division, expansion, and differentiation processes, but unfortunately, we did not obtain conclusive results.
The unconclussive results obtained in Arabidopsis led us to study the role of the unique DVL/RTFL homologue in Marchantia polymorpha. After generating and characterizing MpDVL loss-of-function and overexpression lines, we have been able to confirm the functional conservation of the DVL/RTFL peptides in so evolutionarily distant plant species, as well as to determine that they are not essential for plant development, but they seem to have a role in the morphogenesis processes via cell elongation, providing robustness to the system.
This work highlights the need of furthering the study of DVL/RTFL peptides to discover the mechanism by which they participate in plant development processes and to determine their biological function in depth. / Esta Tesis Doctoral ha sido financiada por la Generalitat Valenciana con una Subvención
para la Contratación de Personal Investigador Predoctoral (ACIF/2018/260), el Ministerio de
Ciencia e Innovación (proyectos BIO2015-64531-R y RTI2018-099239-B-I00), la Generalitat
Valenciana (proyecto PROMETEU/2019/004) y el ExpoSeed H2020-MSCA-RISE-2015-691109 / Alarcia García, A. (2024). Los péptidos DEVIL: estudio de su papel en el control de la proliferación celular y la morfogénesis de las plantas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/202903
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