RESUMEN
The Innovative Medicines Initiative is a public-private partnership between the European Union and the pharmaceuticals industry that was established in 2008, with an overall budget of 5.3 billion from 2008 until 2024. The objective of the initiative is to boost pharmaceutical innovation in Europe and speed up the development of innovative medicines, vaccines and medical technologies, in particular in areas with high unmet needs. This article discusses the objectives of the initiative, its governance and main results and impact. The initiative has proved to be a unique platform for multi-stakeholder collaborations across Europe. It has contributed to the acceleration of the development process for medicines, from drug discovery to clinical development. The initiative has made important steps towards accessing and using real-world evidence for pharmaceutical research and development, and for healthcare decision-making. Several projects have contributed to a better understanding of the causes of diseases, and some are already delivering results, such as a vaccine against Ebola virus. The initiative has also significantly contributed to building capacity and resources for open use by the broader research and innovation community.
RESUMEN
Organ morphogenesis largely relies on cell division and elongation, which need to be both coordinated between cells and orchestrated with cytoskeleton dynamics. However, components that bridge the biological signals and the effectors that define cell shape remain poorly described. We have addressed this issue through the functional characterisation of QUIRKY (QKY), previously isolated as being involved in the STRUBBELIG (SUB) genetic pathway that controls cell-cell communication and organ morphogenesis in Arabidopsis. QKY encodes a protein containing multiple C2 domains and transmembrane regions, and SUB encodes an atypical LRR-receptor-like kinase. We show that twisting of the gynoecium observed in qky results from the abnormal division pattern and anisotropic growth of clustered cells arranged sporadically along the gynoecium. Moreover, the cortical microtubule (CMT) network of these cells is disorganised. A cross to botero, a katanin mutant in which the normal orientation of CMTs and anisotropic cell expansion are impaired, strongly reduces silique deviation, reinforcing the hypothesis of a role for QKY in CMT-mediated cell growth anisotropy. We also show that QKY is localised at the plasma membrane and functions in a multiprotein complex that includes SUB and PAL OF QUIRKY (POQ), a previously uncharacterised PB1-domain-containing protein that localises both at the plasma membrane and in intracellular compartments. Our data indicate that QKY and its interactors play central roles linking together cell-cell communication and cellular growth.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/embriología , Proteínas Portadoras/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas Tirosina Quinasas Receptoras/metabolismo , Secuencia de Aminoácidos , Anisotropía , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas Portadoras/genética , Comunicación Celular , Membrana Celular/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de la Membrana/genética , Microtúbulos , Datos de Secuencia Molecular , Morfogénesis , Proteínas Tirosina Quinasas Receptoras/genética , Alineación de Secuencia , Transducción de Señal/genéticaRESUMEN
Maternal effects are defined by mutations that affect the next generation when they are maternally inherited. To date, most indepth studies of maternal effects in plants have attributed their origin to genomic imprinting that restricts expression to the maternal allele. The DNA glycosylase DEMETER (DME) removes methylated cytosine residues, causing transcriptional activation of the maternal allele of imprinted genes. In this study, we show that loss-of-function of the major DNA LIGASE I (AtLIG1) in Arabidopsis thaliana causes maternal effects in the endosperm, which is the seed tissue that nurtures embryo development. AtLIG1 expression is not imprinted and has a limited impact on imprinted gene expression. Genetic interaction analyses further indicate that AtLIG1 acts downstream of DME. The removal of methylated cytosine residues by DME involves the creation of DNA single-strand breaks and our results suggest that AtLIG1 repairs these breaks.
Asunto(s)
Proteínas de Arabidopsis/fisiología , Arabidopsis/embriología , Arabidopsis/enzimología , ADN Ligasas/fisiología , Semillas/enzimología , Semillas/crecimiento & desarrollo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , ADN Ligasa (ATP) , ADN Ligasas/genética , Regulación del Desarrollo de la Expresión Génica/genética , Regulación del Desarrollo de la Expresión Génica/fisiología , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Microscopía Confocal , Modelos Genéticos , N-Glicosil Hidrolasas/genética , N-Glicosil Hidrolasas/fisiología , Fenotipo , Plantas Modificadas Genéticamente/embriología , Plantas Modificadas Genéticamente/enzimología , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Polimorfismo Genético/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Semillas/genética , Semillas/metabolismo , Transactivadores/genética , Transactivadores/fisiologíaRESUMEN
In Angiosperms, the male gametes are delivered to the female gametes through the maternal reproductive tissue by the pollen tube. Upon arrival, the pollen tube releases the two sperm cells, permitting double fertilization to take place. Although the critical role of the female gametophyte in pollen tube reception has been demonstrated, the underlying mechanisms remain poorly understood. Here, we describe lorelei, an Arabidopsis thaliana mutant impaired in sperm cell release, reminiscent of the feronia/sirène mutant. Pollen tubes reaching lorelei embryo sacs frequently do not rupture but continue to grow in the embryo sac. Furthermore, lorelei embryo sacs continue to attract additional pollen tubes after arrival of the initial pollen tube. The LORELEI gene is expressed in the synergid cells prior to fertilization and encodes a small plant-specific putative glucosylphosphatidylinositol-anchored protein (GAP). These results provide support for the concept of signaling mechanisms at the synergid cell membrane by which the female gametophyte recognizes the arrival of a compatible pollen tube and promotes sperm release. Although GAPs have previously been shown to play critical roles in initiation of fertilization in mammals, flowering plants appear to have independently evolved reproductive mechanisms that use the unique features of these proteins within a similar biological context.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Células Germinativas/crecimiento & desarrollo , Tubo Polínico/crecimiento & desarrollo , Secuencia de Aminoácidos , Arabidopsis/embriología , Proteínas de Arabidopsis/genética , Mapeo Cromosómico , ADN de Plantas/genética , Fertilización/genética , Glicosilfosfatidilinositoles/metabolismo , Datos de Secuencia Molecular , Mutación , Tubo Polínico/genéticaRESUMEN
Angiosperms sexual reproduction involves interactions between the two female gametes in the embryo sac and the two male gametes released by the pollen tube. The two synergids of the embryo sac express the FERONIA/SIRENE receptor-like kinase, which controls the discharge of the two sperm cells from the pollen tube. FER/SRN may respond to a ligand from the pollen tube. Alternatively, the interaction between FER/SRN and a ligand from the embryo sac may lead to a state of competence of the synergids allowing pollen tube discharge. Here, we report the new mutant scylla (syl) impaired in the control of pollen tube discharge. This mutant also produces autonomous endosperm development in absence of fertilization-a trait associated with the FERTILIZATION INDEPENDENT SEED (FIS) mutant class. This led us to identify autonomous endosperm in srn mutants and to demonstrate synergistic interactions between srn and the fis mutants. In addition, the fis mutants display defects in pollen tube discharge as in srn and syl mutants, confirming the interaction between the two pathways. Our findings suggest that pollen tube discharge is controlled by an interaction between the synergids expressing SRN/FER and the central cell expressing FIS genes.
Asunto(s)
Proteínas de Arabidopsis/metabolismo , Arabidopsis/fisiología , Fertilización/fisiología , Óvulo Vegetal/citología , Óvulo Vegetal/enzimología , Fosfotransferasas/metabolismo , Polen/citología , Semillas/fisiología , Arabidopsis/citología , Arabidopsis/enzimología , Endospermo/citología , Mutación/genética , Fenotipo , Tubo Polínico/citología , Tubo Polínico/enzimología , Tubo Polínico/fisiología , Transducción de SeñalRESUMEN
Research infrastructures are essential for top-level academic and industrial research activities. Throughout the successive framework programmes (FPs) of the EU, actions have been gradually developed to support researchers in accessing top-level European research infrastructures located outside their own country and also to better coordinate and integrate these infrastructures Europe-wide, enabling better research services. At the same time, research infrastructures pave the way for the development of scientific and technological advances. Under the sixth Framework Programme (FP6; 2002-2006), for example, nanobiotechnologies have benefited from these European actions through three approaches: the support of multi-disciplinary pan-European infrastructures; the support of pan-European infrastructures dedicated to biology but with usage in multiple domains of biology; and the funding of integrated centers for nanobiotechnologies. The seventh Framework Programme (FP7; 2007-2013) will reinforce these actions toward research infrastructures, with particular attention to the emergence of new ones as well as to the provision of important strategic research services in fields such as nanobiotechnologies.
Asunto(s)
Biotecnología/organización & administración , Unión Europea/organización & administración , Programas de Gobierno/organización & administración , Nanotecnología/organización & administración , Política Pública , Investigación/organización & administraciónRESUMEN
In contrast to animals, the plant male germline is established after meiosis in distinctive haploid structures, termed pollen grains. The germline arises by a distinct asymmetric division of the meiotic products . The fates of the resulting vegetative and generative cells are distinct. In contrast to the larger vegetative cell, arrested in the G1 phase of the cell cycle, the smaller generative cell divides once to produce the two male gametes or sperm cells. Sperm cells are delivered to the female gametes by the pollen tube, which develops from the vegetative cell. In spite of recent efforts to understand pollen development , the molecular pathway controlling sperm-cell ontogenesis is unknown. Here, we present the isolation of DUO1, a novel R2R3 MYB gene of Arabidopsis, as the first gene shown to control male gamete formation in plants. DUO1 is specifically expressed in the male germline, and DUO1 protein accumulates in sperm-cell nuclei. Mutations in DUO1 produce a single larger diploid sperm cell unable to perform fertilization. DUO1 appears to be evolutionarily conserved in several plant species and defines a new subfamily of pollen-specific MYB genes.
Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/embriología , Arabidopsis/genética , Expresión Génica , Meiosis/fisiología , Fenotipo , Polen/embriología , Factores de Transcripción/genética , Secuencia de Aminoácidos , Proteínas de Arabidopsis/fisiología , Cruzamientos Genéticos , Cartilla de ADN , Datos de Secuencia Molecular , Filogenia , Proteínas Proto-Oncogénicas c-myb/genética , Proteínas Proto-Oncogénicas c-myb/fisiología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Alineación de Secuencia , Análisis de Secuencia de ADN , Factores de Transcripción/fisiologíaRESUMEN
In higher plants, double fertilisation initiates seed development. One sperm cell fuses with the egg cell and gives rise to the embryo, the second sperm cell fuses with the central cell and gives rise to the endosperm. The endosperm develops as a syncytium with the gradual organisation of domains along an anteroposterior axis defined by the position of the embryo at the anterior pole and by the attachment to the placenta at the posterior pole. We report that ontogenesis of the posterior pole in Arabidopsis thaliana involves oriented migration of nuclei in the syncytium. We show that this migration is impaired in mutants of the three founding members of the FERTILIZATION INDEPENDENT SEED (FIS) class, MEDEA (MEA), FIS2 and FERTILIZATION INDEPENDENT ENDOSPERM (FIE). A screen based on a green fluorescent protein (GFP) reporter line allowed us to identify two new loci in the FIS pathway, medicis and borgia. We have cloned the MEDICIS gene and show that it encodes the Arabidopsis homologue of the yeast WD40 domain protein MULTICOPY SUPRESSOR OF IRA (MSI1). The mutations at the new fis loci cause the same cellular defects in endosperm development as other fis mutations, including parthenogenetic development, absence of cellularisation, ectopic development of posterior structures and overexpression of the GFP marker.
Asunto(s)
Proteínas de Arabidopsis/genética , Arabidopsis/fisiología , Proteínas Represoras/genética , Semillas/fisiología , Factores de Transcripción/genética , Arabidopsis/genética , Arabidopsis/crecimiento & desarrollo , Proteínas de Arabidopsis/análisis , Polaridad Celular/genética , Mapeo Cromosómico , Cruzamientos Genéticos , Fertilización/genética , Rayos gamma , Proteínas Represoras/análisis , Semillas/efectos de la radiación , Factores de Transcripción/análisisRESUMEN
In flowering plants, two male gametes from a single pollen grain fuse with two female gametes, the egg and central cells, to form the embryo and endosperm, respectively. The question then arises whether the two male gametes fuse randomly with the egg and central cells. We investigated this question using two nearly isogenic maize lines with supernumerary B chromosomes (TB10L18) or without (r-tester). B chromosomes regularly undergo non-disjunction at the second pollen mitosis, producing one sperm cell with zero B chromosomes and one with two. We first confirmed earlier studies showing an excess of transmission of the B chromosomes to the embryo rather than to the endosperm. We then tested the possibility of a directed fertilization. For TB10L18 pollen, we could demonstrate the existence of a size dimorphism between the two sperm cells, correlated to the content in B chromosomes, as detected by fluorescence in situ hybridization (FISH). However, no directed fusion of B chromosome containing sperm to egg cells could be detected when using in vitro fertilization. The absence of directed fusion in vitro could also be demonstrated for control lines. We conclude that both male gametes have the capacity to fuse with the egg cell in maize, although sexual reproduction results in a preferential transmission of supernumerary B chromosomes.
Asunto(s)
Fertilización/fisiología , Óvulo/fisiología , Polen/fisiología , Zea mays/fisiología , Cromosomas de las Plantas/genética , No Disyunción Genética , Polen/citología , Polen/genética , Interacciones Espermatozoide-Óvulo , Zea mays/citología , Zea mays/genéticaRESUMEN
Fertilization in both animals and plants relies on the correct targeting of the male gametes to the female gametes. In flowering plants, the pollen tube carries two male gametes through the maternal reproductive tissues to the embryo sac, which contains two female gametes. The pollen tube then releases its two male gametes into a specialized receptor cell of the embryo sac, the synergid cell. The mechanisms controlling this critical step of gamete delivery are unknown. Here, data based on the new sirène (srn) mutant of Arabidopsis thaliana provide the first evidence for female control over male gamete delivery. Live imaging of fertilization shows that wild-type pollen tubes do not stop their growth and do not deliver their contents in srn embryo sacs.
Asunto(s)
Arabidopsis/fisiología , Fertilización/fisiología , Arabidopsis/genética , Fertilización/genética , Flores/genética , Flores/fisiologíaRESUMEN
We describe some previously uncharacterised stages of fertilization in Arabidopsis thaliana and provide for the first time a precise time course of the fertilization process. We hand-pollinated wild type pistils with wild type pollen (Columbia ecotype), fixed them at various times after pollination, and analysed 600 embryo sacs using Confocal Laser Scanning Microscopy. Degeneration of one of the synergid cells starts at 5 Hours After Pollination (HAP). Polarity of the egg changes rapidly after this synergid degeneration. Karyogamy is then detected by the presence of two nucleoli of different diameters in both the egg and central cell nuclei, 7-8 HAP. Within the next hour, first nuclear division takes place in the fertilized central cell and two nucleoli can then be seen transiently in each nucleus produced. In a second set of experiments, we hand-pollinated wild type pistils with pollen from a transgenic promLAT52::EGFP line that expresses EGFP in its pollen vegetative cell. Release of the pollen tube contents into the synergid cell could be detected in living material. We show that the timing of synergid degeneration and pollen tube release correlate well, suggesting that either the synergid cell degenerates at the time of pollen tube discharge or very shortly before it. These observations and protocols constitute an important basis for the further phenotypic analysis of mutants affected in fertilization.