MESODERM EVOLUTION · The development and evolution of the mesoderm in basal bilaterian acoel worms
7РП — „Хора“ (Действия „Мария Кюри“)
- Период
- 2010-11-01 → 2014-10-31
- Финансиране от ЕС
- 100 000 €
- Участници
- 1
- Схема
- MC-IRG
Линиите свързват координатора с партньорите.
Накратко на български
Развитието на мезодермата (средния зародишен слой) се проследява при червеи от вида Isodiametra pulchra чрез микроскопия и генетичен анализ. Това помага да се разбере как се формират различните видове клетки и как еволюират тъканите при базовите двустранно-симетрични организми.
Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.
Резултати накратко
The development and evolution of the mesoderm in basal bilaterian acoel worms
We have investigated the mesoderm development in the representative acoel species Isodiametra pulchra using fate map analysis and gene expression studies. The primary objectives of the proposal were: Objective 1: Description of endoderm and mesoderm formation and identification of candidate genes in an acoel species. We have used 4D-microscopic and fate mapping approaches to characterise the mesoderm development in the acoel Isodiametra pulchra. Our results that the mesoderm is formed from two blastomeres at the vegetal pole of the 16-cell stage embryo. This is consistent with previous descriptions but we have gained a more detailed fatemap using confocal imaging of living fluorescently labeled worms. We found that the acoel stem cells (neoblasts) - are in low numbers in the juvenile worm and will grow to larger numbers during development. We have studies the expression of mesodermal transcription factors in the acoel and found that only a small number of mesodermal cell types are present. The so-called ‘parenchyme’ must be secondarily derived from mesoderm in the lineage to the Acoel a (Chiodin et al 2013). This work is a starting point and also led to the establishment of several methods in the acoel species I. pulchra: I. microinjection of cell tracing dyes into individual blastomeres of the 16-cell stage, II. Live imaging microscopy using a 3D-timelapse microscope II. double fluorescent in situ hybridization in combination with EdU as stem cell marker. Further investigations will be necessary to unravel the differentiation of mesodermal cell types. Objective 2: Quantification and timing of expression of candidate genes We have successfully established a method for stage specific next generation sequencing to determine the rate of expression during different developmental stages. This replaced the method originally proposed (microarrays). In combination with the sequenced genome of Isodiametra pulchra, we are able to determine the amount of expression during a dozen developmental stages. Currently we are improving the method to single-cell sequencing of blastomeres and tissues to determine the temporary and quality changes during the development. The tissue specific transcriptomes will also help to determine lineage specific genes that are responsible for mesoderm formation. Objective 3: Approach to identify the specific function of the genes and the reconstruction of the gene regulatory network The most ambitious objective was only reached partially. We have established RNA inference methods by injecting double stranded RNA into individual blastomeres. We were successfully able to knock down the function of some genes. We also decided to establish ballistic transformations in Isodiametra pulchra. We have furthermore contributed to sequencing the genome and transcriptome of the acoel which is currently being analyzed in comparative manner with that of other acoel, nemertodermatid and Xenoturbella species.
Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз
Цел на проекта
Understanding the evolution of the diversity of animal forms is one of the major tasks in biology. The use of molecular biology led to a better understanding of how evolutionary changes in the development can result in changes in the body plan. Modifications of the wiring between genes caused the adoption and co-option of gene regulatory networks that shape the morphology of the adult during the development. To get a better picture of how these changes led to evolutionary novelties one has to investigate animals that are representatives of key-nodes in the animal tree of life. A fundamental innovation of complex animals is the third germ layer – the mesoderm, that is characteristic for all bilateral symmetric animals that include flies, worms and humans. The mesoderm gives rise to important organ systems such as skeletal elements, musculature, heart and kidneys. Recent insights gained from studies of the development of cnidarians – the most closely related group of the bilaterians – suggest, that the mesoderm evolved from the internal germ layer the endoderm. Comparative studies between animals can reveal how the gene regulatory network that specifies the endoderm of cnidarians has been changed so that it gives rise to a novel germ layer, the mesoderm. The ideal organisms to investigate for answering this question are the simple acoel worms, which form the earliest evolutionary branch of all bilaterian animals. The proposed research project has the aim to investigate the gene regulatory network that specifies the endoderm and mesoderm of the acoel species Convolutriloba longifissura using modern molecular tools. By describing the detailed temporal and spatial expression of key regulatory genes and a following functional analysis important information will be gained that delivers the basis for a comparisons to identify the changes in the gene regulatory network that promoted the evolution of three germ layers and thus the evolution of more complex animals.
Оригинален текст от CORDIS (на английски).
Участници
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Връзки
Данни: CORDIS, © Европейски съюз