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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - DivIDe (A multidisciplinary approach to cell division: From human oocyte to synthetic biology)

Teaser

Summary

Cell division is a fundamental process in all organisms and occurs, for instance, during tissue growth and cellular reproduction. The process of cell division is a critical process for each living thing and thus, carefully controlled by a set of genes and proteins. In general, there are two types of cell division: 1) mitosis when cells divide to produce identical daughter cells, and 2) meiosis when cells create eggs and sperm cells with half of the chromosomal content. Mistakes occurred during the cell division process result in changes in the chromosome content or segregation of the daughter cells. These chromosome aberrations can have a huge impact in human health causing cancer, malformations during development, and decreased fertility.

DivIDE is a European training network of international researchers involving five research institutes, one fertility clinic, and two companies that aims to address the mechanisms underlying cell division through an interdisciplinary approach combining molecular biology, biophysics, engineering, mathematical modelling, clinical embryology, and drug discovery. Represented in DivIDE are several aspects of cell division, from the maturation of the human oocyte to the detailed molecular understanding of this finely regulated process of life. To achieve this, our network has two main objectives. First, teach a new generation of molecular engineers to address cell division with interdisciplinary and intersectoral skills. Second, study the functional role of the genetic and post-translational heterogeneity of tubulin, the main building block of microtubules, which are a component of the cytoskeleton and very important in a number of cellular processes such as maintaining the structure and the mechanism of kinetochore assembly.

Work performed

DivIDE recruited 11 young researchers to undertake their research projects in an international, interdisciplinary and intersectoral environment. Each of their research projects addresses cell division from different approaches that are complementary to each other. Both Ivan and Jijumon study tubulin modifications. Ivan is studying how the spatial and temporal polyglutamylation of microtubules by carboxypeptidases (CCPs) participate in spindle assembly and function and found that one of its components impairs the organization and kinetics of microtubule asters. Jijumon managed to purify the central building block of microtubules, tubulin, from mammalian cell lines with a set of precisely defined posttranslational modifications, which allowed him to directly measure how these modifications control the interactions with a panel of microtubule-associated proteins.

Alejandra, Evi, and Pragya address the plasticity and regulation of microtubule function during cell division. Alejandra is studying the mechanisms regulating spindle minus end of microtubules by in vitro reconstitution to perform functional studies. For this, she is purifying all its components. Pragya aims to find an inhibitor of a Tubulin Tyrosine Ligase Like 4 enzyme, which polyglutaminates tubulin a modification involved in neuronal maturation and metastatic progression. Posttranslational modifications of microtubules are also present in human oocytes, and appear to play key roles during meiotic progression. To address their role in human fertility, Evi is studying human oocytes in different maturation states.

Christel, Ana, and Ennio study the topology of protein assemblies within the spindle. Christel studies the mechanism by which dynein complex regulates spindle function and assembly. For this, she has already successfully purified some of its main human components to perform in vitro experiments. In a similar way, Ennio purified Dynactin subcomplexes to study the silencing of Spindle Assembly Checkpoint. Ana studies differences between meiosis and mitosis in the spindle dynamics and chromosome segregation using mutated yeast with meiosis defects. She found which proteins are responsible for spindle elongation during meiosis.

Robert\'s, Manuel\'s, and Pablo\'s research projects focus on the visualization of cell division. Robert aims to obtain the first full 3D reconstructions of mitotic spindles in human cells. To this point, he partially reconstructed spindles in both metaphase and anaphase. Manuel uses mathematical modelling to explain how motor proteins, dynamic filaments, and microtubules assemble to form and elongate the spindle during chromosome segregation. He has been able to mathematically describe that longer spindles elongate faster. Pablo developed a microfluidic device based on the Cherry Temp device that allows thermalizing and perfusing with different buffers a cell sample in the microscope. He has tailored this device for three different experimental needs from Alejandra, Robert and Jijumon.

During the fist two years we organized 5 major training events for our young researchers. The overall results of a survey conducted to the fellows showed the training had a very positive impact on them. As a main outreach activity, DivIDE organized the second edition of the Barcelona Science Slam, which is a public talk contest that takes place in a leisure location where young fellows explain their research projects in maximum 5 minutes to the lay public. During two full days prior to the Science Slam, DivIDE ESRs learned and practiced how to present their research by using simple, and effective storytelling techniques such as analogies and metaphors.

Final results

The advances in understanding how tubulin posttranslational modifications affect cell division will bring a completely novel aspect to the research of cell division. Little was so far known on these modifications, and preliminary results obtained in this network, together with first published reports suggest that their role is to adapt the microtubule network to its specific functions. It appears that these regulatory functions lead to subtle but important changes in microtubule behaviour, and might thus be ideally placed to be key factors leading to late-onset diseases like cancer and neurodegeneration. Finding these mechanisms and at the same time developing potent drugs to control them could be a completely novel approach to treat these diseases. In line, finding small chemical molecules that selectively inhibit the polyglutamylation will be of high interest for human health. These small compounds represent promising starting points for further development of drugs for the treatment of human diseases.

The microfluidic technology developed within DivIDE goes beyond the current state of the art as it improves the understanding of the usage of temperature as a controllable switch/trigger to decipher complex biological phenomena. This advance will most likely raise the interest of the reserach community for thermo-biology in the coming decades. By the end of the project we expect to validate this novel methodology on several models from yeast to human cells to help scientist in their fine understanding of life mechanisms.

DivIDE results show a high potential to be exploited in terms of development of new technology (microfluidics device) and commercialization of therapeutic drugs (patentable small molecules). Importantly, the results obtained from DiVIDE gives the opportunity to show our society that scientific innovation and basic research are complementary as well as having direct impact on their daily life.