The research group is a multidisciplinary team interested in the physical aspects of intracellular organization.
As a model system, they study the earliest stage of Drosophila development, from oogenesis to the mature egg to fertilization and blastoderm cleavages. On one hand, they focus on pronuclear fusion in the fertilized egg and how the syncytial embryo defines the inter-nuclear distance between rapid mitotic divisions. On the other hand, researchers study the physical and biochemical rules determining oocyte polarity.
They use a variety of approaches from chemistry, molecular biology, genetic engineering, micromechanics and optical microscopy.
Their core experimental platform is a cytoplasmic explant assay using single oocytes, mature eggs or early embryos.
In Drosophila embryos nuclei undergo rapid successive divisions without cytokinesis and, therefore, a vast number of nuclei share the same intracellular space in a syncytium. They need to be evenly distributed throughout a large cytoplasmic volume and brought to the cell cortex to form the blastoderm. The regular arrangement of the nuclei is vital to later embryo development, and defects that perturb this distribution are lethal. How the regular nuclear distribution during early divisions is achieved and maintained is an interesting yet unresolved question. In each division cycle a single nucleus gives rise to two sister nuclei that are separated by the mitotic spindle. In this project we investigate how the non-sister nuclei remain separated and do not collide with each other. We particularly focus on the microtubule-based molecular interactions that regulate the distance between neighboring non-sister nuclei.
The intracellular positioning of the nucleus has gained substantial interest among biologists due its relevance in cell cycle, differentiation, migration, and polarity. Abnormal positioning has been related to cell and tissue function deficiency and severe defects in embryogenesis. Membrane linkers and cytoskeletal and molecular motor dynamics are essential factors for nuclear movement. However, understanding the coordination and the quantification of force generating elements for nuclear positioning are current challenges. In this project, we investigate time-resolved nuclear distribution starting at the earliest stage of Drosophila embryo development to understand causality and regulation of nuclear positioning. We infer on how predefined external factors (e.g. neighbor nuclei, cytoplasmic volume, geometry) influence the dynamics of the cytoskeletal machinery surrounding a nucleus, with focus on microtubules, actin, associated molecular motors and linking proteins.
Fertilization is a vital process as it lies at the heart of animal reproduction. Because fertilization happens deep inside the egg, which is carried inside a living organism and filled with diffractive yolk, time-lapse light microscopy has been challenging. Most of the existing knowledge on insect fertilization was obtained from the analysis of fixed and immunostained eggs. Thus, we lack important temporal and dynamic information of molecular and cellular processes such as chromosome and cytoskeletal dynamics. The main goal of this project is to develop a reconstitution assay of Drosophila melanogaster fertilization enabling live microscopy. Our assay will open new avenues to study chromosomal dynamics during fertilization enabling more detailed insight, for example, into bacteria transmission and cytoplasmic incompatibility (CI).