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BP: Fachverband Biologische Physik
BP 13: Cytoskeleton
BP 13.3: Vortrag
Mittwoch, 7. September 2022, 10:15–10:30, H15
Image analysis and modelling of nascent sarcomeres during myofibrillogenesis — •Ian D. Estabrook1, Francine Kolley1, Clément Rodier2, Frank Schnorrer2, and Benjamin M. Friedrich1,3 — 1cfaed, TU Dresden — 2IBDM, Aix Marseille University — 3Physics of Life, TU Dresden.
All animals possess striated muscle, which enable their voluntary movements. Inside muscle cells, actin and myosin molecular motors together with actin crosslinkers and the giant protein titin are arranged in long chains of sarcomeres in so-called myofibrils of almost crystalline regularity. Despite their physiological importance, it remains poorly understood how myofibrils spontaneously self-assemble during myofibrillogenesis. To investigate this molecular pattern formation process, our group combines image analysis and mathematical modelling, in close collaboration with the experimental Schnorrer lab.
We automatically analysed thousands of sarcomeres using a custom Matlab-based feature detection algorithm to analyse three-dimensional multi-channel fluorescence images of the Drosophila flight muscle. This allows us to compute averaged spatial intensity profiles of key proteins at different stages of myofibrillogenesis, providing a pseudo-time course of sarcomere assembly. Additionally, we observe rare abnormal sarcomeres, which reveals a a new mechanism by which a ’mother sarcomere’ splits into two ’daughter sarcomeres’. This data drives mathematical modelling: minimal models demonstrate that non-local interactions between spatially extended myosin and titin molecules, as well as actin crosslinkers are sufficient to replicate sarcomeric pattern formation.