Germ Band Extension in Drosophila String Mutants

In Drosophila germ band extension, cell intercalation is achieved by contraction of vertical interfaces and elongation of horizontal interfaces between two neighboring cells. The symmetry breaking behavior in the system (i.e. the preferential contraction of vertical and preferential elongation of horizontal interfaces) results from a system of planar polarity - meaning a spatially anisotropic distribution of certain molecules - which consists of Myosin at vertical and Bazooka at horizontal interfaces. The process of germ band extension usually occurs over approximately 30 minutes, which is followed by mitotic cell division. A mutation in cell-cycle regulating String protein allows to potentially extend the intercalation window by hindering mitosis. Using movies of the String mutant embryos and computational analysis, my project aimed to answer whether cell divisions are critical for termination of the germ band extension process, specifically by measuring whether the planar polarity of Myosin/Bazooka recruitment and contraction/elongation behavior is prolonged in the String mutants. The results contribute to understanding the processes that govern the germ band extension in Drosophila development and provide insights for further investigation of these stages. Understanding the developmental processes in Drosophila allows us to then use it as a better animal model for research in other areas of biological sciences.