Germ Band Extension in Drosophila String Mutants
Date of Award
Spring 6-8-2023
Document Type
Undergraduate Thesis
Degree Name
Bachelor of Science in Molecular Biology
Organizational Unit
College of Natural Science and Mathematics, Biological Sciences
First Advisor
Dinah Loerke
Second Advisor
James Todd Blankenship
Keywords
Germ band extension, Drosophila, Developmental biology, Fast phase, String, T1 transitions
Abstract
In Drosophila germ band extension, cell intercalation is achieved by contraction of vertical interfaces (between anterior-posterior neighboring cells), and elongation of horizontal interfaces (between two dorsal-ventral neighboring cells). The symmetry-breaking behavior results from a system of planar polarity, which is created by anisotropic distribution of certain proteins at cell-cell interfaces – Myosin II at vertical and Bazooka at horizontal interfaces. The cell-cell interfaces systematically rotate towards vertical orientations to induce Myosin II recruitment to the membrane as a function of the angle of the interface. The fast phase of germ band extension usually occurs over approximately 30 minutes, which is followed by mitotic cell divisions. This results in displacement of the observed cells of the germ band from the imaging field by the dividing cells. A mutation in cell-cycle regulating String protein allows us to potentially extend the intercalation window by hindering the mitosis. Using the String mutant, this study aimed to answer whether cell divisions are critical for termination of the fast phase of the germ band extension process, specifically by measuring whether the planar polarity of Myosin II recruitment and contraction/elongation behavior is prolonged in the String mutant. The results support that the anisotropic distribution of Myosin II, and the contraction/elongation behavior are partially preserved in the String mutant. This suggests that the mitotic cell divisions play a role in the termination of the fast phase of the germ band extension, but there are likely other mechanisms that are required for the transition between the germ band elongation phases.
Publication Statement
Copyright is held by the author. Permanently suppressed.
Recommended Citation
Cudova, Barbora, "Germ Band Extension in Drosophila String Mutants" (2023). Undergraduate Theses, Capstones, and Recitals. 14.
https://digitalcommons.du.edu/undergraduate_theses/14