Investigating the Role of Septate Junction Proteins during Border Cell Migration
Authors: Giovanni Sabatino 1; Haifa Alhadyian 2; Robert Ward 1
Affiliations: 1) Case Western Reserve University; 2) University of Kansas
Keywords: p. cell migration; aa. tissue growth
Border cell migration during oogenesis is an excellent system to study aspects of cell migration including polarity, leading edge dynamics, and migratory adhesion. We previously found that knocking down any of several septate junction genes in the border cells resulted in poorly penetrant defects including delayed border cell migration and fragmentation of the border cell cluster. The low penetrance is likely due to the long lifespan of septate junction proteins, coupled with the short time frame during which border cell migration occurs. The septate junction is an analogous structure to the vertebrate tight junction, allowing for occlusion in the epithelium, but septate junction proteins have also been shown to be required for morphogenetic events independent of their role in forming an occluding junction. To gain a better understanding of the function of septate junction proteins in border cell migration we are using confocal microscopy of fixed and live egg chambers expressing RNAi against coracle and Macroglobulin-complement related in heterozygous mutant backgrounds. We are particularly interested in directionality of migration, migratory cell cohesion, and the dynamics of the cytoskeleton at the leading edge. Live microscopy should allow us to observe the actin-myosin leading edge dynamics in real time, as well as better understand if loss of axial direction causes defective border cell migration. Septate junction proteins play diverse roles in embryonic development, and so, by characterizing their effects on border cell migration, we hope to discover new information about the mechanisms of embryogenesis and collective cell migration.