Abstract
Amplified centrosome number causes genomic instability, most severely through division into more than two aneuploid daughter cells (multipolar mitosis). Several mechanisms that suppress multipolar division have been uncovered, yet mechanisms that favor viable multipolar division are poorly understood. To uncover factors that promote viability in cells with frequent centrosome amplification and multipolar division, we conducted an unbiased Drosophila genetic screen. In 642 mutagenized lines, we exploited the ability of intestinal papillar cells to form and function despite multipolar divisions. Our top hit is an unnamed gene, CG3168 . We name this gene synaptic vesicle glycoprotein 2 , reflecting homology to human Synaptic Vesicle Glycoprotein 2 (SV2) proteins. GFP-tagged SV2 localizes to the plasma membrane. In cells with amplified centrosomes, SV2 positions membrane-adjacent centrosomes, which prevents severe errors in chromosome alignment and segregation. Our results uncover membrane-based multipolar division regulation and reveal a novel vulnerability in cells with common cancer properties.