Aurora B–mediated localized delays in nuclear envelope formation facilitate inclusion of late-segregating chromosome fragments

Abstract

To determine how chromosome segregation is coordinated with nuclear envelope formation (NEF), we examined the dynamics of NEF in the presence of lagging acentric chromosomes in Drosophila neuroblasts. Acentric chromosomes often exhibit delayed but ultimately successful segregation and incorporation into daughter nuclei. However, it is unknown whether these late-segregating acentric fragments influence NEF to ensure their inclusion in daughter nuclei. Through live analysis, we show that acentric chromosomes induce highly localized delays in the reassembly of the nuclear envelope. These delays result in a gap in the nuclear envelope that facilitates the inclusion of lagging acentrics into telophase daughter nuclei. Localized delays of nuclear envelope reassembly require Aurora B kinase activity. In cells with reduced Aurora B activity, there is a decrease in the frequency of local nuclear envelope reassembly delays, resulting in an increase in the frequency of acentric-bearing, lamin-coated micronuclei. These studies reveal a novel role of Aurora B in maintaining genomic integrity by promoting the formation of a passageway in the nuclear envelope through which late-segregating acentric chromosomes enter the telophase daughter nucleus.