Three Types of Nuclear Envelope Assemblies Associated with Micronuclei

Abstract

While micronuclei (MN) store extranuclear DNA and cause genome instability, the effects of nuclear envelope (NE) assembly defects associated with MN on genome instability remain largely unknown. Here, we investigated the NE protein distribution in MN using HeLa human cervical cancer cells. Under the standard condition and two pharmacological culture conditions, we found that three types of NE protein assemblies were associated with MN: 1) intact NE assembly, in which both core and non-core NE proteins were evenly present; 2) type I assembly, in which only core NE proteins were detectable; and 3) type II assembly in which a region deficient for both core and non-core NE proteins existed and a pattern recognition receptor, cyclic guanosine monophos-phate-adenosine monophosphate synthase, was frequently detected. Our findings provide experimental settings and a method of grouping MN-associated NE defects, which may be helpful for researchers who are interested in regulation of genome and nuclear organization relevant to cancer development.