Lipid Mapping of Cell Mitosis by Non-covalent Migratory Fluorescence Labelling

Abstract

The concept of non-covalent migratory fluorescence labelling is introduced to spatially and temporally map intracellular lipids throughout a cell division cycle. This hands-off approach utilizes a small molecule BF 2 -azadipyrromethene fluorophore, NM-ER, to first label the nuclear membrane and endoplasmic reticulum of cells at interphase but which can migrate with the lipid components of these structures throughout mitosis as they disassemble, redistribute and reassemble prior to daughter cell separation. Through this unique approach to image capture, key prometaphase events such as lipid intrusion into the nucleus and nuclear membrane disassembly are observable, as are the stages of nuclear membrane reassembly in telophase and lipid distribution during cytokinesis. When used alone NM-ER can distinguish each phase of cell mitosis from lipid staining patterns, is compatible with STED super resolution imaging, and with an emission max of 648 nm makes it useable with other common GFP and nuclear DNA stains. The non-covalent NM-ER label remains associated with the originating lipid components as they undergo architectural reorganizations and changes in subcellular localization associated with mitosis. As lipid-based cell structures are influenced by numerous biological processes and mechanical forces, our approach to fluorescence imaging could offer novel perspectives into their different roles.