File name: LaminB_Receptor.mov
Authors: Tokuko Haraguchi and Yasushi Hiroaka

Playback rate: 4 frames/second

Legend of the movie: This movie shows the dynamic behavior of human lamin B receptor-GFP (green) and chromosomes (red) in living HeLa cells. This shows the whole process of the disassembly and assembly of the nuclear envelope during mitosis: LBR-GFP was localized in the nuclear envelope in interphase cells. Upon the nuclear envelope breakdown at prometaphase, LBR-GFP was dispersed into the cytoplasm. Then, LBR-GFP reappeared around chromosomes in telophase, showing that the nuclear envelope was reorganized.

Background: Lamin B receptor (LBR) is an integral membrane protein possessing the ability to bind nuclear lamin B and chromatin and is known to localize in the inner membrane of nuclear envelope. This protein is a good marker to observe the dynamic process of disassembly and assembly of the nuclear envelope during mitosis. This movie suggests that LBR may be involved in the initial process to reform the nuclear envelope around chromosomes during telophase.

Reference:
1. Ye Q. and Worman H.J., 1994, J. Biol. Chem. vol. 269, 11306-11311.
2.Gant T.M. and Wilson K.L., 1997, Annu. Rev. Cell Dev. Biol., vol. 13,669-695.

Methods: Transfection; microinjection of plasmid DNA into the nucleus. Microscopy; The DeltaVision (Applied Precision Inc. Seattle, USA) fluorescence microscope system. Microscope equipments; an Olympus inverted microscope IX70, UApo 40x ( NA=1.35), a Peltier-cooled CCD camera (photometrics Ltd., Tucson, USA), a 2 m optical fiber for illumination, a UNIX workstation Indigo2 (Silicon Graphics, USA), a temperature controlled room and a microinjector (Eppendorf model 5171 and 5242). The experiment was carried out at 37 C and the time-lapse image data were collected every 5 min at an exposure of 0.5 sec for LBR-GFP and 0.5 sec for Hoechst33342 for more than 5 hours.