LAP2alpha and BAF transiently localize to telomeres and specific regions on chromatin during nuclear assembly.
Lamina-associated polypeptide (LAP) 2alpha is a LEM (lamina-associated polypeptide emerin MAN1) family protein associated with nucleoplasmic A-type lamins and chromatin. Using live cell imaging and fluorescence microscopy we demonstrate that LAP2alpha was mostly cytoplasmic in metaphase and associated with telomeres in anaphase. Telomeric LAP2alpha clusters grew in size, formed 'core' structures on chromatin adjacent to the spindle in telophase, and translocated to the nucleoplasm in G1 phase. A subfraction of lamin C and emerin followed LAP2alpha to the core region early on, whereas LAP2beta, lamin B receptor and lamin B initially bound to more peripheral regions of chromatin, before they spread to core structures with different kinetics. Furthermore, the DNA-crosslinking protein barrier-to-autointegration factor (BAF) bound to LAP2alpha in vitro and in mitotic extracts, and subfractions of BAF relocalized to core structures with LAP2alpha. We propose that LAP2alpha and a subfraction of BAF form defined complexes in chromatin core regions and may be involved in chromatin reorganization during early stages of nuclear assembly.
Dechat
Thomas
T
Max F. Perutz Laboratories, University Departments at the Vienna Biocenter, Department of Medical Biochemistry, Medical University of Vienna, 1030 Vienna, Austria.
Gajewski
Andreas
A
Korbei
Barbara
B
Gerlich
Daniel
D
Daigle
Nathalie
N
Haraguchi
Tokuko
T
Furukawa
Kazuhiro
K
Ellenberg
Jan
J
Foisner
Roland
R
D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002843:Chromatin / Q000378:metabolism; D002875:Chromosomes / Q000000981:diagnostic imaging / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015151:Immunoblotting; D047468:Immunoprecipitation; D007668:Kidney / Q000166:cytology; D034882:Lamins / Q000378:metabolism; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000648:ultrastructure; D008938:Mitosis; D008954:Models, Biological; D009687:Nuclear Proteins / Q000096:biosynthesis* / Q000378:metabolism; D011485:Protein Binding; D051381:Rats; D016615:Telomere / Q000378:metabolism / Q000648:ultrastructure*; D014463:Ultrasonography
C501959:BANF1 protein, human; D001426:Bacterial Proteins; C501961:Banf1 protein, rat; D002843:Chromatin; D004268:DNA-Binding Proteins; D006657:Histones; D034882:Lamins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; C093413:lamina-associated polypeptide 2; C054562:yellow fluorescent protein, Bacteria; D004247:DNA