Asymmetric partitioning of transfected DNA during mammalian cell division.
Foreign DNA molecules and chromosomal fragments are generally eliminated from proliferating cells, but we know little about how mammalian cells prevent their propagation. Here, we show that dividing human and canine cells partition transfected plasmid DNA asymmetrically, preferentially into the daughter cell harboring the young centrosome. Independently of how they entered the cell, most plasmids clustered in the cytoplasm. Unlike polystyrene beads of similar size, these clusters remained relatively immobile and physically associated to endoplasmic reticulum-derived membranes, as revealed by live cell and electron microscopy imaging. At entry of mitosis, most clusters localized near the centrosomes. As the two centrosomes split to assemble the bipolar spindle, predominantly the old centrosome migrated away, biasing the partition of the plasmid cluster toward the young centrosome. Down-regulation of the centrosomal proteins Ninein and adenomatous polyposis coli abolished this bias. Thus, we suggest that DNA clustering, cluster immobilization through association to the endoplasmic reticulum membrane, initial proximity between the cluster and centrosomes, and subsequent differential behavior of the two centrosomes together bias the partition of plasmid DNA during mitosis. This process leads to their progressive elimination from the proliferating population and might apply to any kind of foreign DNA molecule in mammalian cells. Furthermore, the functional difference of the centrosomes might also promote the asymmetric partitioning of other cellular components in other mammalian and possibly stem cells.
Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), CH-8093 Zurich, Switzerland, Molecular Life Science PhD Program, Life Science Zurich Graduate School, CH-8057 Zurich, Switzerland.
Xuan
X
Wang
Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), CH-8093 Zurich, Switzerland, Molecular Life Science PhD Program, Life Science Zurich Graduate School, CH-8057 Zurich, Switzerland.
Nhung
N
Le
Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), CH-8093 Zurich, Switzerland, Molecular Life Science PhD Program, Life Science Zurich Graduate School, CH-8057 Zurich, Switzerland.
Annina
A
Denoth-Lippuner
Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), CH-8093 Zurich, Switzerland.
Yves
Y
Barral
Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zurich (ETH Zurich), CH-8093 Zurich, Switzerland, ruth.kroschewski@bc.biol.ethz.ch.
Ruth
R
Kroschewski
D000818:Animals; D002455:Cell Division; D018385:Centrosome / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics; D004247:DNA / Q000378:metabolism*; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D061985:Madin Darby Canine Kidney Cells; D008938:Mitosis; D009687:Nuclear Proteins / Q000235:genetics; D010957:Plasmids; D014162:Transfection
D003598:Cytoskeletal Proteins; C512806:NIN protein, human; D009687:Nuclear Proteins; D004247:DNA
Ninein; asymmetric cell division; centrosome; endoplasmic reticulum; foreign DNA