Asymmetric partitioning of transfected DNA during mammalian cell division

Abstract

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.foreign DNA | asymmetric cell division | centrosome | endoplasmic reticulum | Ninein G enerally, noncentromeric DNA molecules are mitotically instable in eukaryotes. This results in their apparent disappearance from an ever-increasing proportion of the progeny of an affected cell (e.g., 1-3). Endogenous sources of such DNA are recombination byproducts [double minutes, extrachromosomal ribosomal (r)DNA circles (ERCs) and other DNA circles (3-6)] or mitotic defects generating noncentromeric chromosomal fragments and cytoplasmic micronuclei (1, 7). Exogenous sources are DNA of pathogens or DNA, typically plasmids, artificially introduced into cells. For the latter, decades of work established that plasmid-born protein expression is transient, persisting only for a few cell cycles (8). This finding is consistent with plasmid DNA being somehow eliminated through divisions. Thus, some mechanisms seem to prevent the propagation of foreign DNA and extrachromosomal DNA in proliferating eukaryotic cells. However, how this is achieved is unclear.In animal cells, DNA sensors mediate the early detection of exogenous DNA, such as DNA of invading pathogens and artificially introduced DNA (9-11). Both in leukocytes and nonprofessional immune cells, these can trigger innate immune responses, such as cytokine production, autophagy, and apoptosis (9). However, what happens to the DNA molecules themselves over time is unclear. When microi...

Proliferation of primary human hepatocytes and prevention of hepatitis B virus reinfection efficiently deplete nuclear cccDNA in vivo

“…Because the cccDNA is an extrachromosomal plasmid-like structure lacking centromeres, mitosis may accelerate its loss 38 39. By employing USB mice, we demonstrate that in vivo proliferation of HBV-infected human hepatocytes provokes a dramatic decrease of intrahepatic cccDNA contents.…”

Asymmetry of nanoparticle inheritance upon cell division: Effect on the coefficient of variation

“…In this context, it has repeatedly been observed that when cells divide, the nanoparticles they have taken up are shared between the resulting daughter cells in an asymmetrical fashion [12][13][14][15][16][17][18][19][20][21][22], that is, one daughter cell receiving more of the nanoparticles from the mother than the other daughter cell. Evidence for such an asymmetry includes fits of computational [13,14] and theoretical [15,16,20] models to experimental data, as well as more direct observations by tediously imaging individual cells as they divide and subsequently tracking the nanoparticle inheritance pattern of the daughter cells [19][20][21][22].…”

New dimensions of asymmetric division in vertebrates

“…An interesting aspect of the asymmetric inheritance of DNA was shown in a recent study, demonstrating cells tendency to eliminate foreign DNA molecules by asymmetrically segregating them into the daughter cell that inherits the younger centrosome (Wang, Le, Denoth-Lippuner, Barral, & Kroschewski, 2016). Transfected DNA clustered around the endoplasmic reticulum and later, around the centrosome during mitosis.…”