scholarly journals Macromolecular Uptake Is a Spontaneous Event during Mitosis in Cultured Fibroblasts: Implications for Vector-dependent Plasmid Transfection

2002 ◽  
Vol 13 (2) ◽  
pp. 570-578 ◽  
Author(s):  
Pierre Pellegrin ◽  
Anne Fernandez ◽  
Ned J. C. Lamb ◽  
René Bennes

The process through which macromolecules penetrate the plasma membrane of mammalian cells remains poorly defined. We have examined whether natural cellular events modulate the capacity of cells to take up agents applied extraneously. Herein, we report that during mitosis and in a cell type-independent manner, cells exhibit a natural ability to absorb agents present in the extracellular environment up to 150 kDa as assessed using fluorescein isothiocyanate-dextrans. This event is exclusive to the mitotic period and not observed during G0, G1, S, or G2 phase. During mitosis, starting in advanced prophase, oligonucleotides, active enzymes, and polypeptides are efficiently taken into mitotic cells. This uptake of macromolecules during mitosis still takes place in the presence of cytochalasin D or nocodazole, showing no requirement for intact microtubules or actin filaments in this process. However, cell rounding up, which still takes place in the presence of either of these drugs in mitotic cells, appears to be a key event in this process. Indeed, limited trypsinization of adherent cells mimics both the cell retraction and macromolecule uptake observed as cells enter mitosis. A plasmid DNA encoding green fluorescent protein (3.3Mda) coated with an 18 amino acid peptide is efficiently expressed when applied onto synchronized G2/M fibroblasts, whereas little or no expression is observed when the coated plasmid is applied onto asynchronous cell cultures. This shows that such coating peptides are only efficient for their encapsulating and protective effect on the plasmid DNA to be “vectorized” rather than acting as true vectors.

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Jinghua Duan ◽  
Yangde Zhang ◽  
Wei Chen ◽  
Chengrong Shen ◽  
Mingmei Liao ◽  
...  

To enhance the intracellular delivery potential of plasmid DNA using nonviral vectors, we used polybutyl cyanoacrylate (PBCA) and chitosan to prepare PBCA nanoparticles (NPs) by emulsion polymerization and prepared NP/DNA complexes through the complex coacervation of nanoparticles with the DNA. The object of our work is to evaluate the characterization and transfection efficiency of PBCA-NPs. The NPs have a zeta potential of 25.53 mV at pH 7.4 and size about 200 nm. Electrophoretic analysis suggested that the NPs with positive charges could protect the DNA from nuclease degradation and cell viability assay showed that the NPs exhibit a low cytotoxicity to human hepatocellular carcinoma (HepG2) cells. Qualitative and quantitative analysis of transfection in HepG2 cells by the nanoparticles carrying plasmid DNA encoding for enhanced green fluorescent protein (EGFP-N1) was done by digital fluorescence imaging microscopy system and fluorescence-activated cell sorting (FACS). Qualitative results showed highly efficient expression of GFP that remained stable for up to 96 hours. Quantitative results from FACS showed that PBCA-NPs were significantly more effective in transfecting HepG2 cells after 72 hours postincubation. The results of this study suggested that PBCA-NPs have favorable properties for nonviral delivery.


2000 ◽  
Author(s):  
Molly B. James ◽  
Todd D. Giorgio

Abstract Intracellular plasmid is rapidly incorporated into the nucleus of HeLa cells following cationic lipoplex transfection. CV1 cells are less effective in translocating plasmid to the nucleus and also express less transgene than HeLa cells. Cultured HeLa and CV1 cells and corresponding isolated nuclei were analyzed after transfection of a Cy3 labeled pGreenLantern plasmid (Cy3-pGL). Flow cytometry was used to measure both plasmid delivery and transgene expression from the plasmid encoding a CMV promoter driven green fluorescent protein. During transfection, HeLa cells rapidly incorporated the plasmid, reaching a maximum of 80% Cy3-pGL positive cells 8 hours post-transfection. The average Cy3-pGL positive HeLa cell contained approximately 2470 plasmid copies. 48% of the nuclei isolated from the transfected HeLa cells were positive for the plasmid marker after 8 hours. In contrast to HeLa cells, fewer CV1 cells and CV1 nuclei incorporated plasmid DNA with peak transfection occurring after 12 hours for 36% of the cells and after 8 hours for 12% of the nuclei. However, the average Cy3-pGL positive CV1 cell did not have a significantly different number of total cellular plasmid copies than the average positive HeLa cell. CV1 nuclei, however, had half as much plasmid as HeLa nuclei. HeLa cells are more efficient than CV1 cells at transporting plasmid from the cytoplasm to the nucleus. This study demonstrates the use of a novel quantitative method to study plasmid transport from the cytoplasm to nucleus and the effect on transgene expression.


2006 ◽  
Vol 17 (11) ◽  
pp. 4606-4618 ◽  
Author(s):  
Cezary Wójcik ◽  
Maga Rowicka ◽  
Andrzej Kudlicki ◽  
Dominika Nowis ◽  
Elizabeth McConnell ◽  
...  

Valosin-containing protein (VCP; p97; cdc48 in yeast) is a hexameric ATPase of the AAA family (ATPases with multiple cellular activities) involved in multiple cellular functions, including degradation of proteins by the ubiquitin (Ub)–proteasome system (UPS). We examined the consequences of the reduction of VCP levels after RNA interference (RNAi) of VCP. A new stringent method of microarray analysis demonstrated that only four transcripts were nonspecifically affected by RNAi, whereas ∼30 transcripts were affected in response to reduced VCP levels in a sequence-independent manner. These transcripts encoded proteins involved in endoplasmic reticulum (ER) stress, apoptosis, and amino acid starvation. RNAi of VCP promoted the unfolded protein response, without eliciting a cytosolic stress response. RNAi of VCP inhibited the degradation of R-GFP (green fluorescent protein) and Ub-G76V-GFP, two cytoplasmic reporter proteins degraded by the UPS, and of α chain of the T-cell receptor, an established substrate of the ER-associated degradation (ERAD) pathway. Surprisingly, RNAi of VCP had no detectable effect on the degradation of two other ERAD substrates, α1-antitrypsin and δCD3. These results indicate that VCP is required for maintenance of normal ER structure and function and mediates the degradation of some proteins via the UPS, but is dispensable for the UPS-dependent degradation of some ERAD substrates.


2001 ◽  
Vol 12 (8) ◽  
pp. 2245-2256 ◽  
Author(s):  
Elena Smirnova ◽  
Lorena Griparic ◽  
Dixie-Lee Shurland ◽  
Alexander M. van der Bliek

Mutations in the human dynamin-related protein Drp1 cause mitochondria to form perinuclear clusters. We show here that these mitochondrial clusters consist of highly interconnected mitochondrial tubules. The increased connectivity between mitochondria indicates that the balance between mitochondrial division and fusion is shifted toward fusion. Such a shift is consistent with a block in mitochondrial division. Immunofluorescence and subcellular fractionation show that endogenous Drp1 is localized to mitochondria, which is also consistent with a role in mitochondrial division. A direct role in mitochondrial division is suggested by time-lapse photography of transfected cells, in which green fluorescent protein fused to Drp1 is concentrated in spots that mark actual mitochondrial division events. We find that purified human Drp1 can self-assemble into multimeric ring-like structures with dimensions similar to those of dynamin multimers. The structural and functional similarities between dynamin and Drp1 suggest that Drp1 wraps around the constriction points of dividing mitochondria, analogous to dynamin collars at the necks of budding vesicles. We conclude that Drp1 contributes to mitochondrial division in mammalian cells.


1999 ◽  
Vol 112 (16) ◽  
pp. 2705-2714
Author(s):  
E.M. Burns ◽  
L. Christopoulou ◽  
P. Corish ◽  
C. Tyler-Smith

We have measured the mitotic loss rates of mammalian chromosomes in cultured cells. The green fluorescent protein (GFP) gene was incorporated into a non-essential chromosome so that cells containing the chromosome fluoresced green, while those lacking it did not. The proportions of fluorescent and non-fluorescent cells were measured by fluorescence activated cell sorter (FACS) analysis. Loss rates ranged from 0.005% to 0.20% per cell division in mouse LA-9 cells, and from 0.02% to 0.40% in human HeLa cells. The rate of loss was elevated by treatment with aneugens, demonstrating that the system rapidly identifies agents which induce chromosome loss in mammalian cells.


1997 ◽  
Vol 136 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Erik A.C. Wiemer ◽  
Thibaut Wenzel ◽  
Thomas J. Deerinck ◽  
Mark H. Ellisman ◽  
Suresh Subramani

Peroxisomes in living CV1 cells were visualized by targeting the green fluorescent protein (GFP) to this subcellular compartment through the addition of a COOH-terminal peroxisomal targeting signal 1 (GFP–PTS1). The organelle dynamics were examined and analyzed using time-lapse confocal laser scanning microscopy. Two types of movement could be distinguished: a relatively slow, random, vibration-like movement displayed by the majority (∼95%) of the peroxisomes, and a saltatory, fast directional movement displayed by a small subset (∼5%) of the peroxisomes. In the latter instance, peak velocities up to 0.75 μm/s and sustained directional velocities up to 0.45 μm/s over 11.5 μm were recorded. Only the directional type of motion appeared to be energy dependent, whereas the vibrational movement continued even after the cells were depleted of energy. Treatment of cells, transiently expressing GFP–PTS1, with microtubule-destabilizing agents such as nocodazole, vinblastine, and demecolcine clearly altered peroxisome morphology and subcellular distribution and blocked the directional movement. In contrast, the microtubule-stabilizing compound paclitaxel, or the microfilament-destabilizing drugs cytochalasin B or D, did not exert these effects. High resolution confocal analysis of cells expressing GFP–PTS1 and stained with anti-tubulin antibodies revealed that many peroxisomes were associated with microtubules. The GFP–PTS1–labeled peroxisomes were found to distribute themselves in a stochastic, rather than ordered, manner to daughter cells at the time of mitosis.


2008 ◽  
Vol 20 (1) ◽  
pp. 235
Author(s):  
S. J. Uhm ◽  
M. K. Gupta ◽  
T. Kim ◽  
H. T. Lee

We have demonstrated previously that retroviral-mediated gene transfer is a promising method to produce transgenic avian, porcine, and bovine embryos. This study was designed to evaluate the development potential of transgenic porcine embryos produced by somatic cell nuclear transfer (SCNT) of fetal fibroblast (pFF) cells transfected by a robust replication-defective retroviral vector harboring enhanced green fluorescent protein (EGFP) or β-galactosidase (LacZ) gene. Moloney murine leukemia virus (MoMLV)-based retroviral vectors encapsidated with VSV-G (vesicular stomatitis virus G) glycoprotein and harboring EGFP or LacZ under the control of β-actin promoter were produced and used to transfect primary pFF cells that were subsequently used for SCNT of enucleated porcine oocytes matured in vitro. Our results showed that all surviving cells after transfection and antibiotic selection expressed the genes without any evidence of replication-competent retrovirus. The fusion, cleavage, and blastocyst rates were 85.6 � 6.5, 53.6 � 6.4, and 12.0 � 5.7% for EGFP; 83.5 � 8.2, 57.5 � 6.3 and 10.1 � 4.1% for LacZ; and 80.5 � 4.2, 60.9 � 8.2 and 12.3 � 4.0% for controls, respectively. Mosaicism was not observed in any of the group as evidenced by the expression of LacZ or EGFP in individual blastomeres of all embryos upon staining with β-galactosidase (for LacZ) or when visualized under UV illumination of an epifluorescent microscope using the fluorescein isothiocyanate (FITC) filter set (for EGFP). Further recloning of EGFP-expressing blastomeres, obtained from 4-cell-stage cloned embryos produced by SCNT of pFF cells infected with EGFP harboring vector, into enucleated metaphase II (MII) oocytes resulted in consistent expression of EGFP in recloned blastocysts. Interspecies SCNT (iSCNT) of transfected pFF into enucleated bovine oocytes could also result in consistent gene expression without any adverse effect on blastocyst rate (5.5 v. 4.9%) compared with non-transfected pFF. These data indicate that the replication-defective retroviral vector used in the present study is robust and independent of the genes inserted. Furthermore, introduction of transgenes by this method does not influence the in vitro development rate of cloned embryos. This work was supported by a grant from Biogreen 21 Program, RDA, Republic of Korea.


2018 ◽  
Vol 194 ◽  
pp. 29-39 ◽  
Author(s):  
Fatemeh Motevalli ◽  
Azam Bolhassani ◽  
Shilan Hesami ◽  
Sepideh Shahbazi

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