Structure determination of simian virus 40 and murine polyomavirus by a combination of 30-fold and 5-fold electron-density averaging

We have developed a method which allows determination of the direction in which replication forks move through segments of chromosomal DNA for which cloned probes are available. The method is based on the facts that DNA restriction fragments containing replication forks migrate more slowly through agarose gels than do non-fork-containing fragments and that the extent of retardation of the fork-containing fragments is a function of the extent of replication. The procedure allows the identification of DNA replication origins as sites from which replication forks diverge. In this paper we demonstrate the feasibility of this procedure, with simian virus 40 DNA as a model, and we discuss its applicability to other systems.

Download Full-text

Correction: Determination of the Number of Superhelical Turns in Simian Virus 40 DNA by Gel Electrophoresis

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.73.7.2527-e ◽

1976 ◽

Vol 73 (7) ◽

pp. 2527-2527

Keyword(s):

Gel Electrophoresis ◽

Simian Virus 40 ◽

Simian Virus

Download Full-text

Early Steps of Polyomavirus Entry into Cells

Journal of Virology ◽

10.1128/jvi.74.18.8582-8588.2000 ◽

2000 ◽

Vol 74 (18) ◽

pp. 8582-8588 ◽

Cited By ~ 54

Author(s):

Joanna M. Gilbert ◽

Thomas L. Benjamin

Keyword(s):

Jc Virus ◽

Simian Virus 40 ◽

Simian Virus ◽

Dominant Negative ◽

Independent Manner ◽

Caveolin 1 ◽

Dominant Negative Form ◽

Murine Polyomavirus ◽

Dynamin I ◽

Negative Form

ABSTRACT The mechanism by which murine polyomavirus penetrates cells and arrives at the nucleus, the site of viral replication, is not well understood. Simian virus 40 and JC virus, two closely related members of the polyomavirus subfamily, use caveola- and clathrin-mediated uptake pathways for entry, respectively. The data presented here indicate that compounds that block endocytosis of both caveola- and clathrin-derived vesicles have no effect on polyomavirus infectivity. Polyomavirus does not appear to colocalize with either clathrin light chain or caveolin-1 by immunofluorescence microscopy. Additionally, expression of a dominant-negative form of dynamin I has no effect on polyomavirus uptake and infectivity. Therefore, polyomavirus uptake occurs through a class of uncoated vesicles in a clathrin-, caveolin-1-, and dynamin I-independent manner.

Download Full-text

Cell Penetration and Trafficking of Polyomavirus

Journal of Virology ◽

10.1128/jvi.77.4.2615-2622.2003 ◽

2003 ◽

Vol 77 (4) ◽

pp. 2615-2622 ◽

Cited By ~ 48

Author(s):

Joanna M. Gilbert ◽

Ilya G. Goldberg ◽

Thomas L. Benjamin

Keyword(s):

Actin Filaments ◽

Simian Virus 40 ◽

Simian Virus ◽

Endocytic Pathway ◽

Dynamic State ◽

Cell Penetration ◽

Stabilizing Agents ◽

Virus Particles ◽

Murine Polyomavirus ◽

Microfilament System

ABSTRACT The murine polyomavirus (Py) enters mouse fibroblasts and kidney epithelial cells via an endocytic pathway that is caveola-independent (as well as clathrin-independent). In contrast, uptake of simian virus 40 into the same cells is dependent on caveola. Following the initial uptake of Py, both microtubules and microfilaments play roles in trafficking of the virus to the nucleus. Colcemid, which disrupts microtubules, inhibits the ability of Py to reach the nucleus and replicate. Paclitaxel, which stabilizes microtubules and prevents microtubule turnover, has no effect, indicating that intact but not dynamic microtubules are required for Py infectivity. Compounds that disrupt actin filaments enhance Py uptake while stabilization of actin filaments impedes Py infection. Virus particles are seen in association with actin in cells treated with microfilament-disrupting or filament-stabilizing agents at levels comparable to those in untreated cells, suggesting that a dynamic state of the microfilament system is important for Py infectivity.

Download Full-text