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Cell Biology; Hepatitis C virus relies on cellular proliferation for genomic replication

Posted on: Thursday, 4 March 2004, 06:00 CST

2004 MAR 8 - (NewsRx.com & NewsRx.net) -- Hepatitis C virus relies on cellular proliferation for genomic replication.

"Considerable controversy surrounds the impact of hepatitis C virus (HCV) protein expression on viability of host cells and regulation of the cell cycle. Both promotion of cellular proliferation and apoptosis have been observed in different experimental systems," investigators in the United States say.

"To determine whether expression of the entire complement of HCV proteins in the context of ongoing viral RNA replication significantly alters the host cell transcriptome and cell cycle regulatory processes, we carried out high-density oligonucleotide microarray studies and analyzed cell cycle distributions and S- phase entry in Huh7 cell clones harboring selectable, full-length, replicating HCV RNAs that express the entire genotype 1b, HCV-N polyprotein, and clonally related cells in which all viral RNA was eliminated by prior treatment with alpha interferon," reported F. Scholle and colleagues, University of Texas Medical Branch.

"Oligonucleotide microarray analyses revealed only subtle, coordinated differences in the mRNA profiles of cells containing replicating viral RNA and their interferon-cured progeny, with variation between different cell clones having a greater influence on the cellular transcriptome than the presence or absence of replicating HCV RNA."

"Flow cytometric analysis demonstrated no significant differences in cell cycle distribution among populations of asynchronously growing cells of both types. Cell lines containing replicating viral RNA and their interferon-cured progeny were able to reenter the cell cycle similarly after transient G, arrest."

"In contrast, although viral protein expression and genome replication did not alter cell cycle control in these cells, HCV genome replication was highly dependent on cellular proliferation, with viral RNA synthesis strongly decreased in poorly proliferating, confluent, or serum-starved cells and substantially enhanced in the S phase of the cell cycle," scientists said.

Scholle and colleagues published their study in Journal of Virology (Virus-host cell interactions during hepatitis C virus RNA replication: Impact of polyprotein expression on the cellular transcriptome and cell cycle association with viral RNA synthesis. J Virol, 2004;78(3):1513-1524).

For additional information, contact S.M. Lemon, University Texas, Med Branch, Department Microbiology & Immunology, 5-1065 Administration Bldg, 301 University Blvd., Galveston, TX 77555, USA.

The publisher of the Journal of Virology can be contacted at: American Society for Microbiology, 1752 N St. NW, Washington, DC 20036-2904, USA.

The information in this article comes under the major subject areas of Biotechnology, Hepatitis C Virus, Hepatology, Infectious Disease, Proteomics, and Virology.

This article was prepared by Hepatitis Weekly editors from staff and other reports. Copyright 2004, Hepatitis Weekly via NewsRx.com & NewsRx.net.

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