Previous Article | Next Article ![]()
J. Virol., 06 1997, 4254-4263, Vol 71, No. 6
JG Julias, T Kim, G Arnold and VK Pathak
It was previously observed that the nucleoside analog 5-azacytidine
increased the spleen necrosis virus (SNV) mutation rate 13-fold in one
cycle of retrovirus replication (V. K. Pathak and H. M. Temin, J. Virol.
66:3093-3100, 1992). Based on this observation, we hypothesized that
nucleoside analogs used as antiviral drugs may also increase retrovirus
mutation rates. We sought to determine if 3'-azido-3'- deoxythymidine
(AZT), the primary treatment for human immunodeficiency virus type 1
(HIV-1) infection, increases the retrovirus mutation rate. Two assays were
used to determine the effects of AZT on retrovirus mutation rates. The
strategy of the first assay involved measuring the in vivo rate of
inactivation of the lacZ gene in one replication cycle of SNV- and murine
leukemia virus-based retroviral vectors. We observed 7- and 10-fold
increases in the SNV mutant frequency following treatment of target cells
with 0.1 and 0.5 microM AZT, respectively. The murine leukemia virus mutant
frequency increased two- and threefold following treatment of target cells
with 0.5 and 1.0 microM AZT, respectively. The second assay used an
SNV-based shuttle vector containing the lacZ alpha gene. Proviruses were
recovered as plasmids in Escherichia coli, and the rate of inactivation of
lacZ alpha was measured. The results indicated that treatment of target
cells increased the overall mutation rate two- to threefold. DNA sequence
analysis of mutant proviruses indicated that AZT increased both the
deletion and substitution rates. These results suggest that AZT treatment
of HIV-1 infection may increase the degree of viral variation and alter
virus evolution or pathogenesis.
Copyright © 1997, American Society for Microbiology
The antiretrovirus drug 3'-azido-3'-deoxythymidine increases the retrovirus mutation rate
Department of Biochemistry, Mary Babb Randolph Cancer Center, West Virginia University, Morgantown 26506, USA.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»