Previous Article | Next Article ![]()
J. Virol., 07 1997, 5088-5094, Vol 71, No. 7
DJ Leisy, C Rasmussen, EO Owusu and GF Rohrmann
The Autographa californica multinucleocapsid nuclear polyhedrosis virus
(AcMNPV) ie-1 gene product (IE-1) is thought to play a central role in
stimulating early viral transcription. IE-1 has been demonstrated to
activate several early viral gene promoters and to negatively regulate the
promoters of two other AcMNPV regulatory genes, ie-0 and ie-2. Our results
indicate that IE-1 negatively regulates the expression of certain genes by
binding directly, or as part of a complex, to promoter regions containing a
specific IE-1-binding motif (5'-ACBYGTAA-3') near their mRNA start sites.
The IE-1 binding motif was also found within the palindromic sequences of
AcMNPV homologous repeat (hr) regions that have been shown to bind IE-1.
The role of this IE-1 binding motif in the regulation of the ie-2 and pe-38
promoters was examined by introducing mutations in these promoters in which
the central 6 bp were replaced with BglII sites. GUS reporter constructs
containing ie-2 and pe-38 promoter fragments with and without these
specific mutations were cotransfected into Sf9 cells with various amounts
of an ie-1-containing plasmid (pIe-1). Comparisons of GUS expression
produced by the mutant and wild-type constructs demonstrated that the IE-1
binding motif mediated a significant decrease in expression from the ie-2
and pe-38 promoters in response to increasing pIe-1 concentrations.
Electrophoretic mobility shift assays with pIe-1-transfected cell extracts
and supershift assays with IE-1-specific antiserum demonstrated that IE-1
binds to promoter fragments containing the IE-1 binding motif but does not
bind to promoter fragments lacking this motif.
Copyright © 1997, American Society for Microbiology
A mechanism for negative gene regulation in Autographa californica multinucleocapsid nuclear polyhedrosis virus
Department of Microbiology, Oregon State University, Corvallis 97331- 7301, USA. leisyd@bcc.orst.edu
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»