Previous Article | Next Article ![]()
Molecular and Cellular Biology, April 2001, p. 2826-2837, Vol. 21, No. 8
Molecular Biology Institute, University of
California,1 and Department of
Microbiology, Immunology and Molecular Genetics, UCLA School of
Medicine,2 Los Angeles, California 90095
Received 22 September 2000/Returned for modification 27 November
2000/Accepted 30 January 2001
We report here a novel fluorescent protein-based screen to identify
small, synthetic internal ribosome entry site (IRES) elements in vivo.
A library of bicistronic plasmids encoding the enhanced blue and green
fluorescent proteins (EBFP and EGFP) separated by randomized
50-nucleotide-long sequences was amplified in bacteria and delivered
into mammalian cells via protoplast fusion. Cells that received
functional IRES elements were isolated using the EBFP and EGFP
reporters and fluorescence-activated cell sorting, and several small
IRES elements were identified. Two of these elements were subsequently
shown to possess IRES activity comparable to that of a variant of the
encephalomyocarditis virus IRES element in a context-independent manner
both in vitro and in vivo, and these elements functioned in multiple
cell types. Although no sequence or structural homology was apparent
between the synthetic IRES elements and known viral and cellular IRES
elements, the two synthetic IRES elements specifically blocked
poliovirus (PV) IRES-mediated translation in vitro. Competitive
protein-binding experiments suggested that these IRES elements compete
with PV IRES-mediated translation by utilizing some of the same factors as the PV IRES to direct translation. The utility of this fluorescent protein-based screen in identifying IRES elements with improved activity as well as in probing the mechanism of IRES-mediated translation is discussed.
0270-7306/01/$04.00+0 DOI: 10.1128/MCB.21.8.2826-2837.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
Novel Fluorescence-Based Screen To Identify Small
Synthetic Internal Ribosome Entry Site Elements
*
Corresponding author. Mailing address: Dept. of
Microbiology, Immunology and Molecular Genetics, UCLA School of
Medicine, Los Angeles, CA 90095. Phone: (310) 206-8649. Fax: (310)
206-3865. E-mail: dasgupta{at}ucla.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»