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M9490596.TXT
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1994-09-24
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Document 0596
DOCN M9490596
TI A basis for new approaches to the chemotherapy of AIDS: novel genes in
HIV-1 potentially encode selenoproteins expressed by ribosomal
frameshifting and termination suppression.
DT 9411
AU Taylor EW; Ramanathan CS; Jalluri RK; Nadimpalli RG; Computational
Center for Molecular Structure and Design,; University of Georgia,
Athens 30602-2352.
SO J Med Chem. 1994 Aug 19;37(17):2637-54. Unique Identifier : AIDSLINE +
AB Several previously unnoticed genes in the human immunodeficiency virus
type 1 (HIV-1), potentially encoding selenoproteins, have been
discovered by analyzing the genomic RNA structure and its relation to
novel open reading frames. We have found a number of new potential RNA
pseudoknots, including one in the long terminal repeat, several that
coincide with highly conserved enzyme active site sequences in the pol
coding region, and one in the env coding region. These pseudoknots can
potentially direct the synthesis of selenocysteine (SeC) containing--1
frameshift fusion proteins. This is possible because we have found
potential SeC insertion sequences (SECIS) in the RNA of HIV and other
retroviruses; such structures are known to be necessary and sufficient
for the incorporation of SeC at UGA stop codons anywhere in a eukaryotic
mRNA. In several locations, UGA codons in the -1 reading frame are
highly conserved across a broad spectrum of primate immunodeficiency
viruses. Due to the degeneracy of the genetic code, this conservation
cannot be explained by evolutionary selection of the pol gene protein
sequence alone. Such observations, combined with the conservation of the
associated reading frames, strongly suggest that these are real genes,
and thus that the pseudoknots are also real. A protease
pseudoknot-directed -1 frameshift fusion protein contains a highly
conserved SeC codon and has significant similarities to a number of DNA
binding proteins, including papillomavirus E2 proteins, suggesting it
may be a virally encoded repressor of HIV transcription when cleaved by
protease from the rest of the gag-pol gene product. A reverse
transcriptase (RT) frameshift fusion protein replaces the RT active site
with a highly conserved SeC-containing module. An integrase frameshift
fusion protein contains the N-terminal integrase DNA-binding domain and
a potential ATP-binding GKS motif; it has significant similarities to
several helicases, but no SeC codons. A potential frameshift fusion
protein from env has one SeC codon, but not in a highly conserved
position. SeC incorporation could extend the nef gene product by 33
residues through the C-terminal UGA codon without frameshifting,
potentially leading to substantial SeC utilization in infected
cells.(ABSTRACT TRUNCATED AT 400 WORDS)
DE Acquired Immunodeficiency Syndrome/*DRUG THERAPY Amino Acid Sequence
Antiviral Agents/*CHEMICAL SYNTHESIS Base Sequence Codon Comparative
Study Conserved Sequence Drug Design DNA
Nucleotidyltransferases/BIOSYNTHESIS DNA-Binding Proteins/BIOSYNTHESIS
*Frameshift Mutation *Genes, pol *Genes, Viral Human *HIV Long
Terminal Repeat HIV-1/DRUG EFFECTS/*GENETICS Molecular Sequence Data
Nucleic Acid Conformation Proteins/*BIOSYNTHESIS Reading Frames
Recombinant Fusion Proteins/BIOSYNTHESIS Ribosomes/METABOLISM RNA,
Messenger/BIOSYNTHESIS/CHEMISTRY RNA, Viral/*BIOSYNTHESIS/CHEMISTRY
Sequence Homology, Amino Acid Support, U.S. Gov't, P.H.S. Suppression,
Genetic Viral Proteins/*BIOSYNTHESIS/GENETICS JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).