home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Shareware Overload Trio 2
/
Shareware Overload Trio Volume 2 (Chestnut CD-ROM).ISO
/
dir26
/
med9409c.zip
/
M9490428.TXT
< prev
next >
Wrap
Text File
|
1994-09-19
|
3KB
|
47 lines
Document 0428
DOCN M9490428
TI A molecular rheostat. Co-operative rev binding to stem I of the
rev-response element modulates human immunodeficiency virus type-1 late
gene expression.
DT 9411
AU Mann DA; Mikaelian I; Zemmel RW; Green SM; Lowe AD; Kimura T; Singh M;
Butler PJ; Gait MJ; Karn J; MRC Laboratory of Molecular Biology,
Cambridge, U.K.
SO J Mol Biol. 1994 Aug 12;241(2):193-207. Unique Identifier : AIDSLINE
MED/94334977
AB The complete biologically active human immunodeficiency virus type-1
(HIV-1) rev-response element (RRE) RNA is 351 nucleotides (nt) in
length, and includes an extra 58 nt on the 5' end and 59 nt on the 3'
end beyond the sites proposed in the original models for the RRE
secondary structure. The extra sequences are able to form a duplex
structure which extends Stem I. The presence of an elongated Stem I
structure in the RRE RNA was confirmed by nuclease mapping experiments.
Nuclease protection experiments have shown that rev binds to restricted
regions of the RRE, including the high affinity site located at the base
of Stem IIb and along the length of the Stem I region. The three large
stem-loop structures which protrude from Stem I and Stem IIb (Stems IIc,
III+IV and V) remain accessible to nucleases even in the presence of a
large excess of protein. Gel-retardation experiments show that the
truncations of Stem I reduced the total number of rev molecules that can
bind co-operatively and with high affinity to the RRE RNA. To test
whether the elongated Stem I structure is required for maximal rev
activity, a series of truncations which progressively reduced the length
of Stem I was introduced into an HIV-1 derived reporter plasmid. In the
presence of rev and a functional RRE, there is an increase in the levels
of gag and env mRNA in the cytoplasm and a decrease in levels of tat and
rev mRNAs. Each of the truncations in Stem I reduced the rev responses,
with the longest truncations producing the greatest losses of activity.
The data suggest that the RRE acts as a molecular rheostat designed to
detect rev levels during the early stages of the HIV growth cycle.
DE Base Sequence Binding Sites Electrophoresis, Polyacrylamide Gel Gene
Expression Regulation, Viral/*GENETICS Gene Products, rev/*METABOLISM
Genes, env/*GENETICS Genes, gag/GENETICS Genes, tat/GENETICS Hela
Cells Human HIV-1/*GENETICS Molecular Sequence Data Mutagenesis
Nucleic Acid Conformation Polymerase Chain Reaction RNA,
Viral/CHEMISTRY/*GENETICS/METABOLISM Support, Non-U.S. Gov't
Transfection JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).