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M9650333.TXT
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1996-03-09
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Document 0333
DOCN M9650333
TI Ribonuclease H activity during initiation of reverse transcription using
tRNA(lys)/RNA primer/template of human immunodeficiency virus.
DT 9605
AU Artzi HB; Shemesh J; Zeelon E; Amit B; Kleiman L; Gorecki M; Panet A;
Bio-Technology General Israel, Ltd., Kiryat Weizmann, Rehovot,; Israel.
SO Arch Biochem Biophys. 1996 Jan 15;325(2):209-16. Unique Identifier :
AIDSLINE MED/96139301
AB The specificity of the initial cleavage by the RNaseH activity of HIV-1
reverse transcriptase (RT) during minus strong-stop DNA synthesis was
studied using the authentic primer/template tRNA(lys)/HIV RNA. We
observed that concomitant with the initiation of DNA synthesis, RNaseH
activity of HIV RT introduced the first endonucleolytic cuts within the
U5 region of the HIV RNA template, mainly 1 and 3 bases away from the
primer binding site. To analyze whether the cleavage sites were
determined by sequence specificity, the authentic U5 region at one of
the cleavage sites was mutated. The change of sequence did not alter the
initial cleavage pattern of RNaseH. In order to determine the size of
the RNA/DNA hybrid that is required for RNaseH activation during reverse
transcription initiation, DNA synthesis was limited by
dideoxynucleotides. DNA extension of the tRNA(lys) primer by 17
deoxyribonucleotides but not by 6 deoxyribonucleotides was sufficient to
activate the RNaseH site of HIV RT. Taken together, our results indicate
that during initiation of minus strongstop DNA synthesis by HIV RT, the
first RNaseH-mediated endonucleolytic cut of the genomic RNA is dictated
mainly by the length of the nascent DNA and not by sequence preference.
DE Base Sequence Binding Sites DNA, Viral/BIOSYNTHESIS/GENETICS Enzyme
Activation Human HIV-1/GENETICS/*METABOLISM In Vitro Molecular
Sequence Data Ribonuclease H, Calf Thymus/*METABOLISM RNA/*GENETICS
RNA-Directed DNA Polymerase/*METABOLISM RNA, Transfer,
Lys/GENETICS/*METABOLISM RNA, Viral/CHEMISTRY/GENETICS/*METABOLISM
Support, U.S. Gov't, P.H.S. Transcription, Genetic JOURNAL ARTICLE
SOURCE: National Library of Medicine. NOTICE: This material may be
protected by Copyright Law (Title 17, U.S.Code).