Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Query: EC:3.1.26.4 (
RNase H
)
2,751
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Tax, the trans-activating protein of
bovine leukemia
virus, stimulates the long terminal repeat to promote viral transcription and also activates cellular genes that may be involved in tumorigenesis. To study Tax regulation, we identified antisense oligodeoxynucleotides that inhibit tax translation in rabbit reticulocyte lysate. Two antisense oligonucleotides directed toward the 5' end of tax RNA inhibited translation by 59% and 45%, when compared to the effect of a random sequence oligonucleotide. This inhibitory effect was independent of
RNase H
. In contrast, antisense directed at the middle of the tax RNA inhibited by only 12%, but, in the presence of
RNase H
, inhibited 38%. An antisense oligonucleotide directed at the 3' portion of tax RNA was not inhibitory and, in fact, stimulated translation. Identification of these inhibitory antisense sequences may allow elucidation of the biological role of Tax in BLV-persistent lymphocytosis and tumorigenesis.
...
PMID:Antisense oligonucleotide inhibition of bovine leukemia virus tax expression in a cell-free system. 132 33
We have expressed the recombinant reverse transcriptase (RT) of
bovine leukemia
virus (BLV) in bacteria. The gene encoding the RT was designed to start at its 5' end next to the last codon of the mature viral protease, namely the amino terminus of the RT matches the last 26 codons of the pro gene and is coded for by the pro reading frame. The RT sequence extends into the pol gene, utilizing the pol reading frame after overcoming the stop codon by adding an extra nucleotide (thus imitating the naturally occurring frameshift event). Hence we have generated a transframe polypeptide that is a 584-residues-long protein (see Rice, Stephens, Burny, and Gilden (1985) Virology 142, 357-377). This protein was partially purified after adding a six-histidine tag and studied biochemically testing a variety of parameters. The enzyme exhibits all activities typical of RTs, i.e., both RNA- and DNA-dependent DNA polymerase as well as a
ribonuclease H
(
RNase H
) activity. Unlike most RTs, the BLV RT is enzymatically active as a monomer even after binding a DNA substrate. The enzyme shows a preference for Mg2+ over Mn2+ in both its DNA polymerase and
RNase H
activities. BLV RT is relatively resistant to nucleoside triphosphate analogues, which are known to be potent inhibitors of other RTs such as that of HIV.
...
PMID:Catalytic features of the recombinant reverse transcriptase of bovine leukemia virus expressed in bacteria. 1036 2
Bovine leukemia
virus (BLV) is the causative agent of enzootic bovine leucosis (EBL), to which animals are most susceptible at 4-8 years of age. In this study, we examined tumor cells associated with EBL in an 18-year-old cow to reveal that the cells carried at least two different copies of the virus, one of which was predicted to encode a reverse transcriptase (RT) lacking
ribonuclease H
activity and no integrase. Such a deficient enzyme may exhibit a dominant negative effect on the wild-type RT and cause insufficient viral replication, resulting in delayed tumor development in this cow.
...
PMID:Delayed-onset enzootic bovine leukosis possibly caused by superinfection with bovine leukemia virus mutated in the pol gene. 2602 55
