Virus avian myeloblastosis

After obtaining pure total RNA from eukaryotic cells, the RNA needs to be rewritten into cDNA to serve as a template in PCR, as RNA cannot be amplified by PCR. The task of rewriting is accomplished with reverse transcriptase (RT), a viral enzyme used by retroviruses (whose name stems from harboring this enzyme and the ability to rewrite RNA into cDNA). The group of retroviruses has such members as the AIDS virus, Avian myeloblastosis virus, Murine leukemia virus (Frohmann, 1988 Kawasaki, 1988), and Adenovirus. Commonly employed reverse transcriptases stem from either the avian virus (AMV-RT) or the murine leukemia virus (MMLV, used in the Clontech RT-kit). 

Virus, adeno- 144, 154, 156 —, avian myeloblastosis 143 —, fowl plaque 144, 154 —, hamster melanoma 143... 

Boyle, W.J., Lipsick, J.S., Reddy, E.R, and Baluda, M.A. (1983) Identification of the leukemogenic protein of avian myeloblastosis virus and of its normal cellular homologue. Proc. Natl. Acad. Sci. USA 80, 2834-2838. 

The detection of HIV-related proteins is one of the most challenging tasks. This is especially true because AIDS should be diagnosed as early as possible to enable an early and effective therapy of this infection. Pavski and Le (57) used the aptamer strategy to detect reverse transcriptase (RT) of the type 1 human immunodeficiency virus (HIV-1). A direct and specific ACE method was proposed using laser-induced fluorescence (ACE/LIF) as detection principle. Single-stranded DNA aptamers as probes fluorescently labeled were synthesized. The resulting aptamer is specific for HIV-1 RT, and it exhibited no cross-reactivity with RTs of the enhanced avian myeloblastosis virus (AMV), the Moloney murine leukemia virus (MMLV), or denatured HIV-1 RT. An affinity complex of RT 26-HIV-l RT was stable, with calibration curves linear up to 50 nM (6 /xg/mL) HIV-1 RT concentration. Both... 

Moreover, the same extract has inhibited the replication of HIV-1 in infected MT-4 cells [107] and moderately inhibited avian myeloblastosis virus-reverse transcriptase [108], These investigations suggest that the anti-HIV effect of the methanol extract of Swietenia mahagoni seems to be due to inhibition of HIV-protease by chlorogenic acids. 

Selected naturally occurring flavonoids have been shown to inhibit three reverse transcriptases (RT) (avian myeloblastosis RT, Rous-associated virus-2 RT, and Moloney murine leukemia virus, or MMLV, RT) when poly(rA)oligo(dT) 12-18 or rabbit globin mRNA was used as a template. Amentoflavone, scutellarein, and quercetin were the most active compounds, and their effect was concentration dependent. The enzymes exhibited differential sensitivity to the inhibitory effects of the flavonoids. These flavonoids also inhibited rabbit globin mRNA-directed MMLV RT-catalyzed... 

Pretazettine (395) has been the subject of numerous biological studies, and it has been shown to exhibit a number of interesting activities (96,97,101,178-187). For example, 395 was found to inhibit HeLa cell growth as well as protein synthesis in eukaryotic cells by interfering with the peptide bond formation step (97,101). Furthermore, pretazettine inhibited the purified RNA-dependent DNA polymerase (reverse transcriptase) from avian myeloblastosis virus, a typical C-type virus (178), in an unusual fashion since it physically combined with the polymerase enzyme itself rather than interacted with the nucleic acid template. Pretazettine also exhibited antiviral activity against the Rauscher leukemia virus in mouse embryo cell cultures by suppressing viral replication (179). 

In 1994, six novel drimane-type sesquiterpenoids, mniopetals A-F (1-6) (Fig. (1)), were isolated by Anke and Steglich from the fermentation broth of Canadian Mniopetalum sp. 87256 [1, 2]. These natural products are known to inhibit the enzymatic activity of RNA-directed DNA-polymerases (reverse transcriptases) of the human immunodeficiency virus (HIV)-l, avian myeloblastosis virus (AMV), and moloney murine leukemia virus (MMuLV) as shown in Table 1. In addition, mniopetals exhibit moderate antimicrobial and cytotoxic activities. In the following year, a structurally and biologically similar natural product kuehnero-... 

Enzyme isolated from Avian Myeloblastosis virus... 

Avian myeloblastosis virus (AMV) reverse transcriptase (AMV RT-XL 17 U///1) is purchased from Life Sciences Inc. (St. Petersburg, FL) the enzyme is aliquoted and stored at —20°... 

AMV, avian myeloblastosis virus AND-R, androgen receptor ANF, atrial natriuretic factor ANP, atrial natriuretic peptide... 

Conditions for optimal recoveries of poly(A) containing RNA, with minimal contamination from rRNA, were investigated. The poly(A) fractions isolated were effective as an RNA template for the synthesis of complementary DNA with the RNA-dependent DNA polymerase of avian myeloblastosis virus. Poly(dT)-cellulose has also been used both in the purification of a 14 S messenger RNA for the immunoglobulin light chain from microsomes of MOPC 41 mouse myeloma that appeared to code for a precursor protein [117], and in the purification of RNA-dependent DNA polymerase from RNA tumour virus [118]. An example of the use of oligo(dT)-cellulose is provided by the purification of a viral specific RNA from sarcoma virus-transformed nonproducer cells [119]. 

Analyses of in situ DNA synthesis of Euglena gracilis identify zinc-dependent steps in the eukaryotic cell cycle and show that the derangements in RNA metabolism are critical determinants of the growth arrest associated with zinc deficiency. Combined use of microwave-induced emission spectrometry and micro gel emulsion chromatography shows the presence of stoichiometric amounts of zinc essential to the function of E. gracilis and yeast RNA polymerases, the reverse transcriptases" from avian myeloblastosis, murine leukemic and woolly type C viruses, and E. coli methionyl tRNA synthetase. These results stress the importance of zinc to both nucleic acid and protein metabolism. Transient-state kinetic studies of carboxypeptidase A show that zinc functions in the catalytic step of peptide hydrolysis and in the binding step of ester hydrolysis. 

Stromberg, K., Hurley, N. E., Davis, N. L., Rueckert, R. R and Fleissner, E. (1974) Structural studies of avian myeloblastosis virus comparison of polypeptides in virion and core component by dodecyl sulfate-polyacrylamide gel electrophoresis.. /. Virol. 13, 513-528. 

Reverse transcription of RNA is sometimes used, e.g., for clone selection by colony hybridization (Verbeek and Tijssen, 1988). Although both avian myeloblastosis virus (AMV) and Moloney murine leukemia virus (MMLV) reverse transcriptase can be used, we prefer the AMV enzyme if there are no strong secondary structures in the RNA (MMLV enzyme can be used at higher temperatures, even up to 55°C). The optimal pH range for the AMV enzyme is very narrow (should be 8.3) whereas the MMLV enzyme is active in a range of 7.6-8.3. Superscript reverse transcriptase from BRL is a cloned MMLV enzyme from which the RNase H activity has been deleted. 

Assays based on sandwich-hybridization are available in several platforms, such as sequential injection analysis (55), microtiter plate assays (61), and microfluidic devices (62). The LFA biosensor assays described in this chapter rely on the sandwich-hybridization of a nucleic acid sequence based amplified (NASBA) RNA target between a membrane immobilized capture probe and SRB-encapsulating liposome conjugated reporter probe. NASBA uses the enzymes avian myeloblastosis virus reverse transcriptase (AMV-RT), RNaseH, and T7 DNA dependent RNA polymerase in the presence of deoxyribonucleoside triphosphates and appropriate primers to amplify relatively few copies of target RNA into... 

Recent experimental data have also shown that resorcinolic lipids, including alkylresorcinols and their derivatives at a concentration level of micrograms/ml inhibit competitively the reverse transcriptase of mice leukemia viruses and avian myeloblastosis [338,339]. 

In the midst of the societal and scientific maelstrom created by the AIDS epidemic, a noteworthy paper by Inouye and collaborators appeared in the January 1987 issue of the Journal of Antibiotics Thus, three natural products known as luzopeptins A, 2, B, 3, and C, 4, were found to possess significant inhibitory activity against RT from the avian myeloblastosis virus (AMV). 

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