Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0679427 (myeloblastosis)
 982 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribtuion of various amino acid tRNA's in the 4S RNA components of avian myeloblastosis virus (AMV) and in 4S RNA prepared from chicken cmbryo cells, chicken myeloblasts, and chicken livers was determined. This was done by aminoacylating the 4S RNA samples with a mixture of 17 radioactive amino acids and subsequently identifying the tRNA-accepted amino acids on an amino acid analyzer after deacylation. In embryo cells, myeloblasts, and liver, tRNA's accepting all 1m amino acids were demonstrated. "Free" AMV 4S RNA was characterized by very low quantities of glutamate, valine, and tyrosine tRNA's. RNAs accepting all 17 amino acids, with the exception of tyrosine, were shown to be present in the "70S-associated" 4S RNA which dissociates at 60 C. The bulk of the 70S-associated 4S RNA was dissociated at 60 C at low ionic strength with a concomitant conversion of 70S RNA to 35S RNA. The residual associated 4S RNA was dissociated by further heating of the 35S RNA to 80 C; tryptophan tRNA accounted for greater than 90% of the total amino acid accepting activity in this fraction. The results support other studies in suggesting that tryptophan tRNA may serve as a primer for DNA synthesis in AMV, as has been shown in Rous sarcoma virus.
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PMID:tRNA's associated with the 70S RNA of avian myeloblastosis virus. 17 60

The infection process was reproduced in the culture of chick embryonal cells by means of: a) DNA isolated from chick Rous sarcoma (Carr-Zilber strain); b) DNA from blood cells of chicks with myeloblastosis (strain A); c) DNA from Rous virus malignified (Prague strain) rat cells (XC). Antigenic properties of the virus, transfected with DNA from chick Rous sarcoma, would differ from the original parental strain (Carr-Zilber RSV), that evidences the possibility of a partial transfer of genetic information in transfection. A suggestion is made on four presumable variants of oncornaviruses transfection by means of tumor cells DNA.
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PMID:[Transfer of the genetic information of oncornaviruses by means of tumor cell DNA]. 17 3

Immunization of rabbits with a pooled preparation of chromato-graphically purified avian myeloblastosis virus (AMV) group-specific (gs) antigens produced relatively large volumes of antiserum that was as broadly reactive in complement-fixation (CF) tests as antiserum produced in hamsters with tumors induced by Rous sarcoma virus. This alternate procedure should be of value for routine preparation of leukosis virus gs antiserum. Other antisera prepared against disrupted AMV had spurious reactivities that confused CF testing of embryos and tissue extracts. This artifact was attributed to the high affinity of serum albumin for AMV virions and the resultant production of antibodies when plasma-derived AMV was used as immunogen. A high-molecular-weight AMV CF antigen was also found in early fractions eluted from an agarose-gel column.
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PMID:Preparation of antisera to group-specific antigens of avian leukosis-sarcoma viruses: an alternate approach. 19 73

The isoelectric focusing technique in the pH gradients was used for a preparative isolation of proteins from Rous sarcoma virus and avian myeloblastosis virus. The purified major gs protein, p27 (pI = 9.1) and the gP86 (pI = 5.3) were obtained after disruption of virus with 1% non-ionogenic detergent in the presence of 6M urea. The p10, p15, and p19 were present in the same range of pH (pI = 6.8). A strongly basic protein, immunologically active, presumably the p12, was found in the alkaline region of the pH gradient 10.8. These proteins fully retained their immunological activity. On the other hand, in the acidic region of the pH gradient between pH 4 and 5, strong precipitates were regularly found. These precipitates were complexes which were formed by interaction of the acid components of ampholines with the viral proteins during isoelectric focusing. Almost all viral proteins were present, differing only in quantity. The complexes were stabile in 1% non-inogenic detergent and 6M urea. They were dissociated with 1% SDS and 5M urea, and had no immunological activity. The methods of virus disruption and possibilities of formation of the ampholine-viral protein complexes are discussed.
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PMID:Fractionation of proteins from Rous sarcoma virus and avian myeloblastosis virus by isoelectric focusing. 21 31

Addition of purified major glycoprotein from avian myeloblastosis virus to growing or quiescent chicken embryo fibroblasts rapidly stimulates the rate of hexose transport and increases the lactic acid production. These stimulatory effects are dependent on the time of exposure and the dose of viral glycoprotein. In contrast, the glycoprotein only marginally affects hexose transport in chicken cells transformed by Rous sarcoma virus. Some effects of the glycoprotein on serum-starved quiescent cells were similar to those observed upon re-addition of serum; however, the viral glycoprotein did not stimulate DNA synthesis. Quiescent cells stimulated by saturating levels of serum showed little further stimulation of hexose uptake upon exposure to viral glycoprotein for 3 hr. This behavior suggests that the glycoprotein may be acting on a system that is also a target for serum action.
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PMID:Stimulation of sugar uptake and glycolysis in chicken embryo fibroblasts by the major glycoprotein from avian myeloblastosis virus. 22 57

The Rous sarcoma virus (RSV) integrase (IN) and the beta polypeptide (beta) of the reverse transcriptase are posttranslationally modified by phosphorylation on Ser at amino acid position 282 of IN. When IN was immunoprecipitated from RSV (Prague A strain) virions, approximately 30 to 40% of the IN molecules were phosphorylated. When IN was immunoprecipitated from a v-src deletion mutant (delta Mst-A) of RSV or from avian myeloblastosis virus (AMV), the percentage of IN molecules that were phosphorylated was significantly reduced. This reduction in phosphorylation of IN between virions was verified by [35S]Met-[35S]Cys or 32P labeling of IN, followed by immunoprecipitation analysis using antisera directed to the amino or carboxyl terminus of IN. In delta Mst-A or AMV, a nonphosphorylated, slightly truncated (at the carboxyl terminus) polypeptide was the major species of IN. The enhanced phosphorylation of IN does not appear to be a general function of transformed cells, since enhanced phosphorylation was not detected in AMV derived from viremic chickens or from a v-src deletion mutant of RSV propagated in a chemically transformed quail cell line, QT6. From these data, we conclude that v-Src is necessary for efficient phosphorylation of IN and beta.
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PMID:v-Src enhances phosphorylation at Ser-282 of the Rous sarcoma virus integrase. 131 16

To test the effect of long terminal repeat (LTR) regulatory sequences on the transforming capability of the v-myb oncogene from avian myeloblastosis virus (AMV), we have constructed replication-competent avian retroviral vectors with nearly identical structural genes that express v-myb from either AMV or Rous sarcoma virus (RSV) LTRs. After transfection into chicken embryo fibroblasts, virus-containing cell supernatants were used to infect chicken myelomonocytic target cells from preparations of 16-day-old embryonic spleen cells. Both wild-type AMV and the virus expressing v-myb from AMV LTRs (RCAMV-v-myb) were able to transform the splenocyte cultures into a population of immature myelomonocytic cells. The transformed cells expressed the p48v-Myb oncoprotein and formed compact foci when grown in soft agar. In contrast, the virus expressing v-myb from RSV LTRs (RCAS-v-myb) was repeatedly unable to transform the same splenocyte cells, despite being able to infect fibroblasts with high efficiency. This difference in the transforming activities of v-myb-expressing viruses with different LTRs most likely results from the presence of a factor (or factors) within the appropriate myelomonocytic target cell that promotes specific expression from the AMV but not from the RSV LTR.
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PMID:Transformation of chicken myelomonocytic cells by a retrovirus expressing the v-myb oncogene from the long terminal repeats of avian myeloblastosis virus but not Rous sarcoma virus. 132 1

The activity of the avian myeloblastosis virus (AMV) or the human immunodeficiency virus type 1 (HIV-1) protease on peptide substrates which represent cleavage sites found in the gag and gag-pol polyproteins of Rous sarcoma virus (RSV) and HIV-1 has been analyzed. Each protease efficiently processed cleavage site substrates found in their cognate polyprotein precursors. Additionally, in some instances heterologous activity was detected. The catalytic efficiency of the RSV protease on cognate substrates varied by as much as 30-fold. The least efficiently processed substrate, p2-p10, represents the cleavage site between the RSV p2 and p10 proteins. This peptide was inhibitory to the AMV as well as the HIV-1 and HIV-2 protease cleavage of other substrate peptides with Ki values in the 5-20 microM range. Molecular modeling of the RSV protease with the p2-p10 peptide docked in the substrate binding pocket and analysis of a series of single-amino acid-substituted p2-p10 peptide analogues suggested that this peptide is inhibitory because of the potential of a serine residue in the P1' position to interact with one of the catalytic aspartic acid residues. To open the binding pocket and allow rotational freedom for the serine in P1', there is a further requirement for either a glycine or a polar residue in P2' and/or a large amino acid residue in P3'. The amino acid residues in P1-P4 provide interactions for tight binding of the peptide in the substrate binding pocket.
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PMID:Mechanism of inhibition of the retroviral protease by a Rous sarcoma virus peptide substrate representing the cleavage site between the gag p2 and p10 proteins. 133 Oct 99

The structure of the retroviral proteinase from avian myeloblastosis associated virus (MAV) has been determined and refined at 2.2 A resolution. This structure is compared with those of homologous proteinases from Rous sarcoma virus (RSV) and human immunodeficiency type 1 virus (HIV). Through comparison with the structure of a proteinase-inhibitor complex from HIV, a model of a complex between MAV proteinase and a peptide substrate has been generated. Examination of this model suggests structural basis for the diverse specifications of viral proteinases.
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PMID:Structural studies of the retroviral proteinase from avian myeloblastosis associated virus. 133 25

Reverse transcription of the retroviral RNA genome begins with tRNA-primed synthesis of a minus-strand DNA, which subsequently acts as the template for the synthesis of plus-strand DNA. This plus-strand DNA is initiated at a unique location and makes use of a purine-rich RNA oligonucleotide derived by RNase H action on the viral RNA. To determine the variables that are relevant to successful specific initiation of plus-strand DNA synthesis, we have used nucleic acid sequences from the genome of Rous sarcoma virus along with three different sources of RNase H: avian myeloblastosis virus DNA polymerase, murine leukemia virus DNA polymerase, and the RNase H of Escherichia coli. Our findings include evidence that specificity is controlled not only by the nucleic acid sequences but also by the RNase H. For example, while the avian reverse transcriptase efficiently and specifically initiates on the sequences of the avian retrovirus, the murine reverse transcriptase initiates specifically but at a location 4 bases upstream of the correct site.
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PMID:Specificities involved in the initiation of retroviral plus-strand DNA. 168 26


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