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)

We have used two methods to detect specific transcription of the chicken alpha 2 (type I) collagen gene in cell-free extracts derived from Rous sarcoma virus-transformed chicken embryo fibroblasts. The first method is a modification of the S1 nuclease mapping procedure which utilizes a DNA probe labeled with 32P at the 5' end of the HindIII linker originally used to clone the collagen promoter region into PBR322. The probe distinguishes newly made, specific RNA from endogenous RNA and nonspecific transcripts. Using this procedure we have found that chicken whole cell extracts support accurate initiation of transcription of the chicken alpha 2 (type I) collagen DNA template. Addition of either creatine phosphate, GTP, or UTP to concentrations of approximately 3 to 5 mM was found to stimulate RNA polymerase II transcription by 5- to 10-fold. The second method employs an avian myeloblastosis virus reverse transcriptase-catalyzed primary extension procedure, rendered in vitro-specific by use of a pBR322 fragment as primer. These two techniques should be useful for analyzing specific transcription in other types of cell-free extracts.
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PMID:Transcription of the chicken alpha 2 (Type I) collagen gene by homologous cell-free extracts. 628 36

We have identified p10 as a fifth gag protein of avian sarcoma and leukemia viruses. Amino-terminal protein sequencing of this polypeptide purified from the Prague C strain of Rous sarcoma virus and from avian myeloblastosis virus implies that it is encoded within a stretch of 64 amino acid residues between p19 and p27 on the gag precursor polypeptide. For p10 from the Prague C strain of Rous sarcoma virus the first 30 residues were found to be identical with the predicted amino acid sequence from the Prague C strain of Rous sarcoma virus DNA sequence, whereas for p10 from avian myeloblastosis virus the protein sequence for the same region showed two amino acid substitutions. Amino acid composition data indicate that there are no gross composition changes beyond the region sequenced. The amino terminus of p10 is located two amino acid residues past the carboxy terminus of p19, whereas its carboxy terminus probably is located immediately adjacent to the first amino acid residue of p27.
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PMID:Amino-terminal amino acid sequence of p10, the fifth major gag polypeptide of avian sarcoma and leukemia viruses. 630 Apr 42

We investigated the interaction of the avian retrovirus pp12 protein with viral RNA to assess its possible role in virion assembly. Using chemical modification techniques, we found that reagents specific for lysine or arginine residues inactivated the RNA-binding capacity of the protein. The binding of pp12 to 60S viral RNA was also strongly affected by pH (pKapp of 5.5); the affinity for viral RNA decreased by as much as 40-fold after protonation of one or more titratable groups on the protein. When the protein was cleaved by cyanogen bromide, each of the two polypeptide products bound to RNA (with low affinity), but pH dependence was lost. Thus, an intact protein was required for this effect. Since histidine and phosphoserine residues have pKa values close to the pKapp of the pp12-RNA interaction, they were studied to determine whether they were involved in this process. Each of the two histidyl residues in pp12 had pKa values of 6.2, as determined by proton nuclear magnetic resonance titrations, values too high to account for the pKapp of binding. The involvement of phosphoserine residues, which have pKa values similar to the pKapp, was investigated by removal of phosphate from pp12. When phosphate groups were chemically or enzymatically removed from the avian myeloblastosis virus, Rous sarcoma virus (Pr-C), and PR-E 95C virus pp12 proteins, the Kapp for binding 60S viral RNA was reduced 100-fold at pH 7.5. Thus, it seems possible that phosphorylation of the pp12 protein could favor viral nucleocapsid formation by increasing its affinity for the viral RNA genome. Dephosphorylation could provide for its release from the viral RNA during reverse transcription after viral infection of cells.
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PMID:Characteristics and regulation of interaction of avian retrovirus pp12 protein with viral RNA. 631 93

Molecular probes for the oncogenes of Rous sarcoma virus (v-src), avian myeloblastosis virus (v-myb), Kirsten murine sarcoma virus (v-Ki-ras), and Harvey murine sarcoma virus (v-Ha-ras) were hybridized to the DNA from mouse-Chinese hamster somatic cell hybrids. The v-src, v-myb, v-Ki-ras, and v-Ha-ras genes each detected one or a few homologous mouse DNA fragments whose segregation was analyzed in cell hybrids. Mouse cellular homologs c-src, c-Ki-ras, c-Ha-ras, and c-myb segregated concordantly with chromosomes 2, 6, 7, and 10, respectively. Comparison with the known locations of human c-src (chromosome 20) and human c-Ha-ras1 (chromosome 11 short arm) suggests that the human and mouse homologs of these two viral oncogenes reside in conserved linkage groups. The c-Ki-ras gene on mouse chromosome 6 might reside also in a conserved linkage group, along with glyceraldehyde-3-phosphate dehydrogenase and triosephosphate isomerase. However, direct confirmation of this suggestion must await a demonstration that c-Ki-ras on mouse chromosome 6 is homologous to c-Ki-ras2 on the short arm of human chromosome 12.
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PMID:Chromosome assignments of four mouse cellular homologs of sarcoma and leukemia virus oncogenes. 632 Jan 93

Rous-associated virus 7 (RAV-7) is a subgroup C avian leukosis virus which does not transform cells in vitro or carry an oncogene. When injected into 1-day-old hatched chicks, RAV-7 causes a low incidence of lymphoid leukosis after a latent period of several months. In contrast, infection of 10-day-old chicken embryos with RAV-7 leads to a disease syndrome characterized by stunting, obesity, atrophy of the bursa and the thymus, high triglyceride and cholesterol levels, reduced thyroxine levels, and increased insulin levels (Carter et al., Infect. Immun. 39:410-422, 1983; J.K. Carter and R.E. Smith, Infect. Immun. 40:795-805, 1983). Histopathological examination of tissues from affected chicks revealed an accumulation of lipid in the liver and an extensive infiltration of the thyroid and pancreas by lymphoblastoid cells. In the present investigation, the subgroup specificity of this syndrome was investigated. Other subgroup C avian leukosis viruses (transformation-defective B77, transformation-defective Prague C strain of Rous sarcoma virus, and RAV-49) caused stunting, infiltration of the thyroid and pancreas, increased liver weights, decreased thyroxine levels, and increased insulin levels, but they did not cause a uniform, profound increase in triglyceride and cholesterol levels. Avian leukosis viruses of subgroup A [myeloblastosis-associated virus 1 causing osteopetrosis [MAV-1(O)] and RAV-1], subgroup B [MAV-2(O), MAV-2 causing nephroblastoma [MAV-2(N)], and RAV-2], subgroup D (RAV-50), and subgroup F (ring-necked pheasant virus and RAV-61) did not cause a syndrome identical to that induced by RAV-7. All of the viruses examined induced some stunting and a reduction in thyroxine levels which correlated with the stunting. The two subgroup F viruses caused an infiltration of the thyroid which may have been secondary to severe lung involvement. We conclude that the RAV-7 syndrome is unique, particularly in the induction of a hyperlipidemia.
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PMID:Specificity of avian leukosis virus-induced hyperlipidemia. 632 32

The CA (capsid) protein of avian sarcoma and leukemia viruses occurs in multiple species. Only one form has been previously characterized biochemically. We have now determined that the mature CA protein of avian sarcoma and leukemia viruses exists as three species with different C termini, ending in amino acid residues A-476, A-478, and M-479 of the Gag precursor, respectively. These structures were deduced from a combination of cyanogen bromide peptide mapping, sequence analysis of tryptic peptides, and electrospray mass spectrometry. The three forms of CA were detected in the same ratios in Rous sarcoma virus and avian myeloblastosis virus and therefore are likely to represent a common feature of members of this genus of avian retroviruses. The only previously reported CA species, CAM-479, accounts for only about 36% of the total CA protein, while CAA-476 and CAA-478 account for 55 and 9%, respectively. From the analysis of peptides cleaved in vitro by PR, the viral protease, we infer that the cleavage site between A-476 and A-477 not only is recognized by PR but is the preferred site. We were unable to determine if A-478/A-479 is a cleavage site for PR or alternatively if CAA-478 results from further processing of CAM-479 by a carboxypeptidase. To study the biological significance of residues A-477 to M-479, we constructed genetically altered viruses in which deletions removed either residues 477 to 479 or 477 to 488. The resulting virus particles appeared to assembly with normal efficiencies, but the latter mutant showed slowed proteolytic processing. Neither of the mutants was infectious.
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PMID:Differential proteolytic processing leads to multiple forms of the CA protein in avian sarcoma and leukemia viruses. 766 44

The avian myeloblastosis virus (AMV) induces acute monoblastic leukemia in chickens and transforms only myelomonocytic cells in vitro. The long terminal repeat (LTR) regulatory region of AMV is unique among the known classes of avian retrovirus LTRs. We demonstrate that the substitution of the AMV LTRs by Rous sarcoma virus LTRs did not alter the cell type specificity or the transforming ability of the virus.
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PMID:Transformation of myelomonocytic cells by the avian myeloblastosis virus is determined by the v-myb oncogene, not by the unique long terminal repeats of the virus. 813 52

A steady state kinetic analysis of the avian myeloblastosis virus/Rous sarcoma virus (AMV/RSV) and human immunodeficiency virus Type 1 (HIV-1) retroviral proteases (PRs) was carried out using a series of 40 peptide substrates that are derivatives of the AMV/RSV nucleocapsid-PR cleavage site. These peptides contain single amino acid substitutions in each of the seven positions of the minimum length substrate required by the PR for specific and efficient cleavage. These peptide substrates are distinguished by the individual enzyme subsites of the AMV/RSV and HIV-1 PRs. The molecular basis for similarities and differences of the individual subsites for both proteases is discussed using steady state kinetic data and modeling based on crystal structures.
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PMID:Comparison of the substrate-binding pockets of the Rous sarcoma virus and human immunodeficiency virus type 1 proteases. 838 61

The U3 and U5 termini of linear retrovirus DNA contain imperfect inverted repeats that are necessary for the concerted insertion of the termini into the host chromosome by viral integrase. Avian myeloblastosis virus integrase can efficiently insert the termini of retrovirus-like DNA donor substrates (480 base pairs) by a concerted mechanism (full-site reaction) into circular target DNA in vitro. The specific activities of virion-derived avian myeloblastosis virus integrase and bacterial recombinant Rous sarcoma virus (Prague A strain) integrase (approximately 50 nM or less) appear similar upon catalyzing the full-site reaction with 3'-OH recessed wild type or mutant donor substrates. We examined the role of the three nonsymmetrical nucleotides located at the 5th, 8th, and 12th positions in the U3 and U5 15-base pair inverted repeats for their ability to modify the full-site and simultaneously, the half-site strand transfer reactions. Our data suggest that the nucleotide at the 5th position appears to be responsible for the 3-5-fold preference for wild type U3 ends over wild type U5 ends by integrase for concerted integration. Additional mutations at the 5th or 6th position, or both, of U3 or U5 termini significantly increased (approximately 3 fold) the full-site reactions of mutant donors over wild type donors.
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PMID:Avian retrovirus U3 and U5 DNA inverted repeats. Role Of nonsymmetrical nucleotides in promoting full-site integration by purified virion and bacterial recombinant integrases. 929 44

Recombinant Rous sarcoma virus integrase cloned from the Prague A (PrA) virus strain was expressed in Escherichia coli. Here we report the detailed purification procedure resulting in an apparently homogeneous integrase. Recombinant PrA integrase was compared at both the protein structural and the catalytic levels to avian myeloblastosis virus integrase purified from virions. Both proteins exist minimally in a dimeric state at low nanomolar concentrations as analyzed by glycerol gradient sedimentation and protein crosslinking studies. Likewise, both proteins have similar specific activities for full-site (concerted integration reaction) and half-site strand transfer activities using linear 480-bp retrovirus-like donor substrates that contain wild-type or mutant termini. They respond similarly to high NaCl concentrations ( approximately 350 mM) as well as aprotic solvents for efficient full-site strand transfer. The data suggest that recombinant integrase proteins with physical and catalytic properties similar to the virion counterpart can be purified using these techniques and will faithfully and efficiently promote the full-site integration reaction in vitro.
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PMID:Purification of recombinant Rous sarcoma virus integrase possessing physical and catalytic properties similar to virion-derived integrase. 979 Aug 78


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