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

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Query: EC:3.1.27.3 (RNase T1)
1,228 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Based on the observation that in vitro transcription of Rous sarcoma virus (RSV) RNA by avian myeloblastosis virus DNA polymerase renders the RNA PROGRESSIVELY MORE SENSITIVE TO Escherichia coli RNase H digestion, a new procedure for the in situ analysis of this process has been developed. In vitro transcription products of 32P-labeled RSV RNA are first treated with RNase H, the resistant fraction is then digested to completion with RNase T1, and the oligonucleotides are analyzed by a fingerprint technique. By using the established order of these oligonucleotides along the RNA molecule, a comparison of the yields of each oligonucleotide, before and after transcription, allows qualitative and quantitative in situ analyses of the transcription process. Using this new procedure, we find that upon transcription of purified RSV RNA, DNA synthesis occurs mainly at three sites, one near the 5' end and two near the center of the subunit RNA molecule, and that most of these RNA molecules are competent templates for limited transcription at these specific sites. We also show that purified RSV 70S RNA contains a low-molecular-weight DNA hybridized to a nucleotide sequence near the center of the subunit molecule. Furthermore , we find that the low-molecular-weight nucleic acid fraction extracted from purified RSV virions contains DNA that can hybridize to RSV 70S RNA and that the virion DNA in such hybrids can function as a primer for an extensive in vitro reverse transcription.
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PMID:New procedure for the direct analysis of in vitro reverse transcription of Rous sarcoma virus RNA. 6 18

The RNA of a replication-defective (rd) mutant, isolated from stocks of nondefective (nd) Schmidt-Ruppin Rous sarcoma virus of subgroup A (SR-A) and termed SR-N8, was compared to the RNAs of SR-A, of a transformation-defective derivative of SR-A (td SR-A) and of rd Bryan Rous sarcoma virus, RSV (minus). The molecular mass of the 30-40S species of SR-N8 RNA was estimated to be 21% (congruent to 7.5 to 8 times 10-5 daltons) smaller than that of SR-A by (i) electrophoresis in polyacrylamide gels and (ii) analyses of RNA complexity based on RNase T1-resistant oligonucleotides. ST-N8 shares probably all (=14) of its large RNase T1-resistant oligonucleotides with the RNA of SR-A as judged from the chromatographic distribution and the RNase A-resistant fragments obtained from RNase T1-resistant oligonucleotides. However, SR-N8 RNA lacked six large oligonucleotides which were present in the RNAs of SR-A and td SR-A. Conversely, the RNAs of SR-A, and of SR-N8 contained two oligonucleotides not found in td SR-A. The RNA of SR-N8 was found to differ from that of RSV (minus) in its electrophoretic mobility and its fingerprint pattern. It is concluded that the RNA of SR-N8 was generated by a deletion of SR-A. The extent of this deletion is compatible with the notion that the genetic information for the large viral envelope glycoprotein (molecular mass = 70,000-85,000 daltons) has been lost from the RNA of SR-A to yield SR-N8 RNA. From a comparison of td and rd deletion mutants, it appears that loss of different functions corresponds to the absence of different oligonucleotides in their RNA.
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PMID:RNA of replication-defective strains of Rous sarcoma virus. 16 14

The large RNase T1-resistant oligonucleotides of the nondefective (nd) Rous sarcoma virus (RSV): Prague RSV of subgroup B (PR-B), PR-C and B77 of subgroup C; of their transformation-defective (td0 deletion mutants: td PR-B, td PR-C, and td B77; and of replication-defective (rd) RSV(-) were completely or partially mapped on the 30 to 40S viral RNAs. The location of a given oligonucleotide relative to the poly(A) terminus of the viral RNAs was directly deduced from the smallest size of the poly(A)-tagged RNA fragment from which it could be isolated. Identification of distinct oligonucleotides was based on their location in the electrophoretic/chromatographic fingerprint pattern and on analysis of their RNase A-resistant fragments. The following results were obtained. (i) The number of large oligonucleotides per poly(A)-tagged ffagment increased with increasing size of the fragment. This implies that the genetic map is linear and that a given RNase T1-resistant oligonucleotides has, relative to the poly(A) end, the same location on all 30 to 40S RNA subunits of a given 60 to 70S viral RNA complex, (ii) Three sarcoma-specific oligonucleotides were identified in the RNAs of Pr-B, PR-C and B77 by comparison with the RNAs of the corresponding td viruses...
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PMID:Mapping RNase T1-resistant oligonucleotides of avian tumor virus RNAs: sarcoma-specific oligonucleotides are near the poly(A) end and oligonucleotides common to sarcoma and transformation-defective viruses are at the poly(A) end. 17 Apr 11

The genetic complexities of several ribodeoxyviruses were measured by quantitative analysis of unique RNase T1-resistant oligonucleotides from 60-70S viral RNAs. Moloney murine leukemia virus was found to have an RNA complexity of 3.5 x 10(6) daltons, whereas Moloney murine sarcoma virus had a significantly smaller genome size of 2.3 x 10(6). Reticuleondotheliosis and visna virus RNAs had complexities of 3.9 x 10(6), respectively. Analysis of RNase A-resistant oligonucleotides of Rous sarcoma virus RNA gave a complexity of 3.6 x 10(6), similar to that previously obtained with RNase T1-resistant oligonucleotides. Since each of these viruses was found to have a unique sequence genomic complexity near the molecular weight of a single 30-40S viral RNA subunit, it was concluded that ribodeoxyvirus genomes are at least largely polyploid.
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PMID:Genomic complexities of murine leukemia and sarcoma, reticuloendotheliosis, and visna viruses. 17 29

The cell-free synthesis of three major proteins from virion RNA of nondefective Rous sarcoma virus (RSV), but not from RNA of transformation-defective deletion mutants, has been observed. The apparent molecular weights of these transformation-specific proteins are approximately 60,000 (60K), 25K, and 17K. Tryptic maps of methionine-containing peptides revealed the 17K, 25K, and 60K proteins to be overlapping in sequence. However, only partial homology was observed between the 17K, 25K and 60K proteins synthesized from Schmidt-Ruppin strain, subgroup D, RSV RNA and those synthesized from Prague strain, subgroup B, RSV, RNA. About half of the methionine peptides in the Schmidt-Ruppin strain, subgroup D, 60K protein were shared with the Prague strain, subgroup D, 60K protein, and the rest were distinct to each. The virion RNAs coding for the 60K, 25K, and 17K proteins were found to be polyadenylated and to sediment with maximal mRNA activity at about 23, 19 to 20, and 18S, respectively. In addition, transformation-specific proteins with molecular weights of 39K and 33K were observed by in vitro synthesis. These proteins are also related to the 60K, 25K, and 17K proteins and were synthesized from polyadenylated RSV RNA of approximately 21 to 22S. RNase T1-resistant oligonucleotides were analyzed in parallel, and the src-specific oligonucleotides were found to be first present in equimolar amounts in those gradient fractions sedimenting at 21 to 22S. Our data suggest that synthesis of the 60K protein is initiated near the 5' terminus of the src gene, whereas the 39K, 33K, 25K, and 17K proteins are initiated internally in the src gene. All of these proteins appear to be initiated independently, but they may have a common termination site.
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PMID:Characterization of Rous sarcoma virus src gene products synthesized in vitro. 21 78

An intracellular assay for viral envelope glycoprotein (env) messenger was employed to analyze the RNA from virus particles of Rous-associated virus type 2. For this assay RNA was microinjected into cells infected by the env-deficient Bryan strain of Rous sarcoma virus [RSV(-) cells]. Only when the injected RNA could be translated by the recipient cells to produce viral envelope glycoprotein was the env deficiency of the RSV(-) cells complemented, enabling them to release focus-forming virus. RNA in a 21S size fraction from the Rous-associated virus particle promoted the release of numerous focus-forming virus from RSV(-) cells, whereas the major 35S virion RNA species was inactive. The env messenger activity sedimented as a sharp peak with high specific activity. RNase T1-generated fragments of virion 35S RNA were unable to promote the release of infectious virus from RSV(-) cells. Consequently, the active molecule was most likely to be env messenger which had been encapsulated by the virus particle from the cytoplasm of infected cells. Approximately 95% of the env messenger within the virion was associated with the virion high-molecular-weight RNA complex. The temperature required to dissociate env messenger from the high-molecular-weight complex was indistinguishable from the temperature required to disrupt the complex itself. Virion high-molecular-weight RNA that was associated with env messenger sedimented slightly more rapidly than the bulk virion RNA; this was the strongest evidence that the 21S messenger had been encapsulated directly from the infected cells. These data are considered along with a related observation [concerning the prolonged expression of env messenger after injection into RSV(-) cells] to raise the possibility that virus-encapsulated env messenger can become expressed within subsequently infected cells.
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PMID:Messenger activity of virion RNA for avian leukosis viral envelope glycoprotein. 22 82

The use of mercurated "strong stop" complementary DNA (complementary to the 5'-terminal 101 nucleotides of Rous sarcoma virus RNA) in the isolation of virus-specific RNA from infected chicken embryo fibroblasts is described. Strong stop Rous sarcoma virus complementary DNA was mercurated chemically, and, as a result of the low complexity of this DNA, short hybridization times (up to 15 min) and heating in the absence of formamide were found to be adequate conditions for the isolation of virus-specific RNA. The purity of the isolated RNA was demonstrated by analysis of labeled RNase T1-resistant oligonucleotides by two-dimensional polyacrylamide gel electrophoresis. The isolated RNA could be translated in the in vitro protein synthesis system derived from rabbit reticulocytes, and an analysis of polypeptides programmed by isolated RNA before and after immunoprecipitation further demonstrated both the purity of the isolated mRNA and the quantitative nature of the isolation procedure.
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PMID:New procedure for isolation of Rous sarcoma virus-specific RNA from infected cells. 22 62

Tumors were produced in quails about 2 months after injection with a transformation-defective mutant of the Schmidt-Ruppin strain of Rous sarcoma virus, subgroup A (SR-A), that retains a small portion of the src gene. Sarcoma viruses were isolated from each of five such tumors. A transformation-defective mutant which has a nearly complete deletion of the src gene was unable to induce tumors. The avian sarcoma viruses recovered from quail tumors (rASV-Q) had biological properties similar to those of the avian sarcoma viruses previously acquired from chicken tumors (rASV-C); these chicken tumors had been induced by the same transformation-defective mutants. Both rASV-Q and rASV-C transformed cells in culture with similar focus morphology and produced tumors within 7 to 14 days after injection into chickens or quails. The size of rASV-Q genomic RNA was indistinguishable from that of SR-A by polyacrylamide gel electrophoresis. The sequences of rASV-Q RNA genomes were analyzed and compared with those of the parental transformation-defective virus, SR-A and of rASV-C by RNase T1 fingerprinting and oligonucleotide mapping. We found that the src sequences of all five isolates of rASV-Q were identical to each other but different from those of SR-A and rASV-C. Of 13 oligonucleotides of rASV-Q identified as src specific, two were not found in either SR-A or rASV-C RNA. Furthermore, some oligonucleotides present in SR-A or rASV-C or both were absent in rASV-Q. No differences were found for the sequences outside the src region in any of the viruses examined. In addition, rASV-Q-infected cells possessed a 60,000-dalton protein specifically precipitable by rabbit serum raised against SR-D-induced tumors. The facts that the src sequences are essentially the same for rASV's recovered from one animal species and different for rASV's obtained from different species provide conclusive evidence that cellular sequences of normal birds were inserted into the viral genome and supplied to the resulting recombinant viruses genetic information for cell transformation.
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PMID:Analysis of the src gene of sarcoma viruses generated by recombination between transformation-defective mutants and quail cellular sequences. 22 78

The RNA species of the defective avian acute leukemia virus MC29 and of the defective avian carcinoma virus MH2 and of their helper viruses were analyzed using gel electrophoresis, fingerprinting of RNase T1-resistant oligonucleotides, RNA-cDNA hybridization and in vitro translation. A28S RNA species, of 5700 nucleotides, was identified as MC29- or MH2-specific. MC29 RNA shared 4 out of about 17 and MH2 RNA at least 1 out of 16 T1-oligonucleotides with several other avain tumor virus RNAs. In addition MC29 and MH2 RNAs shared 2 oligonucleotides which were not found in any other viral RNA tested. 60% of each 28S RNA could be hybridized by DNA complementary to other avian tumor virus RNAs (group-specific) but 40% could only be hybridized by homologous cDNA (specific). Src gene-related sequences of Rous sarcoma virus were not found in MC29 or MH2 RNA. The specific and group-specific sequences of MC29, defined in terms of their T1-oligonucleotides, were located on a map of all T1-oligonucleotides of viral RNA. Specific sequences mapped between 0,4 and 0,7 map units from the 3'poly(A) end and group-specific sequences mapped between 0 and 0,4 and 0,7 and 1 map units. The MC29-specific RNA segment was represented by 6 oligonucleotides, two of which were those shared only by MC29 and MH2 RNAs. In vitro translation of MC29 RNA generated a major 120 000 dalton protein and minor 56 000 and 37 000 dalton proteins. The 120 000 dalton protein shared sequences with the proteins of the avian tumor viral gag gene, which maps at the 5' end of independently replicating viruses. Since a gag gene-related oligonucleotide was also found near the 5' end of MC29 RNA, we propose that the 120 000 MC29 protein was translated from the 5' 60% of MC29 RNA. It would then include sequences of the defective gag gene as well as MC29-specific sequences. Since both MC29 and MH2 lack the src (sarcoma) gene of Rous sarcoma virusk it is concluded that they contain a distinct class of transforming (onc) genes. We propose that the specific sequences of MC29 and MH2 represent all, or part of, their onc genes because the onc genes of MC29 and MH2 are specific and represent the only known genetic function of these viruses. If this proposal is correct, the onc genes of MC29 and MH2 would be related, because the specific RNA sequence of MC29 shares 2 of 6 oligonucleotides with MH2. It would also follow that the 120 000 dalton MC29 protein is a probable onc gene product, because it is translated from MC29-specific (and group-specific) sequences and because both MC29- and MH2-transformed cells contain specific 120 000 and 100 000 dalton proteins, respectively.
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PMID:Anatomy of the RNA and gene products of MC29 and MH2, two defective avian tumor viruses causing acute leukemia and carcinoma: evidence for a new class of transforming genes. 23 56

The genome of the defective, murine spleen focus-forming Friend virus (SFFV) was identified as a 50S RNA complex consisting of 32S RNA monomers. Electrophoretic mobility and the molecular weights of unique RNase T1-resistant oligonucleotides (T1-oligonucleotides) indicated that the 32S RNA had a complexity of about 7.4 kilobases. Hybridization with DNA complementary to Friend murine leukemia virus (Fr-MLV) has distinguished two sets of nucleotide sequences in 32S SFFV RNA, 74% which were Fr-MLV related and 26% which were SFFV specific. By the same method, SFFV RNA was 48% related to Moloney MLV. We have resolved 23 large T1-oligonucleotides of SFFV RNA and 43 of Fr-MLV RNA. On the basis of the relationship between SFFV and Fr-MLV RNAs, the 23 SFFV oligonucleotides fell into four classes: (i) seven which had homologous equivalents in Fr-MLV RNA; (ii) six more which could be isolated from SFFV RNA-Fr-MLV cDNA hybrids treated with RNases A and T1; (iii) eight more which were isolated from hybrids treated with RNases A and T1; and (iv) two which did not have Fr-MLV-related counterparts. Surprisingly, the two class iv oligonucleotides had homologous counterparts in the RNA of six amphotropic MLV's including mink cell focus-forming and HIX-MLVs analyzed previously. The map locations of the 23 SFFV T1-oligonucleotides relative to the 3' polyadenylic acid coordinate of SFFV RNA were deduced from the size of the smallest polyadenylic acid-tagged RNA fragment from which a given oligonucleotide was isolated. The resulting oligonucleotide map could be divided roughly into three segments: two terminal segments which are mosaics of oligonucleotides of classes i, ii, and iii and an internal segment between 2 and 2.5 kilobases from the 3' end containing the two oligonucleotides shared with amphotropic MLVs. Since SFFV RNA consists predominantly of sequence elements related to ecotropic and amphotropic helper-independent MLVs, it would appear that the transforming gene of SFFV is not a major specific sequence unrelated to genes of helper viruses, as is the case with Rous sarcoma and probably withe other defective sarcoma and acute leukemia viruses.
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PMID:Spleen focus-forming Friend virus: identification of genomic RNA and its relationship to helper virus RNA. 50 95


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