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Biomedical subjects

D Baltimore

Publications and source records attributed to D Baltimore.

At least 469 records · Page 26Linked to original sources
PubMed1974

Nucleotide sequences of human globin messenger RNA.

Globin messenger RNA, isolated from human peripheral blood reticulocytes, was transcribed into complementary DNA by use of the RNA-dependent DNA polymerase of avian myeloblastosis virus. The complementary DNA was then transcribed into (32)P-labeled complementary RNA by E. coli RNA polymerase in the presence of alpha-(32)P-labeled ribonucleoside triphosphates. The fingerprint pattern obtained from ribonuclease T1 digests of human globin complementary RNA was specific and reproducible. Different patterns were obtained from digests of duck, mouse, and rabbit globin complementary RNA. The fingerprint patterns obtained from digests of purified natural human 10S globin messenger RNA, labeled in vitro with (125)I or with [gamma-(32)P]ATP and polynucleotide kinase, were similar to that of the complementary RNA but contained some additional oligonucleotides. Sufficient nucleotide sequence information has been obtained from about 50% of the intermediate sized oligonucleotides (8-14 base residues long), to make possible examination of correspondence between these nucleotide sequences and globin amino-acid sequences. Approximately 70% of these oligonucleotide sequences can be matched to unique amino-acid sequences in the alpha- or beta-globin chains. The other 30% do not match known amino-acid sequences and presumably correspond to untranslated portions of the mRNA; some of these sequences, however, can be matched to amino-acid sequence in the abnormally long segment of the alpha chain of hemoglobin Constant Spring, which is thought to result from a chain-termination mutation.

Amino Acid Sequence↗
PubMed1974

Requirement of 3'-terminal poly(adenylic acid) for the infectivity of poliovirus RNA.

Ribonuclease H (EC 3.1.4.34) has been used to remove selectively much of the 3'-terminal poly(adenylic acid) [poly(A)] from poliovirus RNA by treating the RNA with the enzyme in the presence of poly(dT). Over 80% of the poly(A) could be removed and the residuum was found as oligo(A) stretches attached to many or all of the viral RNA molecules. Reduction of the size of the poly(A) markedly decreased the specific infectivity of poliovirus RNA, indicating that poly(A) is necessary to the infectivity of the RNA. The virions in plaques deriving from infection with treated RNA have a normal amount and size of poly(A), indicating that mechanisms exist in infected cells to regenerate normal length poly(A) from truncated poly(A).

Adenine Nucleotides↗
PubMed1974

Translation of vesicular stomatitis messenger RNA by extracts from mammalian and plant cells.

RNA was isolated from polyribosomes of vesicular stomatitis virus (VSV)-infected cells and tested for its ability to direct protein synthesis in extracts of animal and plant cells. In cell-free, non-preincubated extracts of rabbit reticulocytes, the 28S VSV RNA stimulated synthesis of a protein the size of the vesicular stomatitis virus L protein whereas the 13 to 15S RNA directed synthesis of the VSV M, N, NS, and possibly G proteins. In wheat germ extracts, 13 to 15S RNA also directed synthesis of the N, NS, M, and possibly G proteins. Analysis of extracts labeled with formyl [(35)S]methionine showed that the 28S RNA directed the initiation of synthesis of one protein, whereas the 13 to 15S RNA directed initiation of at least four proteins. It is concluded that the 28S RNA encodes only the L protein, whereas the 13 to 15S RNA is a mixture of species, presumably monocistronic, which code for the four other known vesicular stomatitis virus proteins.

Animals↗
PubMed1974

Hamster leukemia virus: lack of endogenous DNA synthesis and unique structure of its DNA polymerase.

Infectious hamster leukemia virus (HaLV) contains a DNA polymerase different from those of murine and avian viruses. No endogenous reaction directed by the 60 to 70S RNA of HaLV could be demonstrated in detergenttreated HaLV virions, nor could the purified DNA polymerase copy added viral RNA. The virion RNA could, however, act as template for added avian myeloblastosis virus DNA polymerase and the HaLV DNA polymerase could efficiently utilize homopolymers as templates. The HaLV enzyme was like other reverse transcriptases in that certain ribohomopolymers were much better templates than the homologous deoxyribohomopolymers. No ribonuclease H activity could be shown in the HaLV enzyme, but neither could activity be found in the murine leukemia virus DNA polymerase. The hamster enzyme was unique in that poly(A) .oligo(dT) was a poor template, and globin mRNA primed with oligo(dT) was totally inactive as a template. Its uniqueness was also indicated by its subunit composition; electrophoresis of the HaLV DNA polymerase in sodium dodecyl sulfate-containing polyacrylamide gels revealed equimolar amounts of two polypeptides of molecular weight 68,000 and 53,000. The sedimentation rate of the enzyme in glycerol gradients was consistent with a structure containing one each of the two polypeptides. The enzyme thus appears to be structurally distinct from other known virion DNA polymerases. Its inability to carry out an endogenous reaction in vitro might result from an inability to utilize certain primers.

Animals↗
PubMed1973

Terminal deoxynucleotidyl transferase in a case of childhood acute lymphoblastic leukemia.

Cells from a patient with childhood acute lymphoblastic leukemia contain an apparent DNA polymerase activity that was not found in any other cells except thymus cells. The enzyme has the properties of terminal transferase, an enzyme known to be found in thymocytes. The cells also contain the three major DNA polymerases found in growing cells. The results suggest that these tumor cells arose from a block in the differentiation of thymocytes. Terminal transferase may be a marker for the origin of leukemic cells.

Adenosine Triphosphate↗
PubMed1973

Identification of the vesicular stomatitis virus large protein as a unique viral protein.

Previous studies have noted the existence of a 190,000-dalton vesicular stomatitis virus (VSV) protein called the large (L) protein. To determine whether this protein is a nonspecific aggregate, a precursor to the other VSV proteins, or a unique viral protein, its synthesis relative to the other VSV proteins was studied under conditions of inhibition of initiation of protein synthesis. Also, its tryptic peptides were compared to those of the other VSV proteins. In both cases the results were consistent with the identification of the large protein as a unique viral protein.

Animals↗
PubMed1973

Growth of pseudotypes of vesicular stomatitis virus with N-tropic murine leukemia virus coats in cells resistant to N-tropic viruses.

Formation of pseudotypes between murine RNA tumor viruses and vesicular stomatitis virus (VSV) has been confirmed. Pseudotypes of VSV genomes coated by the surface envelope from an N-tropic tumor virus grew equally well in cells homozygous for either the Fv-1(n) or Fv-1(b) alleles. Therefore, the product of the Fv-1 locus, which restricts growth of murine RNA tumor viruses, must act on an intracellular aspect of tumor virus replication, a step after attachment and penetration.

Animals↗
PubMed1973

Morphogenesis of poliovirus. II. Demonstration of a new intermediate, the proviron.

Poliovirus-infected cells contain a previously unrecognized particle which appears to be an intermediate in virion synthesis and therefore has been named proviron. It sediments at about 125S, contains the three procapsid proteins, VP-0, VP-1, and VP-3, and has 35S viral RNA. It is disrupted both by sodium dodecyl sulfate and EDTA but the RNA resists digestion by ribonuclease. Pulsechase experiments and studies employing the virus-specific inhibitor, guanidine, all indicate that the proviron is formed by combination of newly made RNA with the procapsid. Cleavage of VP-0 to form VP-2 and VP-4 follows formation of the provirion and would be the final step in poliovirus morphogenesis.

Carbon Radioisotopes↗