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Biomedical subjects

H M Goodman

Publications and source records attributed to H M Goodman.

At least 253 records · Page 14Linked to original sources

Transcription of the Rous sarcoma virus genome in vitro and in vivo.

RNA-directed DNA synthesis by detergent-disrupted virions of Rous sarcoma virus (RSV) initiates by the covalent attachment of pdA to the 3'-terminal rA of a 4S RNA hydrogen-bonded to the 70S RNA template. This 4S "primer" has structural features of tRNA and can be aminoacylated with methionine. Synthesis and integration of provirus DNA can be monitored in both permissive (duck) and nonpermissive (mouse) cells acutely infected with RSV. The results of these studies, as well as data obtained with RSV-infected mammalian cells which have reverted from a transformed to a pheno-typically normal state, indicate that integration of viral genes into the host chromosome is not sufficient cause for transformation. Pertinent features of virus-specific RNA-directed DNA synthesis in vitro and in vivo are reviewed and compared.

Animals↗

Replication and transcription of eukaryotic DNA in Escherichia coli.

Fragments of amplified Xenopus laevis DNA, coding for 18S and 28S ribosomal RNA and generated by EcoRI restriction endonuclease, have been linked in vitro to the bacterial plasmid pSC101; and the recombinant molecular species have been introduced into E. coli by transformation. These recombinant plasmids, containing both eukaryotic and prokaryotic DNA, replicate stably in E. coli. RNA isolated from E. coli minicells harboring the plasmids hybridizes to amplified X. laevis rDNA.

Animals↗

Transcription of DNA from the 70S RNA of Rous sarcoma virus. I. Identification of a specific 4S RNA which serves as primer.

The enzymatic transcription of DNA from the 70S RNA of Rous sarcoma virus (RSV) is initiated on the 3' terminus of a molecule of 4S RNA which is hydrogen bonded to the viral genome. We labeled this primer with radioactive deoxynucleotides, and demonstrated that its release from 70S RNA by thermal denaturation was accompanied by a reduction in the template activity of the viral RNA. Two-dimensional electrophoresis in polyacrylamide gels separated the 4S RNAs associated with the 70S RNA of RSV into approximately eight fractions, each of which appeared to contain a discrete species of tRNA. The RNA in one of these fractions served as the principal primer for initiation of DNA synthesis by both detergent-disrupted virions of RSV and purified RNA-directed DNA polymerase with RSV 70S RNA as template.

Avian Sarcoma Viruses↗

Transcription of DNA from the 70S RNA of Rous sarcoma virus. II. Structure of a 4S RNA primer.

The 70S RNA of Rous sarcoma virus contains 4S RNAs which serve as primers for the initiation of DNA synthesis in vitro by the RNA-directed DNA polymerase of the virus. We purified these primers in three different ways-by isolation of the covalent complex between primer and nascent DNA, by differential melting of the 70S RNA, and by two-dimensional electrophoresis in polyacrylamide gels. The 4S RNAs purified by these procedures were homogeneous and possessed very similar if not identical nucleotide compositions and sequences. The RNAs were approximately 75 nucleotides long, had pG at the 5' terminus and CpCpA(OH) at the 3' terminus, and contained a number of minor nucleotides characteristic of tRNA. In contrast to most tRNA's, the primer lacked rTp and contained Gp (Psip, Psip, Cp) Gp (possibly in place of the characteristic sequence GprTpPsipCpGp). At least 50% of the 4S primers available on 70S RNA were utilized in a standard polymerase reaction in vitro.

Avian Sarcoma Viruses↗

Characterization of the low-molecular-weight RNAs associated with the 70S RNA of Rous sarcoma virus.

Two low-molecular-weight RNAs are associated with the 70S RNA complex of Rous sarcoma virus: a previously described 4S RNA and a newly identified 5S RNA. The 4S RNA constitutes 3 to 4% of the 70S RNA complex or the equivalent of 12 to 20 molecules per 70S RNA. It exhibits a number of structural properties characteristic of transfer RNA as revealed by two-dimensional electrophoresis of oligonucleotides obtained from a T1 ribonuclease digest of the 4S RNA species. The 5S RNA is approximately 120 nucleotides in length, constitutes 1% of the 70S RNA complex or the equivalent of 3 to 4 molecules per molecules of 70S RNA, and is identical in nucleotide composition and structure to 5S RNA from uninfected chicken embryo fibroblasts. Melting studies indicate that the 5S RNA is released from the 70S RNA complex at the same temperature required to dissociate 70S RNA into its constituent 35S subunits. In contrast, greater than 80% of the 4S RNA is released from 70S RNA prior to its conversion into subunits. The possible biological significance of these 70S-associated RNAs is discussed.

Adenosine↗