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Biomedical subjects

R Soeiro

Publications and source records attributed to R Soeiro.

At least 55 records · Page 3Linked to original sources
PubMed1976

Host restriction of Friend Leukemia virus coat protein synthesis.

Fv-1 gene-mediated host restriction of Friend leukemia virus replication was investigated in terms of coat protein synthesis. By using the assay of pseudotype formation with vesicular stomatitis virus. it was shown that under restricting growth conditions the availablity of leukemia virus coat protein for pseudotype formation was decreased. These studies appear to eliminate a pure assembly defect as the mechanism of Fv-1 host restriction.

Cell Line↗
PubMed1976

Fate of input oncornavirion RNA--biological studies.

The fate of input Friend leukemia virus RNA was studied using labeled input virus. The appearance of nuclear RNA-DNA hybrid molecules and the apparent integration of input virion RNA with host cell DNA was studied using a series of inhibitors of DNA or protein synthesis, cell growth conditions, and an intercalating agent. Under all these conditions of infection, little to no viral-specific RNA-DNA hybrid molecules were formed. These data demonstrate that the formation of such RNA-DNA hybrid structures requires conditions of infection that allow provirus synthesis and integration. Furthermore, they suggest that at least a fraction of input virion RNA may transiently become integrated with host cell DNA.

Adsorption↗
PubMed1973

Purification of oncornaviruses by agglutination with concanacalin A (murine leukemia virus-phytohemagglutinin-friend virus).

Concanavalin A (Con A) has been used to rapidly and selectively agglutinate murine and avian oncornavirions from culture medium or plasma. The agglutinated virus was concentrated rapidly and gently by low-speed centrifugation and solubilization with alpha-methyl mannoside. Infectious virus was purified 2.3 times with respect to nucleic-acid content, and more than 60% of its infectivity was recovered. Infectious particles of densities 1.18 and 1.16 g/cm(3) were found in mouse cells infected with Friend virus. Con A reacted only with particles of density 1.16 g/cm(3), indicating heterogeneity with respect to carbohydrate content or structure as well as buoyant density. Electron microscopy of virus agglutinated with Con A showed a zone of Con A-glycoprotein complexes averaging 12-15 nm in thickness.

Agglutination↗
PubMed1973

Host restriction of Friend leukemia virus. Role of the viral outer coat.

Host restriction of oncogenesis of RNA tumor viruses in vivo is associated with several gene loci. One of these genes, the Fv-1 locus in mice, is expressed in vitro and may be studied in mouse-embryo cultures that are restrictive or permissive for replication of Friend leukemia virus. Two strains of Friend leukemia virus, N-or B-tropic, show reciprocal ability to replicate successfully in either NIH Swiss (N-type) or BALB/c (B-type) cells that differ at the Fv-1 locus. These two strains of virus and two cell lines form a system to measure host restriction in vitro. Measurement of adsorption of Friend leukemia virus to permissive or restrictive cells reveals no difference in rate or total amount of virus bound. Furthermore, studies with virions of vesicular stomatitis virus phenotypically mixed within an envelope containing Friend leukemia virus protein show no differences in penetration or replication of vesicular stomatitis virus. These results strongly suggest that host restriction of Friend leukemia virus is due to an intracellular event in the viral replication cycle.

Animals↗
PubMed1970

A comparison between heterogeneous nuclear RNA and polysomal messenger RNA in HeLa cells by RNA-DNA hybridization.

Heterogeneous nuclear RNA (HnRNA) and mRNA from cytoplasmic polyribosomes of HeLa cells have been compared by RNA-DNA hybridization tests. 1 microg of HeLa cell DNA binds 0.05-0.10 microg of either HnRNA or mRNA. In addition, HeLa DNA that is preexposed to unlabeled HnRNA was found to have a reduced capacity to bind either HnRNA or mRNA. The results are compatible with considerable sequence similarity in the two types of RNA but, as is discussed, firm conclusions are precluded by imperfections of the hybridization reaction as presently employed.

Cell Nucleus↗
PubMed1968

The turnover of nuclear DNA-like RNA in HeLa cells.

The subcellular distribution of various types of RNA in HeLa cells is described. In addition, the relative rate of synthesis of the major classes of nuclear RNA has been determined. From these experiments it can be deduced that the heterogeneous nuclear RNA fraction is rapidly synthesized and degraded within the cell nucleus.

Carbon Isotopes↗