Electron microscopy of the nucleic acid of mouse mammary tumor virus.

In vitro production of mouse mammary tumor virus in a mouse mammary tumor ascites line.

An ascites line derived from a spontaneous mouse mammary carcinoma produces, on explantation and cultivation in vitro, large amounts of oncornavirus particles. The biochemical, biophysical, and electron microscopic characteristics of the virions are described. Molecular hybridization and immunological methods identify these virions as mouse mammary tumor virus.

Search for retrovirus-like particles in human breast cancer cells in culture.

We have recently established four new human breast cancer cell lines that were characterized as being of human mammary origin. We examined these cell lines for particles morphologically resembling retroviruses by electron microscopy, for extracellular and intracellular particles containing high-molecular-weight RNA and RNA-directed DNA polymerase by biochemical assays, and for mouse mammary tum...

The nucleic acid of African Horse-Sickness Virus

Correlation between the detection of specific mouse mammary tumor proviral sequences and the presence of pulmonary metastases in mice bearing spontaneous mammary tumors.

Pulmonary metastases in C3H/He mice bearing spontaneous mammary tumors were detected and characterized by histological criteria and immunocytochemical staining for mouse mammary tumor virus antigens. The same lungs containing metastases were also positive when assayed for a specific subset of mouse mammary tumor virus proviral DNA sequences. These sequences, termed tumor-associated sequences, h...

Experimental infection of a cat kidney cell line with the mouse mammary tumor virus.

A cat kidney cell line, CRFK-F2, was successfully inoculated in suspension and in monolayer culture with a purified mouse mammary tumor virus derived from RIII milk. The virus produced by the infected cells was identified by immunogluorescence, electron microscopy, and RNA-directed DNA polymerase assays; it was a B-type virion that did not cross-react with mouse or feline leukemia-sarcoma virus...