Tumor cell heterogeneity.

The paper deals with the analysis of literary data on the tumor cell heterogeneity. Phenotypic, genetic and epigenetic mechanisms of heterogeneity are considered. The heterogeneity of metastasis is considered too.

Differential expression of cellular genes in Rauscher leukaemia.

The methods of hybridization in solution and blot hybridization showed that spleen cells from BALB/c mice contain "silent" genes which can amplify and change their structure after infection by Rauscher leukaemia virus. The "silent" gene product is nuclear 35S RNA detectable by comparative electrophoretic analysis of the heterogeneous nuclear RNA from leukaemic and normal cells. About 7% of this 35S RNA is represented by the virus-specific sequences, but a major part is represented by the cellular sequences.

[Reproduction and assembly of oncoviruses].

Modern investigations of structural and functional organization of oncoviruses are analyzed. The data available in the literature on oncovirus interaction with host cell membrane (adsorption, penetration by endocytosis and fusion, uncoating) as well as the cell and viral receptors are elucidated. The results of the studies on retroviral organization of genome, its integration with cellular genome, transcription and translation are given.

[Activation of cellular genes as affected by Rauscher leukemia virus].

The methods of hybridization in solution and blot hybridization have shown that the BALB/c mice spleen cells contain "silent" genes which can amplificate and change their structure following the infection by the Rauscher leukemia virus (RLV). The product of these gene activation is nuclear 35S RNA detectable by the comparative electrophoretic analysis of heterogeneous nuclear RNA of leukemic and normal cells. The expression of complete copies of 35S RNA was observed in nuclei of RLV-infected cells, while in cytoplasm this RNA is represented by incomplete copies.