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. In order to study the expression of the sequences homologous to 35S RNA in leukaemic and normal cells, hybridization in solution was used. Expression of the complete copies of 35S RNA was observed in nuclei of virus-infected cells, whereas this RNA in the cytoplasm is represented by the incomplete copies. The expression of the sequences homologous to this 35S RNA in normal mouse spleen cells was not revealed.