The expression of viral and globin genes during differentiation of the friend cell

A complementary DNA probe has been prepared from the Friend murine erythroleukaemia virus complex (FV) released from Friend cells treated with dimethylsulphoxide (DMSO). The complementary DNA (cDNA) forms a hybrid specifically with the viral RNA genome. The availability of this viral probe together with mouse globin cDNA has made it possible to study the expression of both viral and globin genes in the Friend cell during differentiation using molecular hybridisation techniques. These specific probes have been used in an attempt to determine whether any connection exists between expression of Friend virus sequences and erythroid differentiation as measured by globin gene expression. A titration technique has been used to quantitate the levels of Friend viral- and globin-specific sequences in various Friend cell lines which differ in their ability to release Friend virus in response to DMSO although all produce haemoglobin under the same conditions. The results show: (a) that Friend cell lines unable to release virus nevertheless have a large pool of entire virus specific sequences in the polysomes; (b) an increase in virus release induced with DMSO is normally associated with a modest increase in viral sequence in the polysomes; (c) most cell lines show an early accumulation of viral and a later increase in globin mRNA sequences; (d) in an exceptional virus-negative, BUdR-resistant cell clone (B8/3), the accumulation of globin mRNA takes place very rapidly but there is no concomitant increase in viral RNA during differentiation.