MINUTE VIRUS OF MICE INFECTION MODIFIES CELLULAR TRANSCRIPTION ELONGATION

Our previous observations indicated that upon infection with minute vi rus of mice (MVM), Ehrlich ascites cells lose a transcription elongati on activity which is essential for the readthrough of the MVM attenuat or. This was monitored by the ability of extracts from uninfected but not from infected cells to support readthrough of the P4 attenuator wh en added to partially purified transcription elongation complexes. We have investigated the nature of this change in transcription elongatio n following MVM infection. In this communication, we show that infecti on of Ehrlich ascites cells with MVM leads to a general shift in the l ength of nascent mRNA synthesized in isolated nuclei and separated by sucrose gradients. Furthermore, infection leads to attenuation of tran scription of the cellular gene c-fos but not c-myc. We show biochemica l evidence to support a model by which, following MVM infection, there is a functional reduction in the activity of a TFIIS-like general tra nscriptional elongation activity.