Fig. 7. Expression of mi by immunofluorescence in MC29-infected QNR cells. A, subcellular localization of Mi protein was assayed by indirect immunofluorescence with serum MiC on fixed MC29-QNR cells grown for 24 h onto 16 mm glass coverslips. a, MC29-QNR after three passages (P3). b, MC29-QNR after five passages (P5). c, MC29-QNR after seven passages (P7). d, control QNR cells infected by the helper virus after only five passages (P5). Anti-Mi-immunoreactive proteins were detected with FITC-labeled swine antirabbit immunoglobulin secondary reagent. Note that, in control QNR P5, the nuclei were not labeled. B, percentage of MiC-labeled nuclei in the different MC29-QNR. At least 500 cells were scored, except for P1 and P3, in which all of the positive cells on the coverslip were counted. Except for the P3 culture, the coverslips were covered by an equivalent number of cells. Note that the culture appeared fully transformed as early as P1.