The dimethyl sulfoxide (Me2SO)-mediated induction of hemoglobin synthesis in Friend leukemia cells (a murine erythroblastoid cell line) is coupled with the number of cell replications occurring in the presence of inducer. Varying concentrations of proflavine increase the generation time of these cells from 24 hours to over 50 hours, and in each case the induction of hemoglobin synthesis follows the completion of two cell doublings. Once the induction is initiated, the rate of hemoglobin accumulation is not affected by proflavine. These data indicate that proflavine does not affect the transcription or translation of globin mRNA and that the delay in induction of hemoglobin synthesis is due to its effect on the rate of cellular replication. In experiments using high concentrations of thymidine to block replication, hemoglobin accumulation is prevented only if the cells are blocked prior to 36 hours after Me2SO addition. If the cells have completed two generations in the presence of Me2SO, there is no effect upon their ability to synthesize hemoglobin even though their growth is arrested. Thus, the inhibition of hemoglobin synthesis by proflavine is not merely the result of a toxic effect on newly subcultured cells but is due to its effect on cellular replication. These experiments confirm that, after addition of Me2SO, Friend leukemia cells require more than one complete cell cycle in order to synthesize hemoglobin.
|Original language||English (US)|
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jun 7 1976|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology