Modification of octamer binding transcriptional factor is related to H2B histone gene repression during dimethyl sulfoxide-dependent differentiation of HL-60 cells.

Transcriptional regulation of H2B histone gene during dimethyl sulfoxide (DMSO)-dependent differentiation of HL-60 cells has been investigated using DNase I footprinting and DNA mobility shift assay. The level of histone H2B mRNA showed a slight decline at 2 days and hardly detectable at 4 days after DMSO treatment. H2B histone mRNA was repressed in proportion to the concentration of DMSO. In DNase I footprinting analysis, one nuclear factor (octamer binding transcription factor, OTF) bound at -42 bp (octamer motif, ATTTGCAT) in undifferentiated HL-60 cells. The binding pattern of OTF was unchanged during DMSO-dependent differentiation. One protein complex (OTF) was detected by DNA mobility shift assay in undifferentiated HL-60 cells. The mobility of OTF was partially retarded during DMSO-dependent differentiation and the retardant OTF was not newly synthesized protein. These results suggest that the posttranslational modification of OTF may be responsible for the repression of H2B histone gene during DMSO-dependent differentiation of HL-60 cells.