The expression of neomycin phosphotransferase in human promyelocytic leukemia cells (HL60) delays their differentiation.

In a series of experiments investigating the differentiation of human promyelocytic leukemia cells (HL60) in the presence of chemical inducers, we have transduced the bacterial neomycin-phosphotransferase (NPT) gene into the HL60 genome. We show here, that HL60 cells expressing the NPT gene under the control of different transcriptional promoters differentiate significantly slower than the parental HL60 cells. Competition experiments involving the use of excess amounts of specific NPT substrate (i.e. G418) revealed that the delay in the differentiation response of neo-resistant HL60 cells results from the action of the neomycin-phosphotransferase protein. We conclude that the activity of the NPT gene may prove a useful tool in elucidating the control of differentiation in HL60 cells.