Detection of genes coding for human differentiation markers by their transient expression after DNA transfer.

We have developed an assay for specific genes in DNA based on transient expression. DNA prepared from patients with acute myeloblastic or acute lymphoblastic leukemia or from the continuous leukemic cell line HL60 was transferred to LTA cells; 48-72 hr later, these recipients expressed hemopoietic differentiation markers as detected by monoclonal antibodies against My-1 (granulocyte specific) and OK-T3 (T-cell specific) using immunofluorescence. The efficiency of transfer was dose and time dependent. We found that genes not expressed in the original cells were expressed after transfer by using this assay. Restriction enzyme analysis showed that My-1 was not expressed with DNA that had been incubated before transfer with either HindIII or Sal I but was present after digestion with either EcoRI or BamHI; after digestion of DNA with the same enzymes, OK-T3 expression was observed only in the HindIII-treated DNA. These studies indicate that DNA was transferred; this approach may provide an efficient method for detecting the activity of specific genes in the absence of selection.