Identification of novel protein-tyrosine phosphatases in a human leukemia cell line, F-36P

Polymerase chain reaction (PCR) was used to identify protein-tyrosine phosphatases (PTPases) in a human leukemic cell line, F-36P. Degenerate primers deduced from the highly conserved amino acid sequences in the catalytic domain of known PTPases were used for amplification. Among 16 clones sequenced, 13 were identical to known PTPases, whereas the other three clones were disclosed to encode novel PTPases. The expression pattern of one of the three newly identified PTPases, designated as F-36-12, was further analysed. In murine tissues, the F-36-12 message was predominantly expressed in brain, kidney, and intestine, and was weakly expressed in heart and thymus. In human hematopoietic cell lines, the F-36-12 message was preferentially expressed in a promyelocytic leukemic cell line, HL60, and two factor-dependent leukemic cell lines, F-36P and F-36E, that are dependent on granulocyte-macrophage colony-stimulating factor or interleukin-3 and erythropoietin, respectively. The transcript was approximately 8 kb long and the message level in HL60 cells was slightly increased at 24 hours and then slowly declined when treated with dimethyl sulfoxide for granulocyte differentiation, while the message level was rapidly decreased when treated with 12-O-tetradecanoylphorbol 13-acetate for monocyte/macrophage differentiation. These results show that several PTPases including three novel ones are expressed in a human leukemic cell line and that the particular PTPase, F-36-12, might be involved in the differentiation process in HL60 cells.