Characterization of the human PIM-1 gene: a putative proto-oncogene coding for a tissue specific member of the protein kinase family.

The mouse PIM-1 gene is involved in the pathogenesis of virally-induced mouse lymphomas. We have cloned and analyzed the human homologue of the mouse PIM-1 gene to investigate its role in human lymphoma and leukemia. Overlapping cDNA clones from a K562 (human erythroleukemia cell line) library were isolated and sequenced. The deduced amino acid sequence showed significant homology to a number of the protein kinases but did not have a transmembrane region. Genomic clones from the 380 cell line (human B cell leukemia) were analyzed. The PIM-1 transcript was found to derive from 5 Kb of genomic DNA. Six exons and five introns were identified. The promoter region has no TATA or CAAT boxes, but did have multiple potential Sp1 binding sites (CCGCCC). Studies of expression of this gene using Northern blots of human cell lines showed it to be transcribed primarily in B lymphoid and myeloid cell lines. The characterization of the human PIM-1 gene will allow the definition of its role in hemopoietic malignancies and in hematolymphoid differentiation.