THE HUMAN PIM-2 PROTOONCOGENE AND ITS TESTICULAR EXPRESSION

In this study we describe the cloning of a human gene, encoding a prot ein that shares 90% identity and 93% similarity at the primary structu re level, with the mouse Pim-2 gene. The gene was designated hPim-2. S tructural features suggest that like the mouse Pim-2, hPim-2 is also a serine threonine kinase. At the RNA level, two hPim-2 transcripts wer e identified. The first, 2.2 kb, is highly expressed in hematopoietic tissues and in leukemic and lymphoma cell lines (K-562, HL-60 and RAJI ). It also shows considerable high levels in testis, small intestine, colon and human colorectal adenocarcinoma cells (SW480). A second tran script, 5.0 kb in size, could be detected only in spleen, thymus, smal l intestine and colon and in the K-562 and RAJI cell lines. In situ hy bridization analysis of biopsies taken from testes of men with complet e or partial spermatogenesis revealed that the gene is expressed in pr imary spermatocytes. In the absence of germ cells, signal could be det ected over specific cells in the well developed interstitial region. T hese results suggest a role for hPim-2 in proliferating cells as well as during meiosis. A possible connection between hPim-2 and apoptosis is discussed. (C) 1998 Elsevier Science B.V. All rights reserved.