Expression of leukocyte alkaline phosphatase gene in normal and leukemic cells: Regulation of the transcript by granulocyte colony-stimulating factor

Alessandro Rambaldi, Mineko Terao, Stefania Bettoni, Maria Laura Tini, Renato Bassan, Tiziano Barbui, Enrico Garattini

Research output: Contribution to journalArticle


The levels of leukocyte alkaline phosphatase (LAP) messenger RNA (mRNA) are evaluated in B and T lymphocytes, monocytes, and polymorphonuclear cells (PMNs), and this transcript is found to be present only in PMNs. Precursors of the myelomonocytic pathway, represented by leukemic cells isolated from several cases of chronic myelogenous leukemia (CML) in its stable and blastic phase and acute myelogenous leukemia (AML), are devoid of LAP transcript. These data support the notion that LAP is a marker of the granulocyte terminal differentiation. Despite the absence of LAP mRNA in both the myeloid and the lymphoid precursors, nuclear run-on experiments show constitutive transcription of the LAP gene in leukemic cells obtained from AML, CML, as well as acute lymphoblastic leukemia (ALL) and B-cell chronic lymphocytic leukemia (B-CLL). In CML and in chronic myelo-monocytic leukemia (CMML) PMNs, granulocyte colony-stimulating factor (G-CSF) specifically accumulates LAP mRNA without showing a substantial increase in the rate of transcription of the LAP gene. Once increased by G-CSF, LAP mRNA is very stable, showing a half-life of more than 4 hours in the presence of actinomycin-D. G-CSF is suggested to play a pivotal role in the modulation of LAP transcript in PMNs.

Original languageEnglish
Pages (from-to)2565-2571
Number of pages7
Issue number12
Publication statusPublished - Dec 15 1990


ASJC Scopus subject areas

  • Hematology

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