Expression and regulation of the thrombopoietin receptor variants MPLP and MPLK in PBMC.
The human c-mpl proto-oncogene encodes the receptor for thrombopoietin (TPO), which plays a central role in magakaryopoiesis and platelet production. Recent results showed that c-mpl mRNA expression is restricted to CD34(+) cells, megakaryocytes, and platelets. The authors analysed mRNA expression by reverse transcription and PCR (RT-PCR) of the transmembrane Mpl variants, MPLK and MPLP, in magakaryocytic cell lines, peripheral blood mononuclear cells (PBMC), lymphocytes, and monocytes. Transcription of both Mpl variants was detected in freshly isolated PBMC and the megakaryocytic cell line, DAMI, whereas none could be detected in the megakaryocytic cell line Meg-01. The cytokines TPO, interleukin 11 (IL-11), erythropoietin (EPO), and stem cell factor (SCF), which are known stimulators of megakaryopoiesis, but not interleukin3 (IL-3), increased MPLP mRNA detection in PBMC during 96 h of incubation. However, concomitantly the detection of MPLK transcripts decreased in these cells. MPLP was also detected in monocytes, B-lympocyte and T cell populations. In contrast, MPLK mRNA expression was low in monocytes, B and T cells, and no clear increase in transcription detection was observed during stimulation of these cells.
Rollinger-Holzinger
I
I
Centre Hospitalier de Luxembourg, Department of Hematology and Oncology, L-1210 Luxembourg, Austria.
Griesser
U
U
Pollak
V
V
Zwierzina
H
H
D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism*; D008533:Megakaryocytes / Q000187:drug effects / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000378:metabolism; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D015682:Retroviridae Proteins, Oncogenic / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors
D016207:Cytokines; C000715470:MAS1 protein, human; D009363:Neoplasm Proteins; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D015682:Retroviridae Proteins, Oncogenic; C082218:MPL protein, human