PLZF induces megakaryocytic development, activates Tpo receptor expression and interacts with GATA1 protein.
We investigated the expression of the PLZF gene in purified human hematopoietic progenitors induced to unilineage erythroid, granulocytic or megakaryocytic differentiation and maturation in serum-free culture. PLZF is expressed in quiescent progenitors: the expression level progressively rises through megakaryocytic development, whereas it gradually declines in erythroid and granulopoietic culture. To investigate the role of PLZF in megakaryopoiesis, we transduced the PLZF gene into the erythro-megakaryocytic TF1 cell line. PLZF overexpression upmodulates the megakaryocytic specific markers (CD42a, CD42b, CD61, PF4) and induces the thrombopoietin receptor (TpoR). The proximal promoter of the TpoR gene is activated in PLZF-expressing TF1 cells: in this promoter region, a PLZF DNA-binding site was identified by deletion constructs studies. Interestingly, PLZF and GATA1 proteins coimmunoprecipitate in PLZF-expressing TF1 cells: enforced expression of both PLZF and GATA1 in TF1 cells results in increased upregulation of megakaryocytic markers, as compared to exogenous PLZF or GATA1 alone, suggesting a functional role for the PLZF/GATA1 complex. Our data indicate that PLZF plays a significant stimulatory role in megakaryocytic development, seemingly mediated in part by induction of TpoR expression at transcriptional level. This stimulatory effect is potentiated by physical interaction of PLZF and GATA1, which are possibly assembled in a multiprotein transcriptional complex.
Labbaye
Catherine
C
Department of Hematology-Oncology, Istituto Superiore di Sanità, 00161 Rome, Italy. clabbaye@iss.it
Quaranta
Maria Teresa
MT
Pagliuca
Alfredo
A
Militi
Stefania
S
Licht
Jonathan D
JD
Testa
Ugo
U
Peschle
Cesare
C
D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D008533:Megakaryocytes / Q000502:physiology*; D009363:Neoplasm Proteins; D011401:Promoter Regions, Genetic; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D015533:Transcriptional Activation
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; C494688:GATA1 protein, human; D051741:Kruppel-Like Transcription Factors; D009363:Neoplasm Proteins; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D018121:Receptors, Cytokine; D053628:Receptors, Thrombopoietin; D014157:Transcription Factors; C082218:MPL protein, human; C092037:ZBTB16 protein, human