Konference: 2007 49th ASH Annual Meeting - účast ČR
Kategorie:
Maligní lymfomy a leukémie
Téma: Publikace ve sborníku
Číslo abstraktu: 4121
Autoři: Mgr. Pavel Burda, Ph.D.; Mgr. Nikola Čuřík, Ph.D.; Mgr. Juraj Kokavec; Mgr. Vít Pospíšil; Arthur I. Skoultchi, Ph.D.; Jiri Zavadil, Ph.D.; Doc. MUDr. Tomáš Stopka, Ph.D.
PU.1 and GATA1 are hematopoietic lineage-specific transcription
factors that play key roles in normal myeloid and erythroid
differentiation respectively. Inappropriate expression of PU.1 in
proerythroblasts causes its binding to GATA-1 on DNA resulting in a
block of erythroid differentiation and development of murine
erythroleukemia (MEL) (Rekhtman 1999). Activation of a conditional
transgene of GATA-1 (fused with the ligand binding domain of the
estrogen receptor, ER) in MEL cells disrupts PU.1-mediated
repression in chromatin leading to re-intiation of erythroid
differentiation and cell cycle arrest (Choe 2003, Stopka 2005). In
this study we show that MEL cells can also be induced to express
myeloid differentiation programs upon PU.1-ER activation. Gene
expression microarray analysis of GATA-1-ER MEL cells and PU.1-ER
MEL cells treated with ER activators allowed us to identify mRNAs
that are regulated by both GATA-1 and PU.1 including the set of
GATA-1 targets repressed by PU.1, as well as the set of PU.1
targets repressed by GATA-1 in MEL cells. The targets of mutual
antagonism of PU.1 and GATA-1 consisted of lineage specific
transcription factors, differentiation markers and genes that cause
cell cycle arrest and antiapoptotic regulators previously
associated with myeloid and erythroid cell differentiation. To
determine if PU.1 and GATA-1 directly regulate the lineage specific
transcription factor genes, we performed chromatin
immunoprecipitation (ChIP) and analyzed the ChIP samples on
microarrays and by qPCR. We found that PU.1 and GATA-1 are
localized near PU.1 binding sites in the genes for myeloid
transcription factors Cebpa and Cbfb and near GATA-1 binding sites
in the genes for erythroid transcription factors Fog1 and Nfe2. In
addition, further ChIP experiments delineated chromatin
architecture near the binding sites for PU.1 and GATA-1 including
histone H3 content and acetylation of histone H3K9. We propose that
the mutual antagonism of PU.1 and GATA-1 in inhibiting the
respective differentiation programs is rendered through specific
changes in chromatin structure around lineage specific
transcription factors genes. These changes may contribute to the
block to differentiation evident in leukemias.
Abstract #4121 appears in Blood, Volume 110, issue 11, November 16,
2007
Keywords: PU.1|GATA-1|Leukemia
Disclosure: No relevant conflicts of interest to declare.
Session Info: Publication Only
Datum přednesení příspěvku: 8. 12. 2007