Jun blockade of erythropoiesis: role for repression of GATA-1 by HERP2.
Although Jun upregulation and activation have been established as critical to oncogenesis, the relevant downstream pathways remain incompletely characterized. In this study, we found that c-Jun blocks erythroid differentiation in primary human hematopoietic progenitors and, correspondingly, that Jun factors block transcriptional activation by GATA-1, the central regulator of erythroid differentiation. Mutagenesis of c-Jun suggested that its repression of GATA-1 occurs through a transcriptional mechanism involving activation of downstream genes. We identified the hairy-enhancer-of-split-related factor HERP2 as a novel gene upregulated by c-Jun. HERP2 showed physical interaction with GATA-1 and repressed GATA-1 transcriptional activation. Furthermore, transduction of HERP2 into primary human hematopoietic progenitors inhibited erythroid differentiation. These results thus define a novel regulatory pathway linking the transcription factors c-Jun, HERP2, and GATA-1. Furthermore, these results establish a connection between the Notch signaling pathway, of which the HERP factors are a critical component, and the GATA family, which participates in programming of cellular differentiation.
Elagib
Kamaleldin E
KE
University of Virginia School of Medicine, P.O. Box 800904, Charlottesville, VA 22908, USA.
Xiao
Mang
M
Hussaini
Isa M
IM
Delehanty
Lorrie L
LL
Palmer
Lisa A
LA
Racke
Frederick K
FK
Birrer
Michael J
MJ
Ganapathy-Kanniappan
Shanmugasundaram
S
Shanmugasundaram
Ganapath
G
McDevitt
Michael A
MA
Goldfarb
Adam N
AN
D018952:Antigens, CD34; D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000378:metabolism*; D050981:Erythroid-Specific DNA-Binding Factors; D004920:Erythropoiesis / Q000502:physiology*; D050982:GATA1 Transcription Factor; D005786:Gene Expression Regulation; D018257:Helix-Loop-Helix Motifs; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D020014:K562 Cells; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D018952:Antigens, CD34; D051792:Basic Helix-Loop-Helix Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050982:GATA1 Transcription Factor; D016755:Proto-Oncogene Proteins c-jun; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C494688:GATA1 protein, human; C485631:HEY1 protein, human; C405694:Hairy, HRT1 protein