Abstract
The regulation of hematopoiesis involves the interaction of specific hematopoietic cytokines with lineage-specific transcription factors, but little is known about how these cytokines might regulate the expression/activity of these different transcription factors. Here we identify the critical signal transduction pathways that mediate the interleukin 3 (IL-3)-induced enhancement of retinoic acid receptor (RAR) transcriptional activity that accompanies the IL-3-mediated commitment of the multipotent, stem cell factor (SCF)-dependent EML cell line to granulocyte/monocyte progenitors. We observe that the addition of IL-3 to EML cells induces activation of the phosphatidylinositol-3 kinase, mitogen-activated protein kinase, and Jak/Stat pathways and that Jak2 activation is the critical "proximal" mediator of the IL-3-induced enhancement of RAR activity. Constitutively active Stat5 constructs enhance both the transcriptional activity of RARs in EML cells and the commitment of these cells to granulocyte/monocyte progenitors, whereas dominant-negative Stat5 constructs inhibit this IL-3-induced enhancement of RAR transcriptional activity. We observe that the retinoic acid response element (RARE) used in our RA responsive reporter harbors overlapping Stat/RAR-binding sites. Moreover, coimmunoprecipitation studies indicate an interaction between Stat5 and RARs that is IL-3 dependent. Thus, Stat5 is an important mediator of the IL-3-induced enhancement of RAR transcriptional activity that accompanies the commitment of immature EML cells to the granulocyte/monocyte lineage. Cytokine-mediated physical and functional interactions between Stat5 and RARs may play critical roles in regulating different stages of hematopoiesis.
Publication types
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Binding Sites
-
Cell Line
-
Cell Lineage
-
DNA-Binding Proteins / genetics
-
DNA-Binding Proteins / physiology*
-
Electrophoretic Mobility Shift Assay
-
Enzyme Activation / drug effects
-
Enzyme Inhibitors / pharmacology
-
Gene Expression Regulation / drug effects
-
Gene Expression Regulation / physiology
-
Genes, Reporter
-
Granulocytes / cytology
-
Hematopoiesis / physiology
-
Hematopoietic Stem Cells / cytology
-
Hematopoietic Stem Cells / drug effects*
-
Humans
-
Interleukin-3 / pharmacology*
-
Janus Kinase 2
-
MAP Kinase Signaling System / drug effects
-
Mice
-
Milk Proteins*
-
Monocytes / cytology
-
Phosphatidylinositol 3-Kinases / drug effects
-
Phosphatidylinositol 3-Kinases / metabolism
-
Phosphoinositide-3 Kinase Inhibitors
-
Promoter Regions, Genetic
-
Protein Interaction Mapping
-
Protein-Tyrosine Kinases / physiology
-
Proto-Oncogene Proteins*
-
Receptors, Retinoic Acid / drug effects*
-
Receptors, Retinoic Acid / genetics
-
Receptors, Retinoic Acid / physiology
-
Recombinant Fusion Proteins / physiology
-
Retinoic Acid Receptor alpha
-
Retinoid X Receptors
-
STAT5 Transcription Factor
-
Signal Transduction / drug effects
-
Signal Transduction / physiology*
-
Stem Cell Factor / pharmacology
-
Trans-Activators / genetics
-
Trans-Activators / physiology*
-
Transcription Factors / drug effects*
-
Transcription Factors / genetics
-
Transcription Factors / physiology
-
Transcription, Genetic / drug effects
-
Transcription, Genetic / physiology
-
Tretinoin / metabolism
Substances
-
DNA-Binding Proteins
-
Enzyme Inhibitors
-
Interleukin-3
-
Milk Proteins
-
Phosphoinositide-3 Kinase Inhibitors
-
Proto-Oncogene Proteins
-
RARA protein, human
-
Rara protein, mouse
-
Receptors, Retinoic Acid
-
Recombinant Fusion Proteins
-
Retinoic Acid Receptor alpha
-
Retinoid X Receptors
-
STAT5 Transcription Factor
-
Stat5a protein, mouse
-
Stem Cell Factor
-
Trans-Activators
-
Transcription Factors
-
retinoic acid receptor beta
-
Tretinoin
-
Protein-Tyrosine Kinases
-
JAK2 protein, human
-
Jak2 protein, mouse
-
Janus Kinase 2