IL-3 dependent regulation of Bcl-xL gene expression by STAT5 in a bone marrow derived cell line.
Activation of the Jak/STAT pathway by cytokines has been shown to regulate differentiation, proliferation or apoptosis in hematopoeitic cells. Among the Stat proteins, STAT5 is activated by a broad range of cytokines. In order to study the role of STAT5 in hematopoietic cells, we stably expressed a dominant negative form of STAT5 (STAT5A delta749) in the IL-3 dependent bone marrow derived Ba/F3 cell line. Ba/F3 cells expressing STAT5A delta749 were found to be more sensitive to apoptosis than parental or control Ba/F3 cells after IL-3 withdrawal. Analysis of the expression of the cell death regulators, Bcl-2 and Bcl-x, revealed that the level of Bcl-x was lower in Ba/F3 cells expressing STAT5A delta749 than in control cells. IL-3 regulation of Bcl-x expression at protein and mRNA levels was impaired in these cells while that of Bcl-2 expression was unaffected. We further demonstrated that the Bcl-x gene promoter contained a proximal STAT consensus sequence that bound STAT5. Transactivation of a Bcl-x gene promoter reporter construct by STAT5 was observed in Ba/F3 cells. Introduction of a mutation in the STAT binding site abolished this transactivation. These data indicate that Bcl-x is probably a STAT5 target gene. They also support the involvement of STAT5 in hematopoietic cell survival.
Dumon
S
S
Institut Cochin de Génétique Moléculaire, Institut National de la Santé et de la Recherche Médicale (INSERM U363), Hôpital Cochin, Paris, France.
Santos
S C
SC
Debierre-Grockiego
F
F
Gouilleux-Gruart
V
V
Cocault
L
L
Boucheron
C
C
Mollat
P
P
Gisselbrecht
S
S
Gouilleux
F
F
D000818:Animals; D017209:Apoptosis; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D005799:Genes, Dominant; D017930:Genes, Reporter; D019254:Genes, bcl-2; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D007377:Interleukin-3 / Q000494:pharmacology*; D051379:Mice; D008894:Milk Proteins; D011401:Promoter Regions, Genetic; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D050799:STAT5 Transcription Factor; D017384:Sequence Deletion; D015534:Trans-Activators / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic; D051020:bcl-X Protein
C494812:Bcl2l1 protein, mouse; D004268:DNA-Binding Proteins; D007377:Interleukin-3; D008894:Milk Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D011993:Recombinant Fusion Proteins; D050799:STAT5 Transcription Factor; C494093:Stat5a protein, mouse; D015534:Trans-Activators; D051020:bcl-X Protein