Chromatin immunoprecipitation (ChIP) studies indicate a role for CCAAT enhancer binding proteins alpha and epsilon (C/EBP alpha and C/EBP epsilon ) and CDP/cut in myeloid maturation-induced lactoferrin gene expression.
In vitro models of granulopoiesis involving the inducible expression of either CCAAT enhancer binding protein alpha (C/EBP alpha) or C/EBP epsilon in myeloid cells have been shown to lead to the induction of a granulocytic maturation program accompanied by the expression of myeloid-specific genes. Since members of the C/EBP family of transcription factors recognize and bind to similar DNA-binding motifs, it has been difficult to elucidate the specific role of each of the C/EBP family members in eliciting myeloid gene expression. In order to address this issue, we focused on the expression of the lactoferrin (LF) gene. LF expression is transcriptionally regulated in a C/EBP-dependent manner in myeloid cells. Using chromatin immunoprecipitation (ChIP) analysis we demonstrate that C/EBP alpha binds to the LF promoter in nonexpressing cells. Upon induction of maturation, C/EBP epsilon binds to the LF promoter, which correlates with LF expression. Lack of LF expression in the acute promyelocytic leukemia cell line NB4, which harbors the t(15;17) translocation, cannot be correlated with aberrant binding at the C/EBP site in the LF promoter. It is, however, associated with the persistent binding of the silencer CCAAT displacement protein (CDP/cut) to the LF promoter in these cells. We conclude that C/EBP alpha, C/EBP epsilon, and CDP/cut all play definitive roles in regulating late gene expression during normal myeloid development.
Khanna-Gupta
Arati
A
Section of Hematology, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA.
Zibello
Theresa
T
Sun
Hong
H
Gaines
Peter
P
Berliner
Nancy
N
D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000502:physiology*; D022762:CCAAT-Enhancer-Binding Proteins / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects; D002843:Chromatin / Q000378:metabolism*; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects / Q000502:physiology*; D018398:Homeodomain Proteins; D006801:Humans; D007781:Lactoferrin / Q000096:biosynthesis* / Q000235:genetics; D015473:Leukemia, Promyelocytic, Acute / Q000473:pathology; D022423:Myeloid Cells / Q000166:cytology* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000502:physiology; D009687:Nuclear Proteins / Q000502:physiology*; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012097:Repressor Proteins / Q000502:physiology*; D014157:Transcription Factors; D015533:Transcriptional Activation; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism
D022763:CCAAT-Enhancer-Binding Protein-alpha; D022762:CCAAT-Enhancer-Binding Proteins; C080632:CUX1 protein, human; D002843:Chromatin; D018398:Homeodomain Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C070790:CEBPE protein, human; D014212:Tretinoin; D007781:Lactoferrin