title: Transcriptional regulation of myeloid differentiation primary response (MyD) genes during myeloid differentiation is mediated by nuclear factor Y.
abstract: To understand the molecular mechanism by which interleukin-6 (IL-6) regulates myeloid differentiation primary response (MyD) genes at the onset of M1 myeloid differentiation, we used JunB as a representative MyD gene to isolate and characterize IL-6 responsive elements. An IL-6 responsive element was localized between -65 and -52 of the JunB promoter (-65/-52 IL-6RE). By using antibody and oligonucleotide competition assays in electrophoretic mobility shift assay experiments, we have shown that the heterotrimeric transcription nuclear factor Y (NF-Y) complex binds to this element. A dominant-negative form of NF-YA, ectopically expressed in M1 cells, blocked NF-Y binding to the -65/-52 IL-6RE and reduced induction of JunB by IL-6. Furthermore, inhibition of NF-Y binding also reduced MyD gene induction by IL-6 and dampened the IL-6-induced M1 differentiation program. These findings are consistent with the observation that most MyD genes contain intact NF-Y binding motifs in their promoter regions. In contrast to M1 cells, during myeloid differentiation of bone marrow (BM), there was induction of NF-Y binding to the -65/-52 IL-6RE. This induced binding can be attributed to the observed induction of NF-YA protein expression and may reflect the molecular mechanism that couples proliferation to terminal differentiation of normal myeloblasts. Similar to M1 cells, blocking NF-Y binding in BM resulted in a reduction in mature macrophages. It can be concluded that NF-Y plays a role in the transcriptional regulation of MyD genes and is required for optimum myeloid differentiation.
authors.affiliation: Fels Institute for Cancer Research and Molecular Biology and Department of Biochemistry, Temple University School of Medicine, Philadelphia, PA 19140, USA.
authors.forename: Robert M Tjin Tham
authors.initials: RM
authors.lastname: Sjin
authors.forename: Kandasamy
authors.initials: K
authors.lastname: Krishnaraju
authors.forename: Barbara
authors.initials: B
authors.lastname: Hoffman
authors.forename: Dan A
authors.initials: DA
authors.lastname: Liebermann
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D023081:CCAAT-Binding Factor / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D004347:Drug Interactions; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D016758:Genes, jun / Q000187:drug effects; D015850:Interleukin-6 / Q000235:genetics / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D022423:Myeloid Cells / Q000166:cytology* / Q000378:metabolism; D011485:Protein Binding; D020218:Response Elements; D014157:Transcription Factors / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
chemical_list: D023081:CCAAT-Binding Factor; D015850:Interleukin-6; D014157:Transcription Factors; C402244:nuclear factor Y