The c-Myb transcription factor is a critical regulator of proliferation and stem cell differentiation, and mutated alleles of c-Myb are oncogenic, but little is known about changes in c-Myb activity during the cell cycle. To map the association of c-Myb with specific target genes during the cell cycle, we developed a novel Fix-Sort-ChIP approach, in which asynchronously growing cells were fixed...

Reduced expression of the proto-oncogene c-myb appears necessary for erythroid differentiation induced by chemical agents and by the natural regulator, erythropoietin (Epo). Treatment of Epo-responsive Rauscher erythroleukemia cells with an anti-sense oligodeoxynucleotide to c-myb in the absence of other inducers downregulated myb protein markedly and caused hemoglobinization of the cells withi...

The RAG-2 gene encodes a component of the V(D)J recombinase which is essential for the assembly of antigen receptor genes in B and T lymphocytes. Previously, we reported that the transcription factor BSAP (PAX-5) regulates the murine RAG-2 promoter in B-cell lines. A partially overlapping but distinct region of the proximal RAG-2 promoter was also identified as an important element for promoter...

The myeloperoxidase (MPO) gene is transcribed specifically in immature myeloid cells and is regulated in part by a 414-bp proximal enhancer. Mutation of a core binding factor (CBF)-binding site at -288 decreased enhancer activity 30-fold in 32D cl3 myeloid cells cultured in granulocyte colony-stimulating factor (G-CSF). A novel functional analysis, linking the CBF-binding site to an enhancer de...

Rationale: c-myb null (knockout) embryonic stem cells (ESC) can differentiate into cardiomyocytes but not contractile smooth muscle cells (SMC) in embryoid bodies (EB). Objective: To define the role of c-Myb in SMC differentiation from ESC. Methods and Results: In wild-type (WT) EB, high c-Myb levels on days 0–2 of differentiation undergo ubiquitin-mediated proteosomal degradation on days 2.5–3...

MYB transcriptional elongation is regulated by an attenuator sequence within intron 1 that has been proposed to encode a RNA stem loop (SLR) followed by a polyU tract. We report that NFκBp50 can bind the SLR polyU RNA and promote MYB transcriptional elongation together with NFκBp65. We identified a conserved lysine-rich motif within the Rel homology domain (RHD) of NFκBp50, mutation of which ab...

During chemically induced differentiation of Friend virus-infected mouse erythroleukemia (MEL) cell lines, there is a biphasic down-regulation of the c-myb proto-oncogene. A plasmid containing a murine c-myb cDNA controlled by a mouse metallothionein I promoter was transfected into the C19 MEL cell line. For six transfected clones, it was found that expression of the exogenous c-myb mRNA could ...

GATA-3 and c-Myb are core elements of a transcriptionally active complex essential for human Th2 cell development and maintenance. We report herein mechanistic details concerning the role of these transcription factors in human peripheral blood Th2 cell development. Silencing c-Myb in normal human naive CD4(+) cells under Th2 cell-promoting conditions blocked up-regulation of GATA-3 and interle...

For growth, ML-1 human myeloblastic leukemia cells require insulin-like growth factor 1 together with transferrin, whereas for differentiation they depend upon transforming growth factor beta in combination with transferrin. As shown in this study, growth stimulation is accompanied by c-myb expression, whereas initiation of differentiation results in the cessation of c-myb expression through pr...

Cassava plants (Manihot esculenta Crantz) resist environmental stresses by shedding leaves in leaf pulvinus abscission zones (AZs), thus leading to adaptation to new environmental conditions. Little is known about the roles of cassava R2R3 MYB factors in regulating AZ separation. Herein, 166 cassava R2R3 MYB genes were identified. Evolutionary analysis indicated that the 166 R2R3 MYB genes coul...