The nuclear proto-oncogene c-myb is an essential regulator of hematopoiesis, it involves in the growth, survival, proliferation and differentiation of hematopoietic cells. More recently, different cell lines and transgenic mouse studies have suggested that c-myb plays a pivotal role in the megakaryocyte-erythroid progenitor cell lineage commitment. The deletion of the proto-oncogene c-myb would lead to profoundly impaired definitive erythropoiesis, but little influence in definitive megakaryopoiesis. Moreover, transient transfection and immunoprecipitation studies have demonstrated that c-myb exerts its physiological function in normal hematopoiesis by influencing a network of regulator molecules. Now therefore, insight into the structure, function and related molecular regulation mechanism of c-myb gene can help to further clarify its function in megakaryocyte-erythroid hematopoiesis and can provide new ideas for molecular target therapy of the platelet diseases and red blood cell diseases. In this article, c-myb structure, function and related effects involved in megakaryocyte-erythroid hematopoiesis as well as related molecular mechanisms are reviewed.
Animals ; Hematopoiesis ; Humans ; Megakaryocytes ; Mice ; Proto-Oncogene Proteins c-myb

The Proto-oncogene c-myc and c-myb has been shown to be crucial in the development of the hematopoietic system. The changes in the expression of c-myc are concerned the cell proliferation and differentiation, the expression products of which play an important regulatory role in cell growth, differentiation or malignant transformation. The c-myb involves in transcription and affects cell proliferation, differentiation, apoptosis. More recently, the researches on proto-oncogene c-myc, c-myb in hematopoietic regulation have gradually increased along with development of molecular biology, molecular immunology and cell biology. Scientists point out that the directive differentiation of erythroid and megakaryocytic progenitors, and platelet abnormalities all relate to the level of their expressions. The most common thrombocytopathy includes thrombocytopenia, thrombocytosis and so on. The etiology and the mechanism of these diseases are unknown. This article reviews the structure, function and the expression of c-myc and c-myb in platelet diseases and their significance.
Blood Platelet Disorders ; genetics ; metabolism ; Humans ; Proto-Oncogene Proteins c-myb ; genetics ; metabolism ; Proto-Oncogene Proteins c-myc ; genetics ; metabolism

This study was aimed to investigate the expression, protein localization and function of Ahi-1 gene and its encoding protein in Jurkat cells. The expression of Ahi-1 mRNA and protein were measured by Northern and Western blot respectively. The plasmid containing prototype Ahi-1 was constructed and transfected into Jurkat cells. The Jurkat-A and Jurkat-C cells which either over-expressed the prototype Ahi-1 or not were obtained by selection with G418. The proliferation of the cells was assayed by XTT. The colony formation potential of the leukemia cells was checked by semisolid agarose culture. The results showed that three different transcripts of Ahi-1 (6.5,4.2 and 2 kb) were expressed in peripheral blood lymphocytes (PBLs), Jurkat and HUT78 cells. Ahi-1 protein with 140 kD localized in the cytoplasm majorly while traceless in the nucleus of Jurkat cells and PBLs from normal donor. Ahi-1 protein with 120 kD could be detected in the nucleus fraction of PBLs. Very low level of Ahi-1 protein with 120 kD was expressed in Jurkat cells. Up-regulating expression of Ahi-1 protein with 140 kD in the nucleus was found in Jurkat cells after exposure to meisoindigo, cytarabine, homoharringtonine, methotrexate and etoposide, down-regulating expression of Ahi-1 with 140 kD in the cytoplasm was observed after treatment with meisoindigo. The growth and colony formation potential were inhibited in the Jurkat-A cells, as compared to Jurkat-C cells. Total c-myb and phosphorylated AKT protein were continuously expressed in the Jurkat-C and Jurkat-A cells at similar level, but more phosphorylated c-myb was observed in Jurkat-A cells. It is concluded that three different transcripts of Ahi-1 at 6.5, 4.2 and 2 kb are detected in Jurkat cells; the Ahi-1 protein with 140 kD majorly expresses in the cytoplasm fraction and exposure to multiple chemotherapeutic compounds increased its expression in nucleus fraction. Over-expression of exogenous Ahi-1 can not only inhibit the growth and colony formation potential of Jurkat cells, but also induce the phosphorylation of c-myb in Jurkat cells.
Adaptor Proteins, Signal Transducing ; genetics ; Cell Proliferation ; Gene Expression ; Humans ; Jurkat Cells ; Plasmids ; Proto-Oncogene Proteins c-myb ; metabolism ; RNA, Messenger ; genetics ; Transfection

Using RACE with a Fagopyrum dibotrys callus cDNA library, one clone, named FdMYBP1, encoding a putative R2R3 MYB protein was identified. FdMYBP1 appeared to be a full-length cDNA of 1159 bp encoding a protein of 265 amino acids. Through structure and property analysis of FdMYBPI with bioinformational methods, it was found that the amino acid sequence of FdMYBP1 showed great homology to other MYBP with the R2R3 repeat region in the N-terminus. Southern blot analysis indicated that FdMYBP1 belongs to a single copy gene in F. dibotrys genomes. The FdMYBP1 gene has the same classic characters with other MYBP and probably involved in the pathway of flavonoid metabolisms.
Cloning, Molecular ; Fagopyrum ; genetics ; metabolism ; Gene Expression Regulation, Plant ; Molecular Sequence Data ; Plant Proteins ; genetics ; metabolism ; Proto-Oncogene Proteins c-myb ; genetics ; metabolism

The present study was carried out to investigate the effect of antisense c-myb oligodeoxynucleotides (ODN) on hCG-induced testosterone secretion in isolated rat Leydig cells. The effects of cAMP, Ca(2+) and cycloheximide (CYX) on c-Myb protein expression and testosterone secretion were also observed. The results showed that antisense c-myb ODN inhibited hCG-induced testosterone secretion of isolated rat Leydig cells in a dose-dependent manner. At the same time, integral optical density immunostaining of Myb in Leydig cells was also remarkably reduced. Nonsense tat ODN had no effect on Leydig cells. Further experiments showed that dbcAMP (100 micromol/L) obviously increased hCG-induced testosterone secretion and integral optical density (IOD) immunostaining of Myb in Leydig cells. Verapamil (10 micromol/L), a Ca(2+) channel blocker, and cycloheximide (50 microg/ml), a protein synthesis inhibitor, reduced the immunostaining of c-Myb, and also lowered hCG-induced testosterone secretion in isolated rat Leydig cells. The results indicate that c-myb closely correlates with hCG-induced testosterone secretion, and that cAMP and Ca(2+)-dependent pathway participates in the expression of protooncogene.
Animals ; Cell Separation ; Cells, Cultured ; Chorionic Gonadotropin ; pharmacology ; Leydig Cells ; secretion ; Male ; Oligodeoxyribonucleotides, Antisense ; physiology ; Proto-Oncogene Proteins c-myb ; physiology ; Rats ; Rats, Sprague-Dawley ; Testosterone ; secretion

It is important to study the mechanism of oocyte maturation because oocyte maturation is essential for the female procreation. The present study was designed to observe the effects of protooncogenes c-erbB(2) and c-myb on oocyte maturation and the upstream and downstream relationship with mitogen-activated protein kinase (MAPK) and maturation promoting factor (MPF). The investigation was designed as follows: (1) In order to explore the effects of protooncogenes on oocyte maturation, the dose- and time-dependent effects of c-erbB(2) antisense oligodeoxynucleotide (ASODN) and c-myb ASODN on oocyte maturation were examined, and the effects of oocyte microinjection with recombinant c-erbB(2) and c-myb proteins on oocyte maturation were investigated; (2) In order to study the upstream and downstream relationship among protooncogenes of c-erbB(2), c-myb and protein kinases of MAPK and MPF in regulating oocyte maturation, mouse oocytes were cultured in the medium treated with c-erbB(2) ASODN, c-myb ASODN, PD98059 (the MAPK inhibitor) or roscovitine (the MPF inhibitor) for 8 h, respectively, and the expressions of c-erbB(2) mRNA, c-myb mRNA, MAPK and MPF were examined. The results showed that both c-erbB(2) ASODN and c-myb ASODN inhibited the rate of germinal vesicle breakdown (GVBD) and the first polar (PB1) extrusion of denuded oocytes (DOs) in a dose- and time-dependent way, and delayed their maturation time significantly. When recombinant c-erbB(2) and c-myb proteins were microinjected into cytoplasm of germinal vesicle stage oocyte, we found that the GVBD rate increased by 23.1% (P<0.05) and 32.2% (P<0.05), respectively, for 6-hour culture, and the PB1 extrusion rate increased by 17.3% (P<0.05) and 23.5% (P<0.05), respectively, for 12-hour culture. RT-PCR showed that the mRNA expressions of c-erbB(2) and c-myb were detected in oocytes; c c-erbB(2) ASODN inhibited c-erbB(2) mRNA and c-myb mRNA expressions; c-myb ASODN inhibited c-myb mRNA expression but had no effect on c-erbB(2) mRNA expression. Nonsense tat ODN had no effects on the expressions of c-erbB(2) mRNA and c-myb mRNA. Neither PD98059 nor roscovitine changed the expressions of c-erbB(2) mRNA and c-myb mRNA though both of them inhibited recombinant c-erbB(2) and c-myb proteins-induced oocyte maturation. Furthermore, MAPK phosphorylation and cyclin B1 synthesis in oocytes were inhibited remarkably when oocytes were treated with c-erbB(2) ASODN, c-myb ASODN, PD98059 and roscovitine. Nonsense tat ODN had no effects on MAPK phosphorylation and cyclinB1 content. The results suggest that protooncogenes c-erbB(2) and c-myb play an important role in oocyte maturation; the effects of c-erbB(2) and c-myb depend upon the action of MAPK and MPF, and their activation is the event that occurs downstream of c-erbB(2) and c-myb in the maturation signal pathway.
Animals ; Female ; Maturation-Promoting Factor ; metabolism ; Mice ; Microinjections ; Mitogen-Activated Protein Kinases ; metabolism ; Oocytes ; physiology ; Oogenesis ; Proto-Oncogene Proteins c-myb ; metabolism ; Receptor, ErbB-2 ; metabolism ; Signal Transduction

Animals ; Liver ; metabolism ; Liver Cirrhosis ; metabolism ; Male ; Oligonucleotides, Antisense ; pharmacology ; Proto-Oncogene Proteins c-myb ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley

OBJECTIVE: To analyze the relationship of the expression of transcription factor MYB targeted regulation by miR-96 to cell invasion and apoptosis in pediatric acute myeloid leukemia (AML). METHODS: A total of 65 children with AML in The 928 Hospital of PLA Joint Logistics Support Forces from January 2017 to November 2019 were selected, including 35 cases diagnosed as primary AML and 30 cases as complete remission AML. Thirty children with immune thrombocytopenia were selected as control group. The clinical characteristics were analyzed and compared between the two groups. The levels of miR-96 and MYB in peripheral blood samples were detected by qRT-PCR and compared between the two groups. The miR-96 mimics and its negative control (NC), inhibitor-miR-96 and its NC transfected HL60 cells induced by liposome (Lipofectamine 2000), respectively, Then the expression levels of MYB were detected with Western blot and compared among four HL60 cell groups. The invasion ability of four HL60 cell groups were detected with Transwell assay. The cell proliferation ability of four HL60 cell groups were detected with MTT at 24 h, 48 h, and 72 h, respectively. The apoptosis rates of four HL60 cell groups were detected with flow cytometry. RESULTS: Compared with control group, the level of miR-96 in AML children were higher, but MYB lower (P<0.05). Compared with complete remission AML, the level of miR-96 in primary AML was higher, but MYB lower (P<0.05). Western blot analysis showed that, the expression level of MYB in the four HL60 cell groups was different (P<0.05), the lowest was in miR-96 mimics group, followed by miR-96 NC group and inhibitor-miR-96 NC group, and the highest in inhibitor-miR-96 group (P<0.05), while there was no difference between miR-96 NC group and inhibitor-miR-96 NC group (P>0.05). The promotion of over-expression level of miR-96 on the invasion ability of HL 60 cells was confirmed by Transwell assay. MTT assay showed that miR-96 could promote the proliferation of HL60 cells, inhibit the apoptosis of HL60 cells, and the effect was time-dependent manner (r=0.804). The inhibition of miR-96 on HL60 cells apoptosis was also confirmed with flow cytometry. CONCLUSION MiR-96 has significant negative effect on invasion and apoptosis of AML cells by targeting regulation MYB, and it might be a potential novel strategy for pediatric AML treatment.
Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Child ; HL-60 Cells ; Humans ; Leukemia, Myeloid, Acute/genetics* ; MicroRNAs/genetics* ; Proto-Oncogene Proteins c-myb

This study was purposed to investigate the expression level of oncogene c-myc and c-myb in leukemic cells and leukemic bone marrow stromal cells (BMSC) and the correlation with each other. The expression levels of c-myc and c-myb in those cells were examined semi-quantitatively by reverse transcription polymerase chain reaction (RT-PCR). Flow cytometry analysis was used to detect the membrane surface antigens of leukemic cells and BMSC. The karyotype was analyzed by G-banding techniques. The results showed that (1) c-myc and c-myb gene were expressed in the normal control group, the leukemic cells and BMSC of patients group. The mean expression levels of c-myb mRNA and c-myc mRNA in abnormal chromosomal leukemic cells were 1.03 ± 0.48 and 1.15 ± 0.38 respectively, which were significantly higher than those in control group (P < 0.05). In the abnormal karyotype stromal cells, the mean expression level of c-myb mRNA and c-myc mRNA were 2.08 ± 0.82 and 1.46 ± 0.29 respectively (P < 0.05). (2) The expression level of c-myc and c-myb mRNA were closely associated with patients' platelet counts (P < 0.05). (3) The expression of c-myc mRNA linearly correlated with the expression of c-myb mRNA in different prognostic groups. (4) In acute leukemic cells and BMSC, c-myc expression positively correlated with c-myb expression. (5) The expression level of c-myc in leukemic cells correlated with the expression levels of c-myc and c-myb in BMSC, respectively. It is concluded that the reduction of c-myc or c-myb expression levels may be a therapeutic regimen for leukemia.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Case-Control Studies ; Child ; Child, Preschool ; Female ; Gene Expression ; Gene Expression Regulation, Leukemic ; Genes, myb ; Genes, myc ; Humans ; Leukemia ; genetics ; metabolism ; Male ; Mesenchymal Stromal Cells ; metabolism ; Middle Aged ; Proto-Oncogene Proteins c-myb ; genetics ; metabolism ; Proto-Oncogene Proteins c-myc ; genetics ; metabolism ; Young Adult

Cells, Cultured ; Flutamide ; pharmacology ; Human Umbilical Vein Endothelial Cells ; cytology ; drug effects ; metabolism ; Humans ; Proto-Oncogene Proteins c-myb ; metabolism ; Sp1 Transcription Factor ; metabolism ; Testosterone ; antagonists & inhibitors ; physiology ; Transcription Factors ; metabolism ; Tumor Suppressor Protein p53 ; metabolism