The aim of this study was to investigate the effect of activating transcription factor 3 (ATF3) on the differentiation of intramuscular preadipocytes in goat, and to elucidate its possible action pathway at the molecular level. In this study, the recombinant plasmid of goat pEGFP-N1-ATF3 was constructed, and the intramuscular preadipocytes were transfected with liposomes. The relative expression levels of adipocyte differentiation marker genes were detected by quantitative real-time PCR (qRT-PCR). After transfection of goat intramuscular preadipocytes with the goat pEGFP-N1-ATF3 overexpression vector, it was found that the accumulation of lipid droplets was inhibited, and the adipocyte differentiation markers PPARγ, C/EBPα and SREBP1 were extremely significantly down-regulated (P < 0.01), while C/EBPβ and AP2 were significantly down-regulated (P < 0.05). The ATF3 binding sites were predicted to exist in the promoter regions of PPARγ, C/EBPα and AP2 by the ALGGEN PROMO program. The overexpression of goat ATF3 inhibits the accumulation of lipid droplets in intramuscular preadipocytes, and this effect may be achieved by down-regulating PPARγ, C/EBPα and AP2. These results may facilitate elucidation of the regulatory mechanism of ATF3 in regulating the differentiation of goat intramuscular preadipocytes.
3T3-L1 Cells ; Activating Transcription Factor 3/pharmacology* ; Adipocytes ; Adipogenesis/genetics* ; Animals ; CCAAT-Enhancer-Binding Protein-alpha/pharmacology* ; Cell Differentiation ; Goats ; Mice ; PPAR gamma/metabolism*

NF-Y transcription factor binds to CCAAT boxes on promoters of cell cycle regulatory genes such as cdc2, cyclin B, cdc25C, and cyclin A. We previously reported that the DNA binding activity of NF-Y is regulated by p53-p21-cdk2 pathway. CBF/HSP70 was originally identified as a transcription factor binding to the CCAAT box on the hsp70 promoter and mediates transcription repression of hsp70 pro- moter by p53. Recently it was demonstrated that CBF/HSP70 interacts and cooperates with NF-Y. In this study, we found that p53 represses the transcription of CBF/HSP70. Since transactivation ability of NF-Y is regulated in a cell cycle-dependent manner, we examined the transcription of CBF/HSP70 during the cell cycle. After synchronization of a human bladder carcinoma cell lacking functional p53 at early S phase, we infect the cells with adenovirus encoding p53. Cells infected with control virus progressed to S and G2 after release from the arrest. In contrast, cells expressing p53 enter S and G2 phases, but arrest at G2/M. The expression of CBF/HSP70 was induced at S/G2 phase in cells infected with a control virus, but kept to be repressed in cells expressing p53. Thus, these results suggest that p53 suppresses the expression of cell cycle regulatory genes though inhibiting both CCAAT binding factors, CBF/HSP70 and NF-Y.
CCAAT-Binding Factor/*metabolism ; Cell Cycle ; Cell Line, Tumor ; *Down-Regulation ; HSP70 Heat-Shock Proteins/*metabolism ; Humans ; Protein Binding ; Research Support, Non-U.S. Gov't ; *Transcription, Genetic ; Tumor Suppressor Protein p53/genetics/*metabolism

As a member of the hox gene family, hoxB4 gene encodes a class of DNA-dependent homeobox domain nucleoprotein, which is a specific transcription factor, playing an important role in regulating the balance between self-renewal and differentiation of hematopoietic stem cells (HSCs). Therefore, it is important to understand the mechanisms involved in regulating expression of hoxB4 in the HSC. Previous studies have suggested that some hoxB4 upstream regulatory factors, such as USF-1 (upstream activating factor -1), USF-2 (upstream activating factor -2) and NF-Y complex, as well as hematopoietic cytokines, such as platelet growth factor (TPO) and Wnt3a protein, play important regulatory roles in the expression of hoxB4 in hematopoietic stem cells. In this review the structure and biological characteristics of hoxB4, mechanisms involved in regulating expression of hoxB4 in the HSC are summarized.
CCAAT-Binding Factor ; metabolism ; Gene Expression Regulation ; Genes, Homeobox ; genetics ; physiology ; Hematopoietic Stem Cells ; metabolism ; Homeodomain Proteins ; genetics ; metabolism ; physiology ; Humans ; Transcription Factors ; genetics ; metabolism ; physiology ; Upstream Stimulatory Factors ; metabolism ; Wnt Proteins ; metabolism ; Wnt3 Protein ; Wnt3A Protein

OBJECTIVETo investigate the effect of a common polymorphism rs928508(A/G) in flanking region of miR-30c on the expression of pri, pre and mature miR-30c, and discuss the effect of this polymorphism on the maturing process of miR-30c in lung carcinoma.

METHODSThe pGL3-promoter-miR-30c-A and pGL3-promoter-miR-30c-G luciferase plasmids were created containing A or G allele of miR-30c flanking region. Taqman assay was used to genotype rs928508 polymorphism in 50 lung cancer tissues. RT-PCR was performed to determine the expression of pri-miR-30c, pre-miR-30c, mature miR-30c and miR-30c host gene NFYC in the 50 lung cancer tissues.

RESULTSThe luciferase expression level of the pGL3-promoter-miR-30c-A construct group was not significantly different compared with that in the the pGL3-promoter-miR-30c-G construct group (A549 cells, P = 0.758; 293A cells, P = 0.554; CHO cells, P = 0.175). The results demonstrated that rs928508(A/G) variant had no effect on the transcriptional regulation of pri-miR-30c. In the genotype-phenotype collection analysis of the 50 lung cancer tissues, the expression of pre-miR-30c and mature miR-30c for rs928508 AG/GG genotypes showed significantly lower levels compared with those in the AA genotype (P = 0.009, P = 0.011). However, the expression of pri-miR-30c showed no significant difference between AG/GG genotypes and AA genotype. Similarly, the expression of host NFYC gene was correlated with pri-miR-30c, showed no significant difference between AG/GG genotypes and AA genotype.

CONCLUSIONThe rs928508(A/G) polymorphism in flanking region of miR-30c could influence the processing from pri-miR-30c to mature miR-30c, but does not influence the transcription of pri-miR-30c.

Animals ; CCAAT-Binding Factor ; genetics ; metabolism ; CHO Cells ; Cell Line, Tumor ; Cricetinae ; Genotype ; HEK293 Cells ; Humans ; Lung Neoplasms ; genetics ; metabolism ; pathology ; MicroRNAs ; genetics ; metabolism ; Polymorphism, Single Nucleotide ; Promoter Regions, Genetic

The expression of the GLUT2 glucose transporter gene in liver is suppressed in cultured hepatoma cell lines and primary cultured hepatocytes. Earlier report showed that CCAAT/enhancer binding protein (C/EBP) regulates the promoter activity of the rat GLUT2 glucose transporter gene in liver cells. C/EBPa and C/EBPb activated the promoter activity by binding to at least two regions of the promoter and one of the C/EBP binding sites, named as site F, also has the AP-1 binding consensus. In this study, we investigated whether the AP-1 can influence on C/EBP binding to this site. The addition of recombinant c-Jun protein with liver extract caused the attenuation of C/EBP binding to site F with the appearance of a new shifted band. The shifted band was competed out with the addition of unlabeled AP-1 consensus oligonucleotide, indicating that c-Jun also can bind to site F. Another C/EBP site on GLUT2 promoter, site H, did not bind AP-1. Analysis of the DNA-protein complex revealed that C/EBP and c-Jun bind to site F in mutually exclusive manner rather than form heterodimeric complex with each other. From these results, it is suggested that the transcriptional activation of C/EBP may be influenced by c-Jun protein in certain status of the liver cells, such as acute phase response, as well as hepatocarcinogenesis.
Animals ; Base Sequence ; Binding Sites ; CCAAT-Enhancer-Binding Proteins/*metabolism ; Cell Nucleus/metabolism ; Cells, Cultured ; Liver/cytology/metabolism ; Male ; Molecular Sequence Data ; Monosaccharide Transport Proteins/*genetics/metabolism ; Promoter Regions (Genetics)/*physiology ; Proto-Oncogene Proteins c-jun/genetics/*metabolism ; Rats ; Rats, Sprague-Dawley ; Recombinant Proteins/genetics/metabolism ; Transcription Factor AP-1/genetics/metabolism

To investigate the molecular mechanisms of all-trans retinoic acid (ATRA)-induced rig-g gene expression and to better understand the signal transduction of ATRA during acute promyelocytic leukemia (APL) cell differentiation, the luciferase reporter assay, co-immunoprecipitation and chromatin immunoprecipitation were used to clarify the basic transcriptional factors, which directly initiated the expression of rig-g gene. The results showed that the expression of STAT2, IRF-9 and IRF-1 could be upregulated by ATRA with different kinetics in NB4 cells. IRF-9 was able to interact with STAT2 to form a complex, which could bind the rig-g gene promoter and trigger the rig-g expression. IRF-1 alone could also activate the reporter gene containing rig-g gene promoter, but C/EBPalpha could strongly inhibit this transcription activity of IRF-1. It is concluded that during ATRA-induced APL cell differentiation, IRF-1 is first upregulated by ATRA, and then IRF-1 increases the protein levels of IRF-9 and STAT2 with the downregulation of C/EBPalpha. The complex of IRF-9 and STAT2 is the primary transcriptional factor for rig-g gene induction. This study will be helpful for better understanding the signal transduction networks of ATRA during the course of APL cell differentiation.
CCAAT-Enhancer-Binding Protein-alpha ; metabolism ; Gene Expression Regulation, Leukemic ; drug effects ; Genes, Regulator ; drug effects ; Humans ; Interferon Regulatory Factor-1 ; metabolism ; Interferon-Stimulated Gene Factor 3, gamma Subunit ; metabolism ; Intracellular Signaling Peptides and Proteins ; genetics ; Leukemia, Promyelocytic, Acute ; genetics ; STAT2 Transcription Factor ; metabolism ; Signal Transduction ; Tretinoin ; pharmacology ; Tumor Cells, Cultured

OBJECTIVETo investigate the expressions of inflammation- and fibrosis-related genes in perinephric and subcutaneous adipose tissues in patients with adrenocorticotropic hormone (ACTH)-independent Cushing's syndrome.

METHODSThe perinephric and subcutaneous adipose tissues adipose tissues were obtained from 8 patients with ACTH-independent Cushing's syndrome undergoing laparoscopic retroperitoneal adrenalectomy. Real-time PCR was used to detect the mRNA expression levels of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metallopeptidase 2 (MMP-2), TIMP metallopeptidase inhibitor 1 (TIMP-1), early growth response 1 (EGR1), CCAAT/enhancer binding protein β(CEBPβ), uncoupling protein 1(UCP-1), PPARγ coactivator 1 alpha (PGC1α) and cell death-inducing DFFA-like effector a (CIDEA).

RESULTSThe mRNA level of CIDEA was significantly higher in the perinephric adipose tissue (peri-N) than in the subcutaneous adipose tissue (subQ) (P<0.05). The expressions of CEBPβ, UCP-1, and PGC1α mRNA in the peri-N were similar with those in the subQ. The expressions of IL-6, TIMP1 and EGR1 mRNA in the subQ were significantly higher than those in the peri-N (P<0.05). No significant difference in TNF-α and MMP-2 mRNA levels was found between peri-N and subQ.

CONCLUSIONThe expression levels of the inflammation- and fibrosis-related genes are higher in the subQ than in the peri-N of patients with ACTH-independent Cushing's syndrome, suggesting that chronic exposure to endogenous hypercortisolism may cause adipose tissue dysfunction.

Adrenalectomy ; Adrenocorticotropic Hormone ; CCAAT-Enhancer-Binding Protein-beta ; metabolism ; Cushing Syndrome ; metabolism ; surgery ; Early Growth Response Protein 1 ; metabolism ; Humans ; Matrix Metalloproteinase 2 ; metabolism ; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha ; metabolism ; Real-Time Polymerase Chain Reaction ; Subcutaneous Fat ; metabolism ; Tissue Inhibitor of Metalloproteinase-1 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; Uncoupling Protein 1 ; metabolism

To elucidate the intracellular signaling pathways for VLDL-induced VLDLR transcription, Western blot analysis was used to examine phosphorylated ERK1/2 protein. It was found that that VLDL induced an increase in ERK1/2 activity in a protein kinase C (PKC)-dependent manner in murine RAW264.7 macrophages. By using different protein kinases inhibitors or activators it was observed that the effect of VLDL-induced VLDL receptor transcription, which is monitored by RTPCR analysis of VLDL receptor mRNA, was not affected by the inhibitor of p38 kinase and cAMP analog, but completely abolished by pretreatment of the cells with PD 98059, an inhibitor of MEK and GF 109203X, an inhibitor of PKC. These results demonstrated that the PKC/ERK1/2 cascade is the essential signaling pathway by which VLDL activates VLDL receptor mRNA expression.
Animals ; CCAAT-Binding Factor ; metabolism ; Cattle ; Cells, Cultured ; Gene Expression Regulation ; Humans ; Lipoproteins, VLDL ; metabolism ; Macrophages ; cytology ; metabolism ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; Mitogen-Activated Protein Kinases ; metabolism ; physiology ; Muscle, Smooth, Vascular ; metabolism ; Phosphorylation ; RNA, Messenger ; metabolism ; Rats ; Receptors, LDL ; metabolism ; Signal Transduction ; Transcription Factors ; metabolism ; Transcription, Genetic

OBJECTIVETo explore the biological effect on NB4 cells proliferation, all-trans retinoic acid (ATRA) inducing differentiation and resistance to apoptosis by vascular endothelial growth factor (VEGF)-C cDNA transfection.

METHODSThe recombinant eukaryotic expression plasmid pcDNA3.1-VEGF-C and the vacant pcDNA3.1 vector were introduced separately into NB4 cells by lipofectamine mediation. The positive clones were screened by G418 and identified by reverse transcriptase-PCR (RT-PCR) and Western blotting. The proliferation capacity of NB4/VEGF-C cells was analysed by MTT assay and colony forming assay in vitro. After NB4/VEGF-C cells were induced by ATRA, the expression level of C/EBPalpha gene, CD11b on cells surface and morphological alteration were analysed by real-time quantitative PCR (RQ-PCR), flow cytometry (FCM), and Wright-Giemsa staining, respectively. FCM Annexin V-FITC/PI dual labeling technique was performed to investigate the etoposide (Vp16) induced NB4/VEGF-C cells apoptosis and bcl-2 gene expression level in these cells was analysed by RQ-PCR. The NB4/pcDNA3.1 cells was used as control in the above experiments.

RESULTSA stable NB4 cell line that secrets VEGF-C and its control lines were established. The proliferation capacity of the former was stronger than that of the latter. The expression level of C/EBPalpha gene of NB4/VEGF-C cells on ATRA treatment was only 1/32 that of NB4/pcDNA3.1 cells. The CD11b level and the degree of differentiation of NB4/VEGF-C were weaker than that of NB4/pcDNA3.1 cells. The percentage of apoptotic NB4/VEGF-C cells induced by Vp16 [(7.20 +/- 2.52)%] was significantly lower than that of NB4/pcDNA3.1 cells [(16.07 +/- 3.58)%] (P = 0.005), but the bcl-2 gene expression level of NB4/VEGF-C cells is 2.28-fold that of NB4/pcDNA3.1 cells.

CONCLUSIONThe VEGF-C via VEGFR-3 signaling pathway could promote the proliferation of leukemic cells by autocrine pathway and inhibit the cell differentiation mediated by ATRA and chemotherapy-induced apoptosis. VEGF-C/VEGFR-3 signaling loops might play an important role in disease progression and be potential therapeutic target for the treatment of leukemias.

Apoptosis ; drug effects ; genetics ; physiology ; Blotting, Western ; CCAAT-Enhancer-Binding Protein-alpha ; genetics ; metabolism ; CD11b Antigen ; genetics ; metabolism ; Cell Differentiation ; genetics ; physiology ; Cell Line, Tumor ; Cell Proliferation ; DNA, Complementary ; genetics ; Drug Resistance, Neoplasm ; Flow Cytometry ; Genetic Vectors ; Humans ; Leukemia, Promyelocytic, Acute ; genetics ; metabolism ; pathology ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection ; Tretinoin ; pharmacology ; Vascular Endothelial Growth Factor C ; genetics ; metabolism ; physiology