Transformation growth factor β -inducible gene 22 (TSC-22) is a putative negative growth regulation and tumor suppressor gene. It has the ability to combine with other transcription factors to regulate the cell growth and apoptosis. TSC-22 is lowly expressed in many types of tumors,which may be related to the tumorgenesis and development.
Animals ; Genes, Tumor Suppressor ; Humans ; Leucine Zippers ; genetics ; Neoplasms ; physiopathology ; Repressor Proteins ; genetics ; physiology ; Transcription Factors

Common warts are close associated with HPVs infection. In this study, we amplified and sequenced the LCR fragment and E2 gene of HPV-2 that infected the patient of extensive common wart with cutaneous horns, and we constructed the recombinant CAT-reporter plasmids pBLCAT-LCR containing HPV-2 prototype or variant LCR and mammalian expression plasmids pcDNA3. 1-E2 containing prototype or variant E2 ORF individually. The promoter activities of HPV-2 variant and the transcriptional repression activities of the mutated E2 protein were evaluated by transient transfection into HeLa cells. The results showed that there were several mutations in LCR and E2 gene of HPV-2 variant. Compared with the prototype, the viral early promoter activity of variant was significantly increased uder the control of LCR. Compared with the wild type E2 protein, the transcriptional repression activities of the mutated E2 protein was abolished partially. We speculate herein that increased promoter activities and decreased repression effect of the mutated E2 protein are linked, at least partially, with the clinical phenotypes of the uncommon huge common wart.
DNA-Binding Proteins ; genetics ; physiology ; Humans ; Mutation ; Oncogene Proteins, Viral ; genetics ; physiology ; Papillomaviridae ; genetics ; Promoter Regions, Genetic ; Repressor Proteins ; physiology ; Warts ; virology

PURPOSE: The role of the Ferric Uptake Regulator (FUR) in the acid resistance of Helicobacter pylori (H. pylori) has been thought to be independent of urease. However, we demonstrated in this study that Fur influences urease activity. MATERIALS AND METHODS: A fur knockout mutant of H. pylori was constructed by replacing the Fur gene with a kanamycin resistant marker gene. The wild-type H. pylori and fur mutant were compared for survival. The integrity of the inner membrane of the bacteria was evaluated by confocal microscopy using membrane-permeant and -impermeant fluorescent DNA probes. Urease activity of intact H. pylori was measured between pH 3 and 8. Real time PCR of both strains was performed for urease genes including ureI, ureE, ureF, ureG, and ureH. RESULTS: The fur deletion affected the survival of H. pylori at pH 4. The urease activity curve of the intact fur mutant showed the same shape as the wild-type but was 3-fold lower than the wild-type at a pH of less than 5. Real time PCR revealed that the expression of all genes was consistently down-regulated in the fur mutant. CONCLUSION: The results of this study showed that fur appears to be involved in acid resistant H. pylori urease activity.
Bacterial Proteins/genetics/*physiology ; Helicobacter pylori/*enzymology/genetics ; Hydrogen-Ion Concentration ; Microscopy, Confocal ; Models, Biological ; Mutation ; Repressor Proteins/genetics/*physiology ; Urease/*metabolism

Self-renewal of hematopoietic stem cells is vital for the sustained daily production of blood cells. The Bmi-1 gene is a putative oncogene belonging to the Polycomb group family. Recent studies have shown that the Polycomb-group gene Bmi-1 is indispensable for regulation of self-renewal of normal and leukemic stem cells. The research progress on structure and function of Bmi-1 gene, and its role in self-renewal of hematopoietic stem cells was reviewed.
Cell Differentiation ; physiology ; Cell Division ; physiology ; Hematopoietic Stem Cells ; cytology ; physiology ; Humans ; Nuclear Proteins ; genetics ; physiology ; Polycomb Repressive Complex 1 ; Proto-Oncogene Proteins ; genetics ; physiology ; Repressor Proteins ; genetics ; physiology

BACKGROUNDBrain acid soluble protein 1 (BASP1) is identified as a novel potential tumor suppressor in several cancers. However, its role in thyroid cancer has not been investigated yet. In the present study, the antitumor activities of BASP1 against the growth and migration of thyroid cancer cells were evaluated.

METHODSBASP1 expression in thyroid cancer tissues and normal tissues were examined by immunohistochemical staining and the association between its expression and prognosis was analyzed. pcDNA-BASP1 carrying full length of BASP1 cDNA was constructed to restore the expression of BASP1 in thyroid cancer cell lines (BHT-101 and KMH-2). The cell proliferation in vitro and in vivo was evaluated by WST-1 assay and xenograft tumor models, respectively. Cell cycle distribution after transfection was analyzed using flow cytometry. Cell apoptosis after transfection was examined by annexin V/propidium iodide assay. The migration was examined using transwell assay.

RESULTSBASP1 expression was abundant in normal tissues while it is significantly decreased in cancer tissues (P = 0.000). pcDNA-BASP1 restored the expression of BASP1 and significantly inhibited the growth of BHT-101 and KMH-2 cells as well as xenograft tumors in nude mice (P = 0.000). pcDNA-BASP1 induced G1 arrest and apoptosis in BHT-101 and KMH-2 cells. In addition, pcDNA-BASP1 significantly inhibited the cell migration.

CONCLUSIONSDownregulation of BASP1 expression may play a role in the tumorigenesis of thyroid cancer. Restoration of BASP1 expression exerted extensive antitumor activities against growth and migration of thyroid cancer cells, which suggested that BASP1 gene might act as a potential therapeutic agent for the treatment of thyroid cancer.

Aged ; Animals ; Apoptosis ; genetics ; physiology ; Calmodulin-Binding Proteins ; genetics ; metabolism ; Cell Cycle ; genetics ; physiology ; Cell Line, Tumor ; Cell Movement ; genetics ; physiology ; Cell Proliferation ; genetics ; physiology ; Cytoskeletal Proteins ; genetics ; metabolism ; Female ; Gene Expression Regulation, Neoplastic ; genetics ; physiology ; Humans ; Male ; Membrane Proteins ; genetics ; metabolism ; Mice ; Mice, Nude ; Middle Aged ; Nerve Tissue Proteins ; genetics ; metabolism ; Repressor Proteins ; genetics ; metabolism ; Thyroid Neoplasms ; metabolism ; pathology ; Xenograft Model Antitumor Assays

OBJECTIVETo investigate the expression and possible roles of Wnt inhibitory factor-1 (Wif-1) and β-catenin in the Wnt pathway in childhood acute lymphoblastic leukemia (ALL).

METHODSThe clinical data of 35 children who had newly-diagnosed ALL and achieved complete remission on day 33 of remission induction therapy were retrospectively reviewed. The children before treatment were considered as the incipient group, and those who achieved complete remission on day 33 were considered as the remission group. Fifteen children with non-malignant hematologic diseases were enrolled as the control group. RT-PCR was used to measure the mRNA expression of Wif-1 and β-catenin. ELISA was used to measure the protein expression of Wif-1.

RESULTSCompared with the control and remission groups, the incipient group had significantly lower mRNA and protein expression of Wif-1 and significantly higher mRNA expression of β-catenin (P<0.05). In the incipient and remission groups, high-risk children showed significantly higher mRNA expression of β-catenin and significantly lower mRNA and protein expression of Wif-1 than the medium- and low-risk children (P<0.05). In the incipient and remission group, the children with T-cell acute lymphoblastic leukemia showed significantly higher mRNA expression of β-catenin and significantly lower mRNA and protein expression of Wif-1 compared with those with B-lineage acute lymphoblastic leukemia (P<0.05). In each group, there was a negative correlation between the mRNA expression of Wif-1 and β-catenin (P<0.05).

CONCLUSIONSReduced expression of Wif-1 and increased expression of β-catenin may be involved in the pathogenesis of childhood ALL, and the degree of reduction in Wif-1 and/or increase in β-catenin may be related to prognosis.

Adaptor Proteins, Signal Transducing ; genetics ; physiology ; Adolescent ; Child ; Child, Preschool ; Female ; Humans ; Infant ; Male ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; etiology ; physiopathology ; RNA, Messenger ; analysis ; Repressor Proteins ; genetics ; physiology ; Wnt Signaling Pathway ; physiology ; beta Catenin ; genetics ; physiology

Axin is a negative regulator of the Wnt/beta-catenin pathway and is involved in the regulation of axis formation and proliferation. Involvement of Axin in the regulation of other signaling pathways is poorly understood. In this study, we investigated the involvement of Akt in growth regulation by Axin in L929 fibroblasts stimulated by EGF. Akt activity was increased by EGF treatment and Ras activation, respectively. Both the EGF- and Ras-induced Akt activations were abolished by Axin induction, as revealed by both Western blot and immunocytochemical analyses. The proliferation and Akt activation induced by EGF were decreased by Axin induction, and the effects of EGF were abolished by treatment of an Akt-specific inhibitor. Therefore, Axin inhibits EGF-induced proliferation of L929 fibroblasts by blocking Akt activation.
Animals ; Cell Line ; Cell Nucleus/metabolism ; Cell Proliferation ; Epidermal Growth Factor/*pharmacology ; Fibroblasts/drug effects/physiology ; Mice ; Proto-Oncogene Proteins c-akt/antagonists & inhibitors/*metabolism ; Repressor Proteins/genetics/*physiology ; Signal Transduction ; ras Proteins/biosynthesis/genetics

BACKGROUNDBmi-1 gene determines the proliferative capacity of normal and leukemia stem cells. Expression of Bmi-1 has been found in all types of myeloid leukemia cells in both humans and mice. This study aimed at assessing the effect of antisense Bmi-1 expression on K562 cells proliferation and p16 protein (p16) expression.

METHODSA transcriptional repressor, Bmi-1 cDNA was cloned by reverse transcriptase polymerase chain reaction (RT-PCR) of its mRNA from K562 cells. A plasmid expressing antisense Bmi-1 mRNA was then constructed by reverse design of PCR primers and cloned to the plasmid pLNCX2; G418 was added to the medium after the plasmid was successfully introduced in K562 cells by lipofectin-mediated DNA transfection. The effects of the antisense expression on the proliferation of K562 cells were analyzed by using microculture tetrazolium and colony forming. Cell cycle was analyzed by using flow cytometry. The p16 expression of K562 cells was observed by immunofluorescence histochemical stain.

RESULTSK562 cells transfected with antisense Bmi-1 plasmid grew significantly slower than that of controls (the parental K562 and cells transfected with empty plasmid). The colony forming ability of antisense Bmi-1 plasmid transfected cells decreased significantly (P < 0.01) compared with controls. The p16 expression of cells transfected with antisense Bmi-1 was upgraded more apparently than that of controls.

CONCLUSIONThe antisense Bmi-1 gene can inhibit the growth of K562 cell and upgrade expression of p16 in K562 cells.

Cell Cycle ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p16 ; analysis ; Humans ; K562 Cells ; Nuclear Proteins ; antagonists & inhibitors ; genetics ; Plasmids ; Polycomb Repressive Complex 1 ; Proto-Oncogene Proteins ; antagonists & inhibitors ; genetics ; RNA, Antisense ; physiology ; Repressor Proteins ; antagonists & inhibitors ; genetics

RNA silencing is a conserved eukaryotic pathway involved in the suppression of gene expression via sequence-specific interactions that are mediated by 21-23 nt RNA molecules. During infection, RNAi can act as an innate immune system to defend against viruses. As a counter-defensive strategy, silencing suppressors are encoded by viruses to inhibit various stages of the silencing process. These suppressors are diverse in sequence and structure and act via different mechanisms. In this review, we discuss whether RNAi is a defensive strategy in mammalian host cells and whether silencing suppressors can be encoded by mammalian viruses. We also review the modes of action proposed for some silencing suppressors.
Animals ; Gene Expression Regulation, Viral ; Gene Silencing ; Host-Pathogen Interactions ; Humans ; Mammals ; virology ; MicroRNAs ; genetics ; metabolism ; Plant Viruses ; physiology ; Plants ; virology ; RNA, Small Interfering ; genetics ; metabolism ; Repressor Proteins ; genetics ; metabolism ; Viral Proteins ; genetics ; metabolism ; Viruses ; growth & development

Low density lipoprotein receptor (LDLR) plays an important role in the cholesterol homeostasis. We examined the possible circadian regulation of LDLR and mechanism(s) underlying it. In mice, blood glucose and plasma triglyceride, total and high density lipoprotein cholesterol varied distinctively throughout a day. In addition, LDLR mRNA oscillated in the liver in a functional clock-dependent manner. Accordingly, analysis of human LDLR promoter sequence revealed three putative E-boxes, raising the possible regulation of LDLR expression by E-box-binding transcription factors. To test this possibility, human LDLR promoter reporter constructs were transfected into HepG2 cells and the effects of CLOCK/BMAL1, Hes1, and Hes6 expression were analyzed. It was found that positive circadian transcription factor complex CLOCK/BMAL1 upregulated human LDLR promoter activity in a serum-independent manner, while Hes family members Hes1 and Hes6 downregulated it only under serum-depleted conditions. Both effects were mapped to proximal promoter region of human LDLR, where mutation or deletion of well-known sterol regulatory element (SRE) abolished only the repressive effect of Hes1. Interestingly, hes6 and hes1 mRNA oscillated in an anti-phasic manner in the wild-type but not in the per1-/-per2-/- mouse. Comparative analysis of mouse, rat and human hes6 genes revealed that three E-boxes are conserved among three species. Transfection and site-directed mutagenesis studies with hes6 reporter constructs confirmed that the third E-box in the exon IV is functionally induced by CLOCK/BMAL1. Taken together, these results suggest that LDLR expression is under circadian control involving CLOCK/BMAL1 and Hes family members Hes1 and Hes6.
ARNTL Transcription Factors/physiology ; Animals ; Base Sequence ; Basic Helix-Loop-Helix Transcription Factors/*genetics/metabolism/physiology ; CLOCK Proteins/physiology ; Cholesterol/blood ; *Circadian Rhythm ; E-Box Elements ; Exons ; *Gene Expression Regulation ; Hep G2 Cells ; Homeodomain Proteins/*genetics/metabolism/physiology ; Homeostasis ; Humans ; Liver/metabolism ; Male ; Mice ; Mice, Inbred C57BL ; *Promoter Regions, Genetic ; Receptors, LDL/*genetics/metabolism ; Repressor Proteins/*genetics/metabolism/physiology ; Transcription, Genetic