Search results for "Transfection"

p53 is involved in regulation of the DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) by DNA damaging agents

1998

The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) is inducible by genotoxic stress. MGMT induction results from transcriptional activation of the MGMT gene which is a specific response to DNA damage. A possible factor involved in triggering MGMT induction might be p53, because both p53 and MGMT are activated by DNA breaks. To study the effect of p53 on induction of the MGMT gene, we compared the presence of functional wild-type (wt) and mutant p53 with MGMT expression level in various mouse fibroblasts and rat hepatoma cell lines upon genotoxic treatment. Cells which responded to ionizing radiation (IR) by MGMT induction displayed functional p53, whereas in cells not expr…

Binding of Tat Protein to TAR Region of Human Immunodeficiency Virus Type 1 Blocks TAR-Mediated Activation of (2′-5′)Oligoadenylate Synthetase

1990

The TAR sequence of the 5' leader of HIV-1 long terminal repeat-directed mRNA was found to be able to bind to and to activate double-stranded RNA-dependent (2'-5')A synthetase. Binding of TAR to the purified synthetase in vitro was abolished by addition of HIV-1 Tat protein, which binds to this sequence with a high affinity. Inhibition of TAR-mediated activation of (2'-5')A synthetase by Tat was prevented in the presence of the Zn2+ and Cd2+ chelators o-phenanthroline and penicillamine, which did not impair TAR-synthetase interaction. Transient expression assays of bacterial chloramphenicol acetyltransferase (CAT) gene in HeLa cells revealed that the levels of both CAT mRNA and CAT protein …

Stress response in mesoangioblast stem cells

2006

Stem cells are presumed to survive various stresses, since they are recruited to areas of tissue damage and regeneration, where inflammatory cytokines and cytotoxic cells may result in severe cell injury. We explored the ability of mesoangioblasts to respond to different cell stresses such as heat, heavy metals and osmotic stress, by analyzing heat shock protein (HSP)70 synthesis as a stress indicator. We found that the A6 mesoangioblast stem cells constitutively synthesize HSP70 in a heat shock transcription factor (HSF)-independent way. However, A6 respond to heat shock and cadmium treatment by synthesizing HSP70 over the constitutive expression and this synthesis is HSF1 dependent. The e…

TFIIH Operates through an Expanded Proximal Promoter To Fine-Tune c-myc Expression

2004

A continuous stream of activating and repressing signals is processed by the transcription complex paused at the promoter of the c-myc proto-oncogene. The general transcription factor IIH (TFIIH) is held at promoters prior to promoter escape and so is well situated to channel the input of activators and repressors to modulate c-myc expression. We have compared cells expressing only a mutated p89 (xeroderma pigmentosum complementation group B [XPB]), the largest TFIIH subunit, with the same cells functionally complemented with the wild-type protein (XPB/wt-p89). Here, we show structural, compositional, and functional differences in transcription complexes between XPB and XPB/wt-89 cells at t…

Halloysite nanotubes-carbon dots hybrids multifunctional nanocarrier with positive cell target ability as a potential non-viral vector for oral gene …

2019

Abstract Hypothesis The use of non-viral vectors for gene therapy is hindered by their lower transfection efficiency and their lacking of self-track ability. Experiments This study aims to investigate the biological properties of halloysite nanotubes-carbon dots hybrid and its potential use as non-viral vector for oral gene therapy. The morphology and the chemical composition of the halloysite hybrid were investigated by means of high angle annular dark field scanning TEM and electron energy loss spectroscopy techniques, respectively. The cytotoxicity and the antioxidant activity were investigated by standard methods (MTS, DPPH and H2O2, respectively) using human cervical cancer HeLa cells …

Betulin binds to melanocortin receptors and antagonizes alpha-melanocyte stimulating hormone induced cAMP generation in mouse melanoma cells.

2007

Betulin is a principal component of birch bark and is known to possess a broad range of biological activities, including antiinflammatory, antiviral and anticancer actions. The present study was carried out in vitro to clarify the influence of betulin on melanocortin (MC) receptor-ergic signalling by using COS-7 cells transfected with corresponding human MC receptor DNA. The results showed that betulin binds to the human melanocortin MC1, three to five receptors with selectivity to the MC1 subtype (K(i) value 1.022 +/- 0.115 microM). Betulin binds to the MC receptors with the following potency order-MC > MC3 > MC5 > MC4. Betulin itself does not stimulate cAMP generation, however, it slightl…

High Expression of Human CYP2C in Immortalized Human Liver Epithelial Cells

2010

Cell lines stably expressing high levels of single isozymes of human CYP2C genes (CYP2C8, CYP2C9, CYP2C18 and CYP2C19) have been successfully generated by transfecting liver epithelial human cells (THLE) with an appropriate expression vector. To this aim, cDNAs encoding for each CYP2C gene were inserted by blunt-ended cloning into the unique insertion site of the singular expression vector pCMVneo. The recombinant pCMV2C8, pCMV2C9, pCMV2C18 and pCMV2C19 vectors were liposome-mediated transfected into THLE cells. The resulting transgenic cells, designated as T5-2C8, T5-2C9, T5-2C18 and T5-2C19, were cloned and the expression of the ectopic gene, mRNA and protein, was investigated by RT-PCR a…

CD83+ autologous human dendritic cells transfected with tumorpeptide CDNA: A potential tool for gene-immunotherapy?

1998

Strong Cooperativity and Loose Geometry between CUB Domains Are the Basis for Procollagen C-Proteinase Enhancer Activity

2009

Procollagen C-proteinase enhancers (PCPE-1 and -2) specifically activate bone morphogenetic protein-1 (BMP-1) and other members of the tolloid proteinase family during C-terminal processing of fibrillar collagen precursors. PCPEs consist of two CUB domains (CUB1 and CUB2) and one NTR domain separated by one short and one long linker. It was previously shown that PCPEs can strongly interact with procollagen molecules, but the exact mechanism by which they enhance BMP-1 activity remains largely unknown. Here, we used a series of deletion mutants of PCPE-1 and two chimeric constructs with repetitions of the same CUB domain to study the role of each domain and linker. Out of all the forms teste…

Mutation Analysis of Core Binding Factor A1 in Patients with Cleidocranial Dysplasia

1999

SummaryCleidocranial dysplasia (CCD) is a dominantly inherited disorder characterized by patent fontanelles, wide cranial sutures, hypoplasia of clavicles, short stature, supernumerary teeth, and other skeletal anomalies. We recently demonstrated that mutations in the transcription factor CBFA1, on chromosome 6p21, are associated with CCD. We have now analyzed the CBFA1 gene in 42 unrelated patients with CCD. In 18 patients, mutations were detected in the coding region of the CBFA1 gene, including 8 frameshift, 2 nonsense, and 9 missense mutations, as well as 2 novel polymorphisms. A cluster of missense mutations at arginine 225 (R225) identifies this residue as crucial for CBFA1 function. …