Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “promoter optimization”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1991

Abdominal and genitourinary trauma in children.

Children, especially multitrauma victims, are at significant risk for abdominal and GU trauma. Frequently, external indicators of trauma to these systems may be subtle or nonspecific. Expert assessment skills and a knowledge of potential injuries are required. Nonoperative management of these injuries is frequently the treatment of choice, requiring the nurse to understand the type of injury sustained, as well as potential complications of the injury. The nurse is often the first to detect subtle signs of deterioration in the child's condition and must be able to intervene appropriately to promote optimal outcomes for the child. The families of children who sustain abdominal or GU trauma have special teaching needs related to inhospital or home management, as well as long-term outcomes of the injury. It is the responsibility of the nurse to identify and address these needs in a timely fashion to promote optimal outcomes as well as appropriate development for the child.

Abdominal Injuries↗
PubMed2004

Restorative activities of community-dwelling elders.

This study was conducted to identify the restorative activities of community-dwelling elders. Exposure to restorative activities, such as observing nature, is associated with improved concentration, more effective cognitive functioning, and feelings of greater mental energy, peacefulness, and refreshment. Little literature exists regarding the types and benefits of restorative activities engaged in by elders, a group in need of means to promote optimal daily functioning. A qualitative descriptive design was used. Thirty (28 women, 2 men) community-dwelling elders (ages 65 to 92 years) were interviewed using open-ended questions to ascertain their perceptions of restorative activities. A content analysis of themes produced 12 categories of restorative activities: creative outlets, altruism, nature, social connections, cognitive challenges, physical activity, reading, family connections, spirituality and reflection, cultural activities, travel, and other activities. Additional studies with larger, culturally diverse samples and more men are warranted before implementing restorative interventions with elders in the hopes of promoting optimal functioning and well-being.

Aged↗
PubMed2004

Kit ligand and basic fibroblast growth factor interactions in the induction of ovarian primordial to primary follicle transition.

Ovulated eggs during a female's reproductive life are derived from a pool of primordial follicles arrested in prophase of the first meiotic division. When follicles leave the resting pool they undergo a primordial to primary follicle transition and will grow and develop until either ovulation occurs or follicles undergo atresia. Several growth factors have been implicated as acting locally within the ovary to regulate the primordial to primary follicle transition. How these growth factors may interact and cooperate to perform this vital function remains to be elucidated. The objective of the current study is to investigate interactions between kit ligand (KL) (i.e. stem cell factor) and basic fibroblast growth factor (bFGF) that promote the primordial to primary follicle transition in rat ovaries. Ovaries were removed from 4-day-old rat pups and cultured for 2 weeks with KL alone or with KL and a neutralizing antibody against bFGF. The ability of KL treatment to increase primordial follicle transition was blocked with a bFGF neutralizing antibody. In addition, ovary cultures were treated with bFGF alone or with bFGF and an anti-c-kit receptor antibody which blocks KL signaling. The ability of bFGF treatment to increase primordial follicle transition was blocked with an anti-c-kit receptor antibody. Observations indicate that both KL and bFGF must be active in order to optimally promote the changes that occur in oocytes, granulosa cells, and stromal/interstitial cells when primordial follicles initiate development. Cultured ovaries were treated with either KL or bFGF for 3 days and then bFGF and KL mRNA expression levels in the whole ovary were measured. KL was not found to regulate bFGF expression. In contrast, bFGF treatment was found to increase KL mRNA expression in cultured ovaries. These observations suggest that one function of the oocyte-derived bFGF is to increase the granulosa derived KL expression and that both KL and bFGF are required to optimally promote primordial to primary follicle transition. Elucidating the cell-cell interactions that mediate this network of specific locally derived growth factors is critical to understanding the physiology of the primordial to primary follicle transition.

Animals↗
PubMed2006

Uncomplicated urinary tract infection in women. Current practice and the effect of antibiotic resistance on empiric treatment.

OBJECTIVE: To review treatment recommendations for empiric therapy of uncomplicated urinary tract infection (uUTI) in light of evolving antibiotic resistance and to consider use of guidelines to promote optimal practice. QUALITY OF EVIDENCE: PubMed was searched and additional relevant references were identified by reviewing articles found in the search. Guidelines were identified through discussion with family practitioners. Level of evidence was assessed for recommendations. MAIN MESSAGE: Many women have uUTIs. The treatment approach is usually empiric antimicrobial therapy without obtaining pretherapy cultures. Trimethoprim-sulfamethoxazole is standard first-line empiric treatment. While resistance to this drug is increasing, it remains only about 10% in community-acquired Escherichia coli in Canada. Concerns about increased resistance have contributed to greater use of fluoroquinolones, but widespread empiric use of this class of medications might promote resistance to fluoroquinolones. Hence, fluoroquinolones should not be considered first-line therapy. While guidelines for treatment of uUTIs have been developed, their usefulness is compromised by their conflicting recommendations. CONCLUSION: Trimethoprim-sulfamethoxazole and nitrofurantoin remain first-choice empiric therapy for uUTIs. Development of guidelines relevant to family physicians and community education programs that incorporate local susceptibility patterns are important strategies for promoting optimal practice.

Anti-Infective Agents, Urinary↗
PubMed2000

Sleep loss and temporal memory.

Historical evidence suggests that sleep deprivation affects temporal memory, but this has not been studied systematically. We explored the effects of 36 hr of sleep deprivation on a neuropsychological test of temporal memory. To promote optimal performance, the test was short, novel, and interesting, and caffeine was used to reduce "sleepiness". A total of 40 young adults were randomized into four groups: control + caffeine (Cc), control + placebo (Cp), sleep deprived + caffeine (SDc), and sleep deprived + placebo (SDp). Controls slept normally. Caffeine (350 mg) or placebo were given just prior to testing. The task comprised colour photographs of unknown faces and had two components: recognition memory (distinction between previously presented and novel faces), and recency discrimination (temporal memory), when a previously shown face was presented. An interpolated task, self-ordered pointing, acted as a distraction. Caffeine had no effects within control conditions, but significantly reduced subjective sleepiness in SDc. Recognition was unaffected by sleep deprivation, whereas for recency, sleep deprivation groups scored significantly lower than controls. There was no significant improvement of recency with caffeine in the SDc group. Both sleep deprivation groups had poorer insight into their performance with recency. Self-ordered pointing remained unchanged. In conclusion, sleep deprivation impairs temporal memory (i.e. recency) despite other conditions promoting optimal performance.

Adolescent↗
PubMed2002

Identification of tissue- and cancer-selective promoters for the introduction of genes into human ovarian cancer cells.

OBJECTIVE: One potential limitation of gene therapy for epithelial tumors is the lack of tissue or tumor specificity of treatment. Tumor-selective expression of gene therapies may avoid deleterious side effects and improve the efficacy of the treatment. The aim of this study was to evaluate the tissue and tumor specificity of four different potential gene therapy promoters, to determine their usefulness in tissue-specific gene therapy of epithelial ovarian carcinomas. METHODS: Three potential epithelial cell-selective (hESE1, SLP1, OSP1) and one potential tumor-selective (hTERT) promoter were placed upstream of a luciferase construct to determine relative activity in a wide variety of normal and malignant cell lines. Transient transfection and luciferase assays were carried out in 12 epithelial ovarian (3 SV40 T antigen-transfected normal and 9 malignant) and 8 control cell lines. RESULTS: Luciferase assays revealed that the hTERT promoter presented the highest tumor selectivity. hESE1 and SLP1 promoters showed strong epithelial cell selectivity (hESE1, 16/17; SLP1, 15/17), with the OSP1 (11/17) promoter exhibiting lower epithelial selectivity. Of the potential promoters for gene therapy, hTERT promoter exhibited the strongest transcriptional activity in most of the tumor cell lines. None of the promoters exhibited strict ovarian epithelium selectivity. CONCLUSION: The hTERT promoter may be an optimal promoter for a univector gene therapy approach based on its high tumor selectivity. Utilization of multiple epithelial cell-specific promoters may result in a more tissue-selective gene therapy approach. Using a combination of promoters may prevent potential problems due to expression in nonepithelial stem cells that may constitutively express hTERT.

Adaptor Proteins, Vesicular Transport↗
PubMed1989

Ribosome associated protein(s) specifically bind(s) to the upstream activator sequence of the E. coli rrnA P1 promoter.

A sequence located upstream to the E. coli rrnA P1 promoter is required for optimal promoter activity. Deletion of this sequence reduces in vivo transcription by 90%. Substitution of this upstream activating sequence with the unrelated bent DNA sequence of the kinetoplast of Crithidia fasciculata, restores in vivo expression to high levels. Cellular proteins which are present only in exponentially growing cells bind specifically to intact rrnA P1, but do not bind to the promoter missing the upstream activating sequence. These proteins are associated with the 30S ribosomal subunits but can be washed off with concentrated salt. The correlation between the binding activity and cell growth rate suggests a role for these proteins in the transcriptional control of rRNA synthesis.

Base Sequence↗
PubMed2006

Promotion of optimized protein therapy by bioconjugation as a polymeric DDS.

In recent years, clinical applications of recombinantly produced bioactive proteins such as cytokines have attracted attention. However, since these recombinant proteins are rather unstable in vivo, their clinical use as therapeutic agents requires frequent administration at a high dosage. This regimen disrupts homeostasis and results in severe side effects. To overcome these problems, bioactive proteins have been conjugated with water-soluble synthetic (WSS) polymeric carriers. Chemical modification of a protein with a WSS polymeric carrier (bioconjugation) regulates tissue distribution, resulting in a selective increase in its desirable therapeutic effects and a decrease in undesirable side effects. Among several drug delivery system (DDS) technologies, bioconjugation has been recognized as one of the most efficient methods for improving therapeutic potency of proteins. However, for further enhancement of the therapeutic potency and safety of conjugated bioactive proteins, more precise regulation of the in vivo behavior of each protein is necessary for selective expression of its therapeutic effect. Therefore, alternative WSS polymeric modifiers in which new functions such as targeting and controlled release of drugs can be added are required for further development of bioconjugated drugs. Recently, we have synthesized a novel polymeric drug carrier, poly(vinylpyrrolidone-co-dimethyl maleic anhydride) [PVD], which was a powerful candidate drug carrier for cancer therapy. In this review, we introduce useful information that enabled us to design polymeric drug carriers and their application for protein therapy.

Antineoplastic Agents↗
PubMed1987

Analysis of the early regulatory region of the human papovavirus BK.

BKV is a human papovavirus which latently infects a majority of the world population and whose DNA has been found in human tumor tissue. Along with simian virus 40 (SV40) and JCV, it is one of several highly homologous polyomaviruses which display distinct host ranges, tissue tropisms, and transformation potentials. Determination of these properties is thought to reside, in part, in the noncoding regulatory region of these viruses. We have studied the regulation of gene expression by the early promoter and enhancer of BKV. Our results show that the early promoter of BKV consists of elements found both to the early side of and within the proximal 18 bp of the first enhancer element itself. At least one BKV regulatory element appears to be downstream of the mRNA start sites. The BKV enhancer consists of two different types of elements, three direct repeats, and an element (denoted "c") found in the 30 bp to the late side of the distal repeat. When used with the BKV promoter the enhancer repeat elements were found to be redundant, optimal promoter activity requiring only two of the three repeats plus the c element. Using the heterologous SV40 promoter the optimal BKV enhancer consisted of either three repeats or two repeats plus the c element. Subfragments of the enhancer region were capable of partial activation of homologous and heterologous promoters. We conclude that the regulation of BKV early gene expression involves novel elements arranged in ways not previously described in other papovaviruses.

Acetyltransferases↗
PubMed2004

E2A/HEB and Id3 proteins control the sensitivity to glucocorticoid-induced apoptosis in thymocytes by regulating the SRG3 expression.

The E protein family transcription factors encoded by the E2A and HEB genes are known to play critical roles in the coordinate regulation of lymphocyte development. Previous studies have shown that T cell receptor (TCR) signals rapidly induce Id3, a dominant negative antagonist of E2A activity and allow thymocytes to survive selection events in the thymus. Here we show that SRG3 acts as a novel downstream target of E2A/HeLa E box-binding (HEB) complex and modulates glucocorticoid (GC) susceptibility in thymocytes in response to TCR signals. We have identified a putative E box element in the SRG3 promoter that is required for optimal promoter activity. The transcription factors E2A and HEB specifically associate with the E box element. Moreover, E2A-HEB heterodimers cooperated to activate SRG3 transcription, which was inhibited by the expression of Id proteins. TCR-mediated signals rapidly induced Id3 via MEK/ERK activation and thereby kept the E2A/HEB complex from binding to the E box element in the SRG3 promoter. Retroviral transduction of Id3 also repressed the SRG3 expression by inhibiting the E box binding activity of the E2A/HEB complex. Intriguingly, enforced Id3 expression conferred thymocyte resistance to GCs, which could be overcome by the overexpression of SRG3. Taken together, these results suggest that Id3 may enhance the viability of immature thymocytes by at least rendering them resistant to GCs through SRG3 down-regulation.

Animals↗
PubMed2005

Enhancement of folate receptor alpha expression in tumor cells through the glucocorticoid receptor: a promising means to improved tumor detection and targeting.

The utility of the folate receptor (FR) type alpha, in a broad range of targeted therapies and as a diagnostic serum marker in cancer, is confounded by its variable tumor expression levels. FR-alpha, its mRNA and its promoter activity were coordinately up-regulated by the glucocorticoid receptor (GR) agonist, dexamethasone. Optimal promoter activation which occurred at <50 nmol/L dexamethasone was inhibited by the GR antagonist, RU486, and was enhanced by coactivators, supporting GR mediation of the dexamethasone effect. The dexamethasone response of the FR-alpha promoter progressed even after dexamethasone was withdrawn, but this delayed effect required prior de novo protein synthesis indicating an indirect regulation. The dexamethasone effect was mediated by the G/C-rich (Sp1 binding) element in the core P4 promoter and was optimal in the proper initiator context without associated changes in the complement of major Sp family proteins. Histone deacetylase (HDAC) inhibitors potentiated dexamethasone induction of FR-alpha independent of changes in GR levels. Dexamethasone/HDAC inhibitor treatment did not cause de novo FR-alpha expression in a variety of receptor-negative cells. In a murine HeLa cell tumor xenograft model, dexamethasone treatment increased both tumor-associated and serum FR-alpha. The results support the concept of increasing FR-alpha expression selectively in the receptor-positive tumors by brief treatment with a nontoxic dose of a GR agonist, alone or in combination with a well-tolerated HDAC inhibitor, to increase the efficacy of various FR-alpha-dependent therapeutic and diagnostic applications. They also offer a new paradigm for cancer diagnosis and combination therapy that includes altering a marker or a target protein expression using general transcription modulators.

Animals↗
PubMed1990

Epidermal ornithine decarboxylase induction and mouse skin tumor promotion by quinones.

The generation of reactive oxygen species and the subsequent development of a pro-oxidant state, such as occurs during the redox cycling of quinones, has been suggested to play a role in the tumor promotion. Moreover, we have recently shown that the relative tumor promoting activity of a series of structurally related anthrones correlated with their ability to undergo base-catalyzed oxidation. We therefore analyzed dose-response relationships for skin tumor promoting activity and the ability to induce epidermal ornithine decarboxylase (ODC) with a series of structurally related quinones. Single topical applications of 1,4-naphthoquinone and its 5-hydroxy analog (juglone) produced dose-dependent increases in epidermal ODC activity in the dose range 880-3520 nmol/mouse. These two quinones also promoted papilloma formation in female SENCAR mice initiated with 25 nmol 7,12-dimethylbenz[a]anthracene at doses capable of inducing epidermal ODC. The tumor promoting response with juglone (1760 nmol) was dependent upon the frequency of application, with the highest tumor response obtained with a three times per week application regimen. In contrast, neither 1,8-dihydroxy-9,10-anthraquinone nor 1,4-benzoquinone, at doses up to 1760 nmol/mouse, had any effect on epidermal ODC, nor did they possess tumor promoting activity after 31 weeks of promotion. Interestingly, 3-methyl-1,4-naphthoquinone (meadione), a relatively good redox cycling quinone, at a dose of 3520 nmol had only very weak ODC inducing activity and after 31 weeks of promotion (1760 nmol) did not produce a significant papilloma response in SENCAR mice. Thus, there was a good correlation between the ability of structurally related quinones to induce epidermal ODC and their ability to behave as tumor promoters. In contrast, a relationship between quinone redox cycling and tumor promotion was not readily apparent. Finally, under optimal promoting conditions, juglone was very effective at supporting the conversion of papillomas to carcinomas (carcinoma/papilloma ratio of 0.35). In addition, histological examination of all tumors produced during promotion with juglone revealed the presence of both kerathoacanthomas and sebaceous squamous cell carcinomas. These latter tumors, not found in the anthrone group, may be indicative of a potentially unique site and/or mechanism of action for this class of compounds.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1997

Regulation of CD34 expression in differentiating M1 cells.

CD34 is a cell surface glycoprotein expressed on hematopoietic stem and progenitor cells, but not on mature blood cells. In the present study we found that CD34 downregulation during hematopoiesis occured at the level of transcriptional initiation. Two transcription initiation sites (TISs) were identified in each of three different CD34+ cell lines; these TISs were located at 120 and 80 bp 5' of the translation start site, respectively. The promoter lacks TATA elements and, like other TATA-less promoters, the TISs conform to the consensus sequence for an INR (PyPyCAPyPyPyPy). An additional 3000 bp of upstream genomic DNA were sequenced and found to contain consensus sites for transcription factors, suggesting their potential role in gene regulation. Transient transfection assays using CD34 promoter-luciferase reporter constructs, containing sequences up to 3 kb upstream and inclusive of the TIS, indicate that this promoter drives transcription in hematopoietic CD34+ cells but not CD34+ nonhematopoietic cells. Both cell type specific expression and full promoter activity are maintained in constructs that contain as little as 454 bp upstream of the TISs. Optimal promoter activity requires the 5' untranslated region of exon 1, which contains a 51-bp element that has the potential to form an extensive secondary structure. In the plasmid DNA, however, this secondary structure was not detectable by P1 nuclease digestion. At least three proteins present in uninduced M1 nuclear extracts bind to this element. Two of the three proteins were identified as Sp 1 and Sp 3 based on supershift experiments. These data suggest that CD34 expression by hematopoietic stem and progenitor cells involves hematopoietic cell-specific factors that interact with regulatory elements within the first 230 bp of the promoter and that optimal expression requires a 60-bp segment of the 5' untranslated region.

3T3 Cells↗
PubMed2000

In vitro and in vivo analyses of constitutive and in vivo-induced promoters in attenuated vaccine and vector strains of Vibrio cholerae.

The optimal promoter for in vivo expression of heterologous antigens by live, attenuated vaccine vector strains of Vibrio cholerae is unclear; in vitro analyses of promoter activity may not accurately predict expression of antigens in vivo. We therefore introduced plasmids expressing the B subunit of cholera toxin (CtxB) under the control of a number of promoters into V. cholerae vaccine strain Peru2. We evaluated the tac promoter, which is constitutively expressed in V. cholerae, as well as the in vivo-induced V. cholerae heat shock htpG promoter and the in vivo-induced V. cholerae iron-regulated irgA promoter. The functionality of all promoters was confirmed in vitro. In vitro antigenic expression was highest in vaccine strains expressing CtxB under the control of the tac promoter (2 to 5 microgram/ml/unit of optical density at 600 nm [OD(600)]) and, under low-iron conditions, in strains containing the irgA promoter (5 microgram/ml/OD(600)). We orally inoculated mice with the various vaccine strains and used anti-CtxB immune responses as a marker for in vivo expression of CtxB. The vaccine strain expressing CtxB under the control of the tac promoter elicited the most prominent specific anti-CtxB responses in vivo (serum immunoglobulin G [IgG], P </= 0.05; serum IgA, P </= 0.05; stool IgA, P </= 0.05; bile IgA, P </= 0.05), despite the finding that the tac and irgA promoters expressed equivalent amounts of CtxB in vitro. Vibriocidal antibody titers were equivalent in all groups of animals. Our results indicate that in vitro assessment of antigen expression by vaccine and vector strains of V. cholerae may correlate poorly with immune responses in vivo and that of the promoters examined, the tac promoter may be best suited for expression from plasmids of at least certain heterologous antigens in such strains.

Animals↗
PubMed1995

Fat loading: the next magic bullet?

The depletion or reduction of bodily carbohydrate reserves is associated with fatigue during endurance exercise. Various carbohydrate supplementation and exercise regimens have been used experimentally to increase carbohydrate reserves before exercise or to maintain the availability of carbohydrate for oxidation during exercise. On the other hand, the improved endurance capability observed after aerobic training has been attributed to an increased oxidation of fat relative to carbohydrate; this carbohydrate sparing presumably delays the point at which reduced carbohydrate reserves cause fatigue. This effect has led to the suggestion that a greater availability of fat during exercise can improve performance via the carbohydrate-sparing effect of "fat loading." Although this is a plausible hypothesis, it is not supported by a sufficient number of valid, credible, and replicated studies. Thus, it appears prudent to advise endurance athletes to consume a diet that is largely carbohydrate to optimize training and competitive performance and, more importantly, to promote optimal health.

Carbohydrate Metabolism↗
PubMed1995

Evaluation of optimal stent size after endourologic incision of ureteral strictures.

The stent size necessary to promote optimal ureteral healing after an endoureterotomy is not known. We compared healing of an endoureterotomy over a 7F indwelling ureteral stent with healing over a 14F endopyelotomy stent. A midureteral stricture was created in each of 25 anesthetized female minipigs using an electrified stone basket passed retrograde. Six weeks later, the stricture was incised with a 24F cutting balloon device. Twenty pigs were randomized to receive a 7F or a 14F stent; four control pigs received neither incisions nor stents. At 1 week, a radiograph was performed to confirm proper stent position, and the stents were removed. At 3 months, a retrograde ureterogram was performed, and the ureters were examined grossly and harvested for histologic studies. Two of the ten pigs in each study group developed a recurrent stricture. The use of a 14F stent provided no advantage over the use of a smaller, more easily positioned 7F stent.

Animals↗
PubMed1993

A mouse mammary tumor virus promoter element near the transcription initiation site.

Transcription from the promoter of mouse mammary tumor virus is subject to both positive and negative control by cellular factors, and proviral promoter elements that mediate a basal level of transcription must in some way respond to these cellular regulatory signals. Several such elements, including a TATA box, a region containing three octamer-related sequences, and a binding site for nuclear factor 1, have been previously defined. Additional promoter mutations have allowed a fourth basal promoter element to be identified near the transcription initiation site between +2 and +10. Sequence alterations within this element affect transcription both in vivo and in vitro. Gel electrophoresis mobility shift and DNase I footprinting assays define a nuclear protein, termed initiation site-binding protein, that specifically recognizes this region of the promoter. Optimal levels of transcription from the mouse mammary tumor virus promoter require initiation site-binding protein, as demonstrated by a correlation between protein affinity and transcriptional activity and by specific inhibition of transcription in vitro by an oligonucleotide capable of titrating the protein from transcriptionally active fractions.

Animals↗