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111.
Progesterone Stimulates the Activity of the Promoters of Peripheral Myelin Protein-22 and Protein Zero Genes in Schwann Cells 总被引:7,自引:1,他引:6
Frank Désarnaud Anh N. Do Thi †Adrienne M. Brown †Greg Lemke ‡Ueli Suter §Etienne-Emile Baulieu Michael Schumacher 《Journal of neurochemistry》1998,71(4):1765-1768
Abstract: To understand better the mechanisms by which progesterone (PROG) promotes myelination in the PNS, cultured rat Schwann cells were transiently transfected with reporter constructs in which luciferase expression was controlled by the promoter region of either the peripheral myelin protein-22 (PMP22) or the protein zero (P0 ) genes. PROG stimulated the P0 promoter and promoter 1, but not promoter 2, of PMP22. The effect of PROG was specific, as estradiol and testosterone only weakly activated promoters. Dose-response curves for stimulation of both promoter constructs by PROG were biphasic. RU486, a PROG antagonist, did not abolish the effect of PROG, but stimulated promoter activities by itself. In the human carcinoma cell line T47D expressing high levels of PROG receptor, PROG did not stimulate the P0 and PMP22 promoters, whereas the promoter region of the mouse mammary tumor virus was fully activated. Thus, the activation by PROG of promoter activity of two peripheral myelin protein genes is Schwann-cell specific. 相似文献
112.
113.
铜和其他重金属离子诱导大肠杆菌抗铜启动子的研究 总被引:1,自引:0,他引:1
通过测定荧光酶活性研究了大肠杆菌抗铜基因上的两个铜诱导的启动子。结果表明,在缺少抗铜质粒pBIN19pco的情况下,启动子PpcoAbox-lux和PpcoAlong-lux的最大诱导均出现在5mmol/LCuSO4,而且PpcoAbox是一个比即PpcoAlong强的启动子;铜对两个PpcoE-lux构建的诱导的生物荧光曲线中,有两个峰,第一个峰出现在0.5mmol/LCuSO4时,第二个峰亦即最大诱导出现在约5mmol/LCuSO4时,并且PpcoElong的活性比PpcoEbox高。结果还表明,启动子PpcoE比PpcoA活性高得多;此外,由于两个Ppcoshort-lux构建均不显示任何荧光酶活性,说明Copperbox对于抗铜基因来说是非常重要甚至是必需的。在质粒pBIN19pco存在的情况下,所有启动子的最大诱导均出现在6mmol/LCuSO4时,而且比无该质粒时的相应最大诱导值高得多。以其他重金属离子进行诱导实验结果表明,锌和镍可以作为诱导物且锌的效果较好,镉和银则不能诱导抗铜系统。 相似文献
114.
Transient and stable expression of gusA fusions with rice genes in rice,barley and perennial ryegrass 总被引:5,自引:0,他引:5
115.
Summary The tumor promoter phorbol 12,13-didecanoate (PDD) significantly altered the growth properties of early passage normal human
skin cells in vitro in culture medium supplemented with elevated concentrations of selected amino acids. Continuous treatment
of cell with 10−7 or 10−8
M PDD resulted in a 5 to 10-fold increase in saturation density at early passages followed by a long-term two- to fourfold
increase. The PDD-treated cultures remained in exponential growth at cell densities greater than 10-fold higher than the control
cultures. Removal of PDD from the culture medium while the cells were at a high cell density resulted in a return to near-normal
saturation density by the subsequent passage. Anchorage independent growth of normal human cells in methylcellulose was also
promoted by PDD in a dose dependent manner, with prior subculturing in the presence of PDD being required for maximal colony
formation. The structural analog 4α-phorbol 12,13-didecanoate failed to elicit similar cellular responses.
This work was supported by grants from the Air Force Office of Scientific Research, Department of Defense (AFOSR-80-0283)
and the National Cancer Institute, Department of Health and Human Services (P-30-CA-16058). 相似文献
116.
A family of cloning vectors containing the lacUV5 promoter 总被引:16,自引:0,他引:16
117.
Michael Centrella Vicki Rosen John M. Wozney Sandra R. Casinghino Thomas L. McCarthy 《Journal of cellular biochemistry》1997,67(4):528-540
Glucocorticoid in excess produces bone loss in vivo. Consistent with this, it reduces the stimulatory effect of transforming growth factor β (TGF-β) on collagen synthesis in osteoblast-enriched cultures in vitro, where it also suppresses TGF-β binding to its type I receptors. Analogous studies with bone morphogenetic protein-2 (BMP-2) show directly opposite results. These findings prompted us to assess the effect of glucocorticoid on BMP-2 activity in cultured bone cells, and whether either agent had a dominant influence on TGF-β binding or function. BMP-2 activity was retained in part in osteoblast-enriched cultures pre-treated or co-treated with cortisol, and was fully evident when glucocorticoid exposure followed BMP-2 treatment. In addition, BMP-2 suppressed the effects of cortisol on TGF-β activity, on TGF-β binding, and on gene promoter activity directed by a glucocorticoid sensitive transfection construct. While BMP-2 also alters the function of less-differentiated bone cells, it only minimally prevented cortisol activity in these cultures. Our studies indicate that BMP-2 can oppose certain effects by cortisol on differentiated osteoblasts, and may reveal useful ways to diminish glucocorticoid-dependent bone wasting. J. Cell. Biochem. 67:528–540, 1997. © 1997 Wiley-Liss, Inc. 相似文献
118.
119.
B. V. Dawson I. G. C. Robertson W. R. Wilson L. J. Zwi J. T. Boys A. W. Green 《Bioelectromagnetics》1998,19(3):162-171
New technology involving the use of high-frequency inductive power distribution (HID) has recently been developed for use in materials handling and personnel transfer. Sinusoidal magnetic fields at a frequency of 10 kHz with field intensities of approximately 0.2 mT are generated directly between the current-carrying coils of this equipment. Effects of 10 kHz magnetic fields on cell division, migration, and differentiation have never been previously investigated. To evaluate potential effects on these parameters, a rodent reproductive study was undertaken using Wistar rats. Exposures were at 0.095, 0.24, and 0.95 mT with a background exposure of 5–10 μT. Three sets of parental rats were exposed continuously for 20–23.5 h/day to the fields: maternal rats during gestation, paternal rats for at least 45 days prior to mating and maternal rats 1 month prior to mating. Exposure phases thus covered spermatogenesis, maturation of the ovum and ovulation, fertilization, implantation, embryogenesis, organogenesis, and maturation of the fetus immediately prior to parturition. In all experiments pregnancy outcome was assessed. These studies failed to demonstrate any reproductive toxicity resulting from maternal or fetal exposure during gestation or following paternal or maternal exposure for several weeks prior to mating. No quantitative or qualitative effects on spermatogenesis occurred after exposure, and no effects on the estrous cycle or ovulation could be demonstrably linked to the 10 kHz magnetic field exposure at 0.095, 0.25, or 0.95 mT. Where possible, parental clinical chemistry and hematology were also examined. As in mouse toxicology studies previously reported, minor differences were observed between control and treated groups. These were regarded as statistically, but not biologically, significant and could not categorically be attributed to magnetic field exposure. Bioelectromagnetics 19:162–171, 1998. © 1998 Wiley-Liss, Inc. 相似文献
120.
Targeting transgene expression in research,agricultural, and environmental applications: Promoters used in plant transformation 总被引:1,自引:0,他引:1
Carol?PotenzaEmail author Lorenzo?Aleman Champa?Sengupta-Gopalan 《In vitro cellular & developmental biology. Plant》2004,40(1):1-22
Summary Plant genetic engineering has contributed substantially to the understanding of gene regulation and plant development, in
the generation of transgenic organisms for widespread usage in agriculture, and has increased the potential uses of crops
for industrial and pharmaceutical purposes. As the application of geneticallly engineered plants has widened, so has the need
to develop methods to fine-tune control of transgene expression. The availability of a broad spectrum of promoters that differ
in their ability to regulate the temporal and spatial expression patterns of the transgene can dramatically increase the successful
application of transgenic technology. Indeed, a variety of promoters in necessary at all levels of genetic engineering in
plants, from basic research discoveries, concepts and question to development of economically viable crops and plant commodities,
to addressing legitimate concerns raised about the safety and containment of transgenic plants in the environment. This review
covers the characterization and usage of a broad range of promoters employed in plant genetic engineering, including the widespread
use of plant promoters with viral and plant origin that drive constitutive expression. Also covered are selected tissue-specific
promoters from fruit, seed and grain, tubers, flowers, pistils, anther and pollen, roots and root nodules, and leaves and
green tissue. Topics also include organellar promoters, and those found in specific cell types, as well as the development
and evaluation of inducible (endogenous and exogenous origin) and synthetic plant promoter systems. Discussions on the relevance
and potential pitfalls within specific applications are included. 相似文献