Idl is a member of the inhibitor of differentiation （Id） protein family that regulates a wide range of cell functions. Previous studies have shown that expression of the Idl gene is down-regulated by TGF-β in epith...Idl is a member of the inhibitor of differentiation （Id） protein family that regulates a wide range of cell functions. Previous studies have shown that expression of the Idl gene is down-regulated by TGF-β in epithelial cells, whereas it is up-regulated by BMP in a variety of cell types. During our study of the biological function of TGF-β1, we found that Idl can be strongly up-regulated by TGF-β1 in the human mammary gland epithelial cell line MCF10A. Quantitative real-time RT-PCR has revealed as high as 7.5-fold induction ofldl mRNA by TGF-β1 in MCF10A cells after 1 h of TGF-β1 stimulation, and this induction does not require de novo protein synthesis. Using Smad knockdown and knockout approaches, we have identified Smad3 as the responsible R-Smad for mediating transcriptional activation of the Idl gene. Chromatin immunoprecipitation assay confirms that Smad3 and Smad4 bind to the upstream region of the Idl gene. Our results demonstrate that Smad3, but not Smad2, mediates TGF-β1-dependent early transcriptional induction of Idl.展开更多
The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs...The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs a damaged cell down either a cell growth arrest or an apoptotic pathway remain poorly understood. Evidence suggests that the in vivo functions of p53 seem to balance the cell-fate choice with the type and severity of damage that occurs. The concept of antirepression, or inhibition of factors that normally keep p53 at bay, may help explain the physiological mechanisms for p53 activation. These factors also provide novel chemotherapeutic targets for the reactivation of p53 in tumors harboring a wild-type copy of the gene.展开更多
Sound recording quality, whether digital or analogue, presupposes true-to-life recording of the original audio signal. Contemporary audio media do not meet the requirements of high-fidelity recording since they do not...Sound recording quality, whether digital or analogue, presupposes true-to-life recording of the original audio signal. Contemporary audio media do not meet the requirements of high-fidelity recording since they do not insufficiently utilize the bandwidth for D/A conversion and sufficient word length. This paper deals with the values of these parameters in high-fidelity recording. The paper presents the results of a research into characteristics of faithful and high-fidelity audio recording considering the frequency range, signal-to-noise ratio and dynamic range.展开更多
文摘Idl is a member of the inhibitor of differentiation （Id） protein family that regulates a wide range of cell functions. Previous studies have shown that expression of the Idl gene is down-regulated by TGF-β in epithelial cells, whereas it is up-regulated by BMP in a variety of cell types. During our study of the biological function of TGF-β1, we found that Idl can be strongly up-regulated by TGF-β1 in the human mammary gland epithelial cell line MCF10A. Quantitative real-time RT-PCR has revealed as high as 7.5-fold induction ofldl mRNA by TGF-β1 in MCF10A cells after 1 h of TGF-β1 stimulation, and this induction does not require de novo protein synthesis. Using Smad knockdown and knockout approaches, we have identified Smad3 as the responsible R-Smad for mediating transcriptional activation of the Idl gene. Chromatin immunoprecipitation assay confirms that Smad3 and Smad4 bind to the upstream region of the Idl gene. Our results demonstrate that Smad3, but not Smad2, mediates TGF-β1-dependent early transcriptional induction of Idl.
文摘The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs a damaged cell down either a cell growth arrest or an apoptotic pathway remain poorly understood. Evidence suggests that the in vivo functions of p53 seem to balance the cell-fate choice with the type and severity of damage that occurs. The concept of antirepression, or inhibition of factors that normally keep p53 at bay, may help explain the physiological mechanisms for p53 activation. These factors also provide novel chemotherapeutic targets for the reactivation of p53 in tumors harboring a wild-type copy of the gene.
文摘Sound recording quality, whether digital or analogue, presupposes true-to-life recording of the original audio signal. Contemporary audio media do not meet the requirements of high-fidelity recording since they do not insufficiently utilize the bandwidth for D/A conversion and sufficient word length. This paper deals with the values of these parameters in high-fidelity recording. The paper presents the results of a research into characteristics of faithful and high-fidelity audio recording considering the frequency range, signal-to-noise ratio and dynamic range.
