The CD80 （B7-1） costimulatory molecule is expressed on the surface of B cells and its expression is transcriptionally upregulated upon stimuli. To identify the region of murine CD80 promoter that direct cell type sp...The CD80 （B7-1） costimulatory molecule is expressed on the surface of B cells and its expression is transcriptionally upregulated upon stimuli. To identify the region of murine CD80 promoter that direct cell type specific gene expression, four promoters construct of CD80 gene were generated with DNA fragments fused to the GFP reporter gene. In the present study, significant promoter activity was detected with all four promoter constructs only in the murine B lymphocyte. Further, the CD80 promoter region extending from -3,005 bp to ＋273 bp in relation to the previously reported transcription start site, was identified as tissue specific region. Interestingly, the shortest 700 bp （-427/＋273） of promoter fragment was sufficient to direct the CD80 gene expression. The level of CD80 expression was also found to be modulated by exogenous stimuli in B lymphocyte. Additionally, it was demonstrated that the CD80 gene expression is regulated at the level of transcription where the inducible CD80 gene transcript was detected in B lymphocyte with increasing time.展开更多
Water-dispersed CdSe/Bi2Se3 core/shell QDs with a photothermal conversion coefficient of 27.09% have been synthesized by a cation exchange reaction. The microstructure and crystal structure of the QDs, which were conf...Water-dispersed CdSe/Bi2Se3 core/shell QDs with a photothermal conversion coefficient of 27.09% have been synthesized by a cation exchange reaction. The microstructure and crystal structure of the QDs, which were confirmed by TEM and XRD, showed that partial cation exchange occurred inside the CdSe QDs. Two main mechanisms are responsible for the excellent photothermal conversion： inhibition of radiative recombination of carriers due to the formation of type-II semiconductor heterostructures, and the large surface-to-volume ratio of the QDs. Photothermal conversion experiments indicated that the CdSe/Bi2Se3 QDs showed high photothermal conversion efficiency and excellent NIR photostability.展开更多
文摘The CD80 （B7-1） costimulatory molecule is expressed on the surface of B cells and its expression is transcriptionally upregulated upon stimuli. To identify the region of murine CD80 promoter that direct cell type specific gene expression, four promoters construct of CD80 gene were generated with DNA fragments fused to the GFP reporter gene. In the present study, significant promoter activity was detected with all four promoter constructs only in the murine B lymphocyte. Further, the CD80 promoter region extending from -3,005 bp to ＋273 bp in relation to the previously reported transcription start site, was identified as tissue specific region. Interestingly, the shortest 700 bp （-427/＋273） of promoter fragment was sufficient to direct the CD80 gene expression. The level of CD80 expression was also found to be modulated by exogenous stimuli in B lymphocyte. Additionally, it was demonstrated that the CD80 gene expression is regulated at the level of transcription where the inducible CD80 gene transcript was detected in B lymphocyte with increasing time.
基金This work has been partly supported by the National Basic Research Program of China （973 Program） No. 2011CB922204-2, and the National Natural Science Foundation of China （Nos. 11434010, 11147024, 11247025, 11304306, 11374002, and 61290303）.
文摘Water-dispersed CdSe/Bi2Se3 core/shell QDs with a photothermal conversion coefficient of 27.09% have been synthesized by a cation exchange reaction. The microstructure and crystal structure of the QDs, which were confirmed by TEM and XRD, showed that partial cation exchange occurred inside the CdSe QDs. Two main mechanisms are responsible for the excellent photothermal conversion： inhibition of radiative recombination of carriers due to the formation of type-II semiconductor heterostructures, and the large surface-to-volume ratio of the QDs. Photothermal conversion experiments indicated that the CdSe/Bi2Se3 QDs showed high photothermal conversion efficiency and excellent NIR photostability.
