Sensitized-emission fluorescence resonance energy transfer （FRET） detection method based on three- channel fluorescence microscopy is widely used. Several FRET algorithms, such as NFRET, FRETN, FR, FRETR, and FC/Df, are developed recently to quantitatively gauge and compare FRET signals between different experimental groups. However, the algorithms are difficult to choose and interpret. In this letter, we optimize the suitable yellow fluorescent protein （YFP） to cyan fluorescent protein （CFP） concentration ratio range for the above FRET algorithms. We also test the effect of YFP-to-CFP concentration ratio on the calculated energy transfer efficiency E and use the optimized FRET algorithms in the analysis of fas-associated protein with death domain （FADD） self-association directly in living cells.
伴皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病（cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy,，CADASIL）是最常见的遗传性脑小血管病。NOTCH3基因错义突变致其编码的半胱氨酸发生奇数变化进而影响NOTCH3蛋白构象和功能，异常的NOTCH3蛋白具有血管平滑肌毒性并最终沉积于脑小血管而引发病变。CADASIL通常可凭典型的临床和神经影像学表现而疑诊，确诊则需基因检测或皮肤活检电镜发现小血管平滑肌细胞外嗜锇性颗粒状物质沉积或免疫组化NOTCH3ECD染色阳性。近20年来，有关CADASIL的遗传学、发病机制、临床表现及诊断技术等方面的研究已取得巨大进展，但许多重要问题并未完全阐明且有新的发现，例如NOTCH3基因的突变方式和位点、基因表型与临床表型的关系、诊断流程的优化、致病机制的深度研究和新发现、新治疗靶点和概念的探索。文章对CADASIL的遗传特征、致病机制和临床诊治技术进行了综述。
