Study on the genetic information carried in DNA conformation and physical properties

T20是一种合成的180度弯曲DNA片段，模仿了部分左旋超级线圈。T20可以通过组织HeLa细胞的局部染色质结构来激活转录。本研究探讨T20是否能激活小鼠胚胎干细胞基因组的转录。发现T20甚至在胚胎干细胞中也能激活相邻的启动子。此外，即使细胞分化为肝细胞，T20的功能也保持不变。我们还利用lacO/lacI-GFP转基因检测系统对报告基因位点进行了检测。我们构建了lac操作序列的串联重复序列（64个重复），将其连接到报告结构，并将所得到的构建整合到ES细胞的基因组中。含有t20的报告蛋白位于细胞核外围。我们编写了一个程序，可以计算给定DNA的柔韧性。利用它，我们研究了酿酒酵母3号染色体所有重组热点的柔韧性特征。与酵母基因组的平均灵活性相比，这些位点的灵活性稍强。此外，我们发现外显子比内含子更灵活。这种差异可能是某些蛋白质区分这两个区域的信号。

The T20 is a synthetic 180 by bent DNA fragment that mimics a part of left-handed supercoils. T20 can activate transcription by organizing local chromatin structure in HeLa cells. This study investigated whether T20 could activate transcription in the genome of mouse ES cells. T20 was found to activate the adjacent promoter even in the ES cells. Furthermore, the function of T20 was maintained even when the cells were differentiated into hepatocytes. We also investigated the locus of the reporter by using lacO/lacI-GFP transgene detection system. We constructed a tandem-repeat of the lac operator sequences(64 repeats), ligated it to the reporter construct, and integrated the resulting construct into the genome of ES cells. The T20-containing reporter was found located in the periphery of the nucleus.II. Genetic information carried in physical properties of DNAWe made a program that can calculate the flexibility profile of a given DNA. Using it, we investigated the flexibility profiles of all of the recombination hot spots of Saccharomyces cerevisiae chromosome 3. These sites were indicated to be slightly more flexible when compared to the average flexibility of the yeast genome. In addition, we found that the exons are more flexible than the introns. This difference may function as a signal for some proteins to distinguish these two regions.