The Influence of Transcription, Translation and Membrane Insertion of Membrane Proteins on Chromosomal Motion

• Main Authors: Lu, Yuan-Chu, 呂元菊
• Other Authors: Chang, Yi-Ren
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/5fn562

碩士 === 國立臺灣師範大學 === 物理學系 === 106 === The defining property of prokaryotes—the absence of a nucleus—opens the possibility for interactions between the chromosome and the cytoplasmic membrane. The phenomenon of transertion is one of the important topics in the study of the interaction between chromosome and cell membrane. Transertion means the coupled transcription, translation and insertion of nascent proteins into and through membrane. Despite early evidence in its favor, this hypothesis lacked further evidence to support it for long time. Here we used single-particle tracking method to study the correlations of movement between two fluorescently labeled gene loci on both sides of the E.coli gene during which gene is expressing or not. By study chromatin motion in live cells, we hope to provide further evidence for whether the membrane protein gene will be inserted during expression. The lacY membrane protein gene had been chosen as in the lactose operon as the target membrane protein gene, and the ParB-mCherry/parC2 and the TetR-YFP/tetO pairs had been applied as the loci tags at the upstream and downstream of the lacY gene. The effect of aggregation of large amounts of RNA polymerase and off–nucleus behaviors of chromosome had also been observed during gene expression. Our results show that the chromosome loci behave fractal Brownian motions. In terms of the distribution of chromosomal locations, we found that the expression of lacY gene causes the surrounding chromosome to move in the direction of cell membrane; the expression of the cytoplasmic protein gene causes the distant chromosome to move inside the nucleus. In terms of the state of chromosome movement, it has been found that the expression of the lacY gene increases the correlation between the movements of the surrounding chromosome; the expression of the cytoplasmic protein gene causes a decrease in the motion correlation of the surrounding chromosome. We conclude that when the lacY gene is expressed, the chromosome that are clustered together will increase the tendency to move together and move toward the cell membrane. These results agree with the transertion hypothesis.