Die Funktion von TTF-I bei der Transkriptions-Termination in Chromatin und in der Organisation der Chomatinstruktur der rDNA Terminatoren

利用DNA作为模板的生物过程必须与其包装成染色质相抗衡，染色质是核小体和非组蛋白蛋白的复杂阵列，其将DNA压缩成松散定义的高级结构。像转录和复制这样的所有过程都必须处理染色质，这是一个重要的额外调节层。染色质结构在转录起始中的重要性已得到充分证实。一个具体的例子是我深入研究的鼠rDNA基因。TTF-I（转录终止因子I）在染色质环境中激活核糖体基因。此外，TTF-I还终止延伸RNA聚合酶I并释放rRNA。对染色质中的转录终止一无所知。我的初步实验显示了一个特定的染色质结构的rDNA终止子区域在体内。实验还表明，多个结合位点使得TTF-I能够与rDNA终止子合作结合，并允许体外染色质上的特异性转录终止。在这个项目中，我建议研究TTF-I对rDNA终止子染色质结构的影响在体外和转录终止的影响。

Biological processes utilizing DNA as a template must contend with its packaging into chromatin, a complex array of nucleosomes and non-histone proteins which compact DNA into a loosely defined higher order structure. All processes like transcription and replication have to deal with chromatin, an essential additional layer of regulation. The importance of chromatin structure in transcription initiation is well established. A specific example is the murine rDNA gene which I studied intensively. TTF-I (Transcription Termination Factor I) activates the ribosomal gene in a chromatin context. Moreover, TTF-I also terminates the elongating RNA polymerase I and releases the rRNA. Nothing is known about transcription termination in chromatin. My initial experiments show a specific chromatin structure of the rDNA terminator region in vivo. The experiments showed as well, that multiple binding sites enable cooperative TTF-I binding to the rDNA terminator and allow specific transcription termination on chromatin in vitro. In this project I propose to study the influence of TTF-I on the rDNA terminator chromatin structure in vitro and implications for transcription termination.