DNA-Protein Interactions in Class III Genes

与DNA中特定碱基序列结合的蛋白质调节许多不同基因的表达。转录因子TFIIIA是锌指类蛋白质的原型，它与5S RNA基因编码区内的一个确定的碱基序列强烈结合。这种相互作用代表了转录活性复合体组装的主要步骤，一旦组装，这些复合体就会在许多轮转录中持续存在。本研究的目的是了解该蛋白质在复合体形成和转录过程中与其靶序列之间的分子相互作用。为了便于这些研究，人们开发了一种光敏交联剂，5-N3-脱氧尿苷-5‘-三磷酸，它可以代替胸苷被酶结合到DNA中。光活性DNA可以用来标记蛋白质中与DNA、纯化的TFIIIA之间的接触和非洲爪哇特定位置之间的位置或区域。5S，DNA内控区已被绘制。这使我们能够研究这种相互作用的精细结构，以了解识别过程，确定其他转录因子以及RNA聚合酶III的存在如何影响它，并寻找当聚合酶启动RNA合成和穿过TFIIIA接触位点时发生的变化。

Proteins which bind to specific base sequences in DNA regulate the expression of many different genes. Transcription factor TFIIIA, the prototype of the Zn-finger class of proteins, binds strongly to a defined base sequence contained within the coding region of 5S RNA genes. This interaction represents the primary step in assembly of a transcriptionally active complex and, once assembled, these complexes persist through many rounds of transcription. The objective of this research is an understanding of the molecular interactions between this protein and its target sequence during complex formation and transcription. To facilitate these studies, a photosensitive cross-linking reagent has been developed, 5-N3-deoxyuridine-5'- triphosphate, which can be enzymatically incorporated into DNA in place of thymidine. Photoactive DNA can be used to label sites or regions in proteins which are in close proximity to the DNA, Contacts between purified TFIIIA and specific positions in the Xenopus. 5S, DNA internal control region have been mapped. This allows examination of the fine structure of this interaction to understand the recognition process, determine how it is affected by the presence of other transcription factors as well as RNA polymerase III, and look for changes which occur as the polymerase initiates RNA synthesis and traverses the TFIIIA contact sites.