Investigations of the Adv12E1A/ CBP/p300 complex

Transcription is a highly complex process in eukaryotes. Understanding the series of events by which genetic information is translated remains a major challenge in molecular biology. Transcriptional coactivators and corepressors play a key role within this procedure. They interact with DNA-bound transcriptional factors and are involved in such important events as chromatin remodeling and polymerase initiation. In contrast to the interactions between DNA and transcription factors our knowledge about regulating protein-protein interactions remains limited. One of those coactivators are CREB-binding protein (CBP) and its homolog p300, which take part in such basic processes as cell growth, transformation and development. Some of these functions are inhibited by adenoviral (AdV) early region 1A (E1A) oncoproteins, that block two crucial binding sites of CBP/p300, namely the TAZ2 (TAZ = transcriptional adaptor zincfinger) domain and the p160 nuclear coactivator binding domain (NCBD). The aim of this project is to determine the complex structures of the highly oncogenic AdV12 E1A bound to the TAZ2 domain, the NCBD and a construct of both domains together. Furthermore we will use relaxation dispersion methods to elucidate the mechanism of the coupled folding and binding process. This will give first insights on how oncogenic AdV12 E1A binds to CBP/p300, effectively competes with the tumor suppressor p53 and other transcriptional regulators, and thereby interferes with the normal cell cycle causing cell immortalization. In addition, a better understanding of the serotype dependent oncogeneity of E1A, which is most probably determined by the highly variable amino terminal region, will be obtained, which could form the basis for drug design or screening.