The early gene region, EIA, of Adenovirus is responsible for two mRNAs that appear to be, along with their protein products, necessary for oncogenic transformation. The two proteins differ only in that the larger 289R protein has an extra internal sequence of 46 amino acids. This single difference must account for the functional differences between the two proteins. One function associated with this unique sequence is transactivation, the ability to transcriptionally activate the other early viral genes. In this thesis the construction and analysis of three in-frame deletion mutants are described. These three deletions, along with a fourth previously made, span the entire unique region. All three mutants had lost their transactivation ability, suggesting that the entire domain is necessary for transactivation. Transformation assays with these mutants also suggest that this function blocks transformation. Thus, the unique domain must encode another as yet unidentified function necessary for full transformation. Further evidence for another function in the unique domain comes from the differently reduced abilities of the mutants to grow on HeLa cells. Each mutant has differentially affected some function that is also necessary for lytic infection. / Thesis / Master of Science (MS)

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18181号 / 医博第3901号 / 新制||医||1004(附属図書館) / 31039 / 京都大学大学院医学研究科医学専攻 / (主査)教授 岩田 想, 教授 松田 道行, 教授 楠見 明弘 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The U.S. aquaculture industry has become well established in the last three decades, and channel catfish aquaculture is the most significant component of this industry. Virulent Aeromonas hydrophila has been a serious disease problem since 2009 in the U.S. catfish aquaculture, and Aeromonas veronii and Edwardsiella piscicida are emerging pathogens of catfish. Therefore, this study aims to address fundamental questions on virulence mechanisms of these three fish pathogens, which I expect to support the development of control measures for preventing these diseases. In this study, E. piscicida and virulent Aeromonas hydrophila (vAh) genomes were sequenced, and comparative analyses were conducted using the genome sequences. Average nucleotide identity (ANI) calculations showed that E. piscicida strains share high sequence identity, yet they are from diverse host species and geographic regions. vAh isolates share very high sequence identity, while the other A. hydrophila genomes are more distantly related to this clonal group. We applied several comparative genomics approaches to evaluate E. piscicida genomes and E. ictaluri genomes, providing valuable information about unique and shared features of these two important pathogens in the Edwardsiella genus. Comprehensive secretion system analysis of 55 A. hydrophila genomes and deletion of tssD and tssI core elements of T6SS from vAh isolate ML09-119 has provided new knowledge. We sequenced the genome of virulent Aeromonas veronii strain ML09-123 from catfish indicated that it was highly similar to an A. veronii strain from China. Evaluation of all 41 A. veronii genomes available in the National Center for Biotechnology Information (NCBI) provides a base platform to investigate in detail the molecular mechanism of A. veronii biology and virulence. Lastly, we constructed deletion mutants vAhΔsia, vAhΔent, vAhΔcol, vAhΔhfq1, vAhΔhfq2, and vAhΔhfq1Δhfq2 to determine roles of A. hydrophila secreted proteins and regulatory proteins on virulence in catfish. Results showed that sialidase (vAhΔsia) and enterotoxin (vAhΔent) mutants were significantly attenuated.