The roles of topoisomerases in the replication and expression of pseudorrabies virus

• Main Authors: Wang Chi Young, 王之仰
• Other Authors: Dr.Wong Min Liang
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/80978567698874234466

碩士 === 國立中興大學 === 獸醫學系 === 83 === Pseudorabies disease is an important infectious disease of swine, and pseudorabies virus is the causative agent. The pseudorabies virus genome is a linear double-stranded DNA(about 145kbp).The icosahedral capsid approximately 150-180nm in diameter contains 162 capsomeres , sometimes asymmetric material surrounding the capsid designated as the tegument, and an envelope containing viral glycoprotein spikes on its surface.The pseudorabies virus genome consists of two covalently linked components , designated as unique L(long) and unique S(short), which were bracketed by inverted repeat and terminal repeat.The viral DNA is synthesized by a virus-encoded DNA polymerase and a rolling circle replicating mechanism has been proposed. Our research goal is to elucidate the roles of topoisomerases in the replication and expression of pseudorabies virus. Both type I and II DNA topoisomerases have been found in prokaryotes and eukaryotes. They have important roles in cellular DNA replication and transcription. In animal viruses, topoisomerases also involve in the life cycle of viruses containing closed circular DNA( such as SV 40 virus) as well as viruses possessing double- stranded linear DNA(such as adenovirus and herpesviruses). Our results reveal that type I topoisomerase inhibitor (camptothecin) and type II topoisomerase inhibitors (VP-16 and ellipticine) could inhibit the multiplication of pseudorabies virus. The type I topoisomerase activity is essential for the DNA synthesis of pseudorabies virus.Our findings also suggest that both type I and type II topoisomerases are required for the gene expression of the pseudorabies virus genome.