Transcriptional analysis of four white spot syndrome virus (WSSV) genes

• Main Authors: Han-Ching Wang, 王涵青
• Other Authors: Chang-Feng Dai
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/06609840441061597814

碩士 === 國立臺灣大學 === 海洋研究所 === 90 === This study focused on a transcriptional analysis of four white spot syndrome virus genes ,vp28, vp22, WSSV262 and dnapol. Result from RT-PCR, which used for a temporal expression analysis, showed that WSSV262 and dnapol are early genes expressed 2 hrs post-infection, while vp28 and vp22 are late genes expressed 12 hrs post-infection. All four WSSV genes were monogenic and produced only one species of transcript, which suggests that these genes use their own specific promoters that are not shared with other genes. An analysis of the 5’ untranslated region (UTR) of WSSV262, dnapol and other early genes showed that the major transcriptional start points were located between 26th ~ 28th nucleotides downstream of the TATA box. Comparison of the 5’ UTR of these early genes revealed a consensus sequence of (a/t)CA(g/c/t)T(a/c),which is similar to the common initiator of arthropod genes and the mammalian TdT (terminal deoxynucleotidyltransferase) gene family. No consensus sequence was found from the 5’ UTR of WSSV late genes, vp28 and vp22. In addition to the conserved poly A signal in the 3’UTR of WSSV genes, two other consensus regions were identified around the poly A addition site of these genes: the poly A addition site is located one nucleotide downstream of a conserved TTT sequence in the AAATTTA element, while several nucleotides downstream of the poly A addition site, there is the conserved sequence TTTTATT, which is similar to the TTTTNT early transcriptional termination signal of poxvirus.