Porcine circovirus: Transcription and DNA replication
- 作者：Andrew K. Cheung ; andrew.cheung@ars.usda.gov
- 关键词：Porcine circovirus ; Rolling-circle DNA replication
- 刊名：Virus Research
- 出版年：2012
- 期刊代码：92_01681702
- 类别：imm
- 出版时间：March, 2012
- 卷：164
- 期：1-2
- 页码：46-53
- 文件大小：858 K
摘要
This review summarizes the molecular studies pertaining to porcine circovirus (PCV) transcription and DNA replication. The genome of PCV is circular, single-stranded DNA and contains 1759-1768 nucleotides. Both the genome-strand (packaged in the virus particle) and the complementary-strand (synthesized in the new host) encode viral proteins. Among a multitude of RNAs synthesized by alternate splicing, only rep and rep鈥?are essential for virus DNA replication via the rolling-circle replication (RCR) mechanism. In contrast to other RCR biological systems which utilize only one multi-functional protein, Rep, to replicate their respective genomes, PCV requires two proteins, Rep and Rep鈥? During DNA synthesis, the PCV origin of DNA replication (Ori), which contains a pair of inverted repeats (palindrome), exists in a destabilized four-stranded configuration (the melting-pot model) and permits both the palindromic-strand and the complementary-strand to serve as templates simultaneously for initiation and termination. Inherent in the 鈥渕elting-pot鈥?model is the template-strand-switching mechanism. This mechanism is the basis for the 鈥渃orrection or conversion鈥?of any mutated nucleotide sequences engineered into either arm of the palindrome and the incorporation of 鈥渋llegitimate recombination鈥?(addition or deletion of nucleotides) events that are commonly observed at the Ori of other RCR biological systems during DNA replication.