TY - JOUR
T1 - Identification and characterization of two novel transcription units of porcine circovirus 2
AU - Gao, Zhangzhao
AU - Dong, Qinfang
AU - Jiang, Yonghou
AU - Opriessnig, Tanja
AU - Wang, Jingxiu
AU - Quan, Yanping
AU - Yang, Zongqi
PY - 2013/6/18
Y1 - 2013/6/18
N2 - Porcine circovirus type 2 (PCV2) infection is associated with porcine circovirus-associated diseases in pigs, which is a serious threat to the swine industry worldwide. To date, only three open reading frames (ORFs) within the PCV2 genome have been reported: ORF1 codes for two replicase proteins (Rep and Rep'), ORF2 for the structural protein (Cap), and ORF3 for a protein implicated in cellular apoptosis. In this study, based on transcription analysis of ORF3 mRNA, a potential ORF4 mRNA was detected and characterized by real-time RT-PCR and rapid amplification of cDNA ends analysis. The results indicate that the ORF4 gene is expressed at the level of transcription in the PCV2-infected cells. In addition, a novel ORF3 associated (ORF3') mRNA was identified during virus replication in PK15 cells. Moreover, a 3' poly(A) addition signal sequence (AUUAAA, nt 258-263) was found 10-30 nucleotides upstream of the cleavage site in the novel ORF4 mRNA in the complementary-strand of the PCV2 genome. Furthermore, alternate trans-splicing was identified in the ORF3' mRNA between orientation diverse transcripts with typical GT-AG donor/acceptor junctions. Similar strategies as in this work can be applied to examine the transcription of other potential ORFs in PCV in the future.
AB - Porcine circovirus type 2 (PCV2) infection is associated with porcine circovirus-associated diseases in pigs, which is a serious threat to the swine industry worldwide. To date, only three open reading frames (ORFs) within the PCV2 genome have been reported: ORF1 codes for two replicase proteins (Rep and Rep'), ORF2 for the structural protein (Cap), and ORF3 for a protein implicated in cellular apoptosis. In this study, based on transcription analysis of ORF3 mRNA, a potential ORF4 mRNA was detected and characterized by real-time RT-PCR and rapid amplification of cDNA ends analysis. The results indicate that the ORF4 gene is expressed at the level of transcription in the PCV2-infected cells. In addition, a novel ORF3 associated (ORF3') mRNA was identified during virus replication in PK15 cells. Moreover, a 3' poly(A) addition signal sequence (AUUAAA, nt 258-263) was found 10-30 nucleotides upstream of the cleavage site in the novel ORF4 mRNA in the complementary-strand of the PCV2 genome. Furthermore, alternate trans-splicing was identified in the ORF3' mRNA between orientation diverse transcripts with typical GT-AG donor/acceptor junctions. Similar strategies as in this work can be applied to examine the transcription of other potential ORFs in PCV in the future.
U2 - 10.1007/s11262-013-0933-z
DO - 10.1007/s11262-013-0933-z
M3 - Article
C2 - 23775757
JO - Virus Genes
JF - Virus Genes
SN - 0920-8569
ER -