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Published on: November 1, 2011
Tandem repeat sequence of duck circovirus serves as downstream sequence element to regulate viral gene expression
Zhuan-Chang Wu1, Xiao-Jing Xia2, Hao-Ran Li3
1Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No. 518, Ziyue Road, Shanghai, 200241, PR China.
A unique quadruple tandem repeat (QTR) sequence in duck circovirus (DuCV) enhances viral gene expression and mRNA stability. This QTR sequence is a novel molecular marker for DuCV genotyping and crucial for viral replication.
Area of Science:
- Virology
- Molecular Biology
- Genomics
Background:
- Duck circovirus (DuCV) possesses a small, single-stranded circular DNA genome.
- Circoviruses are known for their compact genomes and complex gene regulation.
Purpose of the Study:
- To identify and characterize unique genomic features of DuCV.
- To investigate the function of a novel quadruple tandem repeat (QTR) sequence in the DuCV genome.
- To explore the role of QTR in viral gene expression, mRNA stability, and replication.
Main Methods:
- Genome sequence analysis using the dottup program.
- Luciferase reporter assays to assess mRNA stability.
- Subgenomic constructs to analyze Cap and Rep gene expression.
- Reverse genetic studies using a DuCV-based minicircle DNA technique.
Main Results:
- A quadruple tandem repeat (QTR) sequence was identified in the intergenic region of DuCV, absent in other circoviruses.
- QTR enhances mRNA stability by functioning as a downstream sequence element (DSE) for polyadenylation signals.
- QTR plays a critical role in regulating viral gene expression (Cap and Rep).
- Deletion of QTR significantly impairs viral gene transcription and replication.
Conclusions:
- QTR is a DuCV-specific sequence and a novel molecular marker for genotyping.
- QTR is essential for DuCV gene expression, mRNA stability, and viral replication.
- This study reveals a crucial biological function of QTR in regulating DuCV's life cycle.
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