The Bipartite Geminivirus Coat Protein Aids BR1 Function in Viral Movement by Affecting the Accumulation of Viral Single-Stranded DNA
AUTOR(ES)
Qin, Shenwei
FONTE
American Society for Microbiology
RESUMO
The movement of bipartite geminiviruses such as squash leaf curl virus (SqLCV) requires the cooperative interaction of two essential virus-encoded movement proteins, BR1 and BL1. While the viral coat protein AR1 is not essential for systemic infection, genetic studies demonstrate that its presence masks the defective phenotype of certain BR1 missense mutants, thus suggesting that coat protein does interact with the viral movement pathway. To further examine the mechanism of this interaction, we have constructed alanine-scanning mutants of AR1 and studied them for the ability to mask the infectivity defects of appropriate BR1 mutants, for the ability to target to the nucleus and to bind viral single-stranded DNA (ssDNA) and multimerize, and for effects on the accumulation of replicated viral ssDNA. We identified a specific region of AR1 required for masking of appropriate BR1 mutants and showed that this same region of AR1 was also important for ssDNA binding and the accumulation of viral replicated ssDNA. This region of AR1 also overlapped that involved in multimerization of the coat protein. We also found that the accumulation in protoplasts of single-stranded forms of a recombinant plasmid that included the SqLCV replication origin but was too large to be encapsidated was dependent on the presence of AR1 but did not appear to require encapsidation. These findings extend our model for SqLCV movement, demonstrating that coat protein affects viral movement through its ability to induce the accumulation of replicated viral ssDNA genomes. They further suggested that encapsidation was not required for the AR1-dependent accumulation of viral ssDNA.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=110344Documentos Relacionados
- The geminivirus BR1 movement protein binds single-stranded DNA and localizes to the cell nucleus.
- A Phage Single-Stranded DNA (ssDNA) Binding Protein Complements ssDNA Accumulation of a Geminivirus and Interferes with Viral Movement
- Major coat protein and single-stranded DNA-binding protein of filamentous virus Pf3.
- Cooperation in Viral Movement: The Geminivirus BL1 Movement Protein Interacts with BR1 and Redirects It from the Nucleus to the Cell Periphery.
- Transfection of REP- mycoplasmas with viral single-stranded DNA.