NbPsbO1 Interacts Specifically with the Bamboo Mosaic Virus (BaMV) Subgenomic RNA (sgRNA) Promoter and Is Required for Efficient BaMV sgRNA Transcription
| Autor: | Chung Chi Hu, Yau-Heiu Hsu, Ying Wen Huang, Na-Sheng Lin, Menghsiao Meng, Chu I Sun, Ching Hsiu Tsai |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Chloroplasts
subgenomic RNA transcription Immunology Bamboo mosaic virus Nicotiana benthamiana RNA-dependent RNA polymerase Biology Virus Replication Microbiology Viral Proteins chloroplast Transcription (biology) Virology Tobacco Viral Replicase Complex Proteins Guide RNA Promoter Regions Genetic 3' Untranslated Regions Subgenomic mRNA Plant Proteins BaMV replication complexes RNA Photosystem II Protein Complex biology.organism_classification RNA-Dependent RNA Polymerase Cell biology Virus-Cell Interactions Potexvirus Chloroplast stroma Nicotiana benthamiana PsbO1 Insect Science RNA Viral Protein Binding |
| Zdroj: | Journal of Virology |
| ISSN: | 1098-5514 0022-538X |
| Popis: | Many positive-strand (+) RNA viruses produce subgenomic RNAs (sgRNAs) in the infection cycle through the combined activities of viral replicase and host proteins. However, knowledge about host proteins involved in direct sgRNA promoter recognition is limited. Here, in the partially purified replicase complexes from Bamboo mosaic virus (BaMV)-infected tissue, we have identified the Nicotiana benthamiana photosystem II oxygen-evolving complex protein, NbPsbO1, which specifically interacted with the promoter of sgRNA but not that of genomic RNA (gRNA). Silencing of NbPsbO1 expression suppressed BaMV accumulation in N. benthamiana protoplasts without affecting viral gRNA replication. Overexpression of wild-type NbPsbO1 stimulated BaMV sgRNA accumulation. Fluorescent microscopy examination revealed that the fluorescence associated with NbPsbO1 was redistributed from chloroplast granal thylakoids to stroma in BaMV-infected cells. Overexpression of a mislocalized mutant of NbPsbO1, dTPPsbO1-T7, inhibited BaMV RNA accumulation in N. benthamiana, whereas overexpression of an NbPsbO1 derivative, sPsbO1-T7, designed to be targeted to chloroplast stroma, upregulated the sgRNA level. Furthermore, depletion of NbPsbO1 in BaMV RdRp preparation significantly inhibited sgRNA synthesis in vitro but exerted no effect on (+) or (−) gRNA synthesis, which indicates that NbPsbO1 is required for efficient sgRNA synthesis. These results reveal a novel role for NbPsbO1 in the selective enhancement of BaMV sgRNA transcription, most likely via direct interaction with the sgRNA promoter. IMPORTANCE Production of subgenomic RNAs (sgRNAs) for efficient translation of downstream viral proteins is one of the major strategies adapted for viruses that contain a multicistronic RNA genome. Both viral genomic RNA (gRNA) replication and sgRNA transcription rely on the combined activities of viral replicase and host proteins, which recognize promoter regions for the initiation of RNA synthesis. However, compared to the cis-acting elements involved in the regulation of sgRNA synthesis, the host factors involved in sgRNA promoter recognition mostly remain to be elucidated. Here, we found a chloroplast protein, NbPsbO1, which specifically interacts with Bamboo mosaic virus (BaMV) sgRNA promoter. We showed that NbPsbO1 is relocated to the BaMV replication site in BaMV-infected cells and demonstrated that NbPsbO1 is required for efficient BaMV sgRNA transcription but exerts no effect on gRNA replication. This study provides a new insight into the regulating mechanism of viral gRNA and sgRNA synthesis. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|