CCR4, a RNA decay factor, is hijacked by a plant cytorhabdovirus phosphoprotein to facilitate virus replication

Area of Science:

• Molecular Biology
• Virology
• Plant Pathology

Background:

• Carbon catabolite repression 4 (CCR4) is a key mRNA deadenylase involved in posttranscriptional gene regulation.
• The role of CCR4 in virus infections, particularly in plants, remains largely unexplored.
• Understanding viral interactions with host cellular machinery is vital for developing control strategies.

Purpose of the Study:

• To investigate the role of CCR4 in the replication cycle of Barley yellow striate mosaic virus (BYSMV), a plant cytorhabdovirus.
• To elucidate the molecular mechanisms by which CCR4 influences BYSMV propagation in both plant and insect hosts.

Main Methods:

• Yeast three-hybrid assays to identify protein interactions.
• Agrobacterium-mediated transient expression assays to study protein localization and viral replication.
• RNA interference (RNAi) to knock down CCR4 expression in insect vectors.
• Biochemical assays to analyze N-RNA complex formation and mRNA turnover.

Main Results:

• Barley CCR4 (HvCCR4) interacts with the BYSMV phosphoprotein (P).
• HvCCR4 is recruited to viroplasm-like bodies and promotes BYSMV replication upon overexpression.
• Knockdown of CCR4 in the small brown planthopper vector reduces BYSMV accumulation.
• HvCCR4 triggers the turnover of cellular mRNAs bound to the viral N protein, facilitating viral RNA replication.

Conclusions:

• CCR4 plays a pro-viral role in BYSMV replication by facilitating the release of the viral N protein for genomic RNA binding.
• The co-option of CCR4-mediated RNA decay by BYSMV is a strategy to enhance viral propagation in both plant and insect hosts.
• Targeting CCR4 could be a potential strategy for controlling cytorhabdovirus infections.