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

Zhen-Jia Zhang,Wen-Ya Xu,Yi-Zhou Yang,Xian-Bing Wang,Ying Wang,Qiang Gao,Xuefeng Yuan,Chenggui Han,Dawei Li,Qing Cao,Ji-Hui Qiao,Dong-Min Gao,Xiao-Dong Fang,Zhi-Hang Ding

doi:10.7554/elife.53753

Zhen-Jia Zhang, Wen-Ya Xu + Show 12 more

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https://doi.org/10.7554/elife.53753

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Abstract

Carbon catabolite repression 4 (CCR4) is a conserved mRNA deadenylase regulating posttranscriptional gene expression. However, regulation of CCR4 in virus infections is less understood. Here, we characterized a pro-viral role of CCR4 in replication of a plant cytorhabdovirus, Barley yellow striate mosaic virus (BYSMV). The barley (Hordeum vulgare) CCR4 protein (HvCCR4) was identified to interact with the BYSMV phosphoprotein (P). The BYSMV P protein recruited HvCCR4 from processing bodies (PBs) into viroplasm-like bodies. Overexpression of HvCCR4 promoted BYSMV replication in plants. Conversely, knockdown of the small brown planthopper CCR4 inhibited viral accumulation in the insect vector. Biochemistry experiments revealed that HvCCR4 was recruited into N-RNA complexes by the BYSMV P protein and triggered turnover of N-bound cellular mRNAs, thereby releasing RNA-free N protein to bind viral genomic RNA for optimal viral replication. Our results demonstrate that the co-opted CCR4-mediated RNA decay facilitates cytorhabdovirus replication in plants and insects.

Highlights

In eukaryotic cells, mRNA levels determined by biosynthesis and turnover tightly regulate protein production in response to cellular environment changes (Collart, 2016; Yu et al, 2019)
Our results suggest a positive role of Carbon catabolite repression 4 (CCR4) in cytorhabdovirus infection cycles and explain how the P protein binds to N0 to prevent binding of cellular mRNAs
decapping protein 1 (DCP1)-mCherry bodies could not be adjacent with GFP-P1-207 that cannot form inclusion bodies as described in our previous study (Figure 2—figure supplement 1; Fang et al, 2019). To further investigate their co-localization, CFP-P, HvCCR4-GFP, and DCP1-mCherry were coexpressed in N. benthamiana leaves, and the results revealed that HvCCR4-GFP and CFP-P fully overlapped in punctate granules that were adjacent to DCP1-mCherry-labelled processing bodies (PBs) (Figure 2D)

Summary

Introduction

MRNA levels determined by biosynthesis and turnover tightly regulate protein production in response to cellular environment changes (Collart, 2016; Yu et al, 2019). MRNA deadenylation is primarily mediated by the CCR4-NOT complex in RNA processing bodies (PBs) that are dynamic cytoplasmic structures containing silenced mRNAs for degradation or translation repression (Parker and Sheth, 2007; Beckham and Parker, 2008; Xu and Chua, 2011; Miller and Reese, 2012; Chen and Shyu, 2013; McCormick and Khaperskyy, 2017). In the CCR4-NOT complex, carbon catabolite repression 4 (CCR4) and CCR4 associated factor (CAF1) are two deadenylases responsible for removing mRNA poly(A) tails (Collart, 2016). CAF1 interacts directly with the leucine-rich repeat (LRR) domain of CCR4 and the MIF4G domain of NOT1, and links CCR4 to the NOT1 scaffold protein of the CCR4-NOT complex

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