RNA Motifs and Modification Involve in RNA Long-Distance Transport in Plants.

Tao Wang,Wenna Zhang,Xiaohong Lu,Wenqian Liu,Qing Wang,Xiaojun Li,Zixi Liu,Shunli Gao,Xiaojing Zhang,Mengshuang Liu,Lihong Gao

doi:10.3389/fcell.2021.651278

Tao Wang, Wenna Zhang + Show 9 more

Open Access

https://doi.org/10.3389/fcell.2021.651278

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Abstract

A large number of RNA molecules have been found in the phloem of higher plants, and they can be transported to distant organelles through the phloem. RNA signals are important cues to be evolving in fortification strategies by long-distance transportation when suffering from various physiological challenges. So far, the mechanism of RNA selectively transportation through phloem cells is still in progress. Up to now, evidence have shown that several RNA motifs including Polypyrimidine (poly-CU) sequence, transfer RNA (tRNA)-related sequence, Single Nucleotide Mutation bound with specific RNA binding proteins to form Ribonucleotide protein (RNP) complexes could facilitate RNA mobility in plants. Furthermore, some RNA secondary structure such as tRNA-like structure (TLS), untranslation region (UTR) of mRNA, stem-loop structure of pre-miRNA also contributed to the mobility of RNAs. Latest researchs found that RNA methylation such as methylated 5′ cytosine (m5C) played an important role in RNA transport and function. These studies lay a theoretical foundation to uncover the mechanism of RNA transport. We aim to provide ideas and clues to inspire future research on the function of RNA motifs in RNA long-distance transport, furthermore to explore the underlying mechanism of RNA systematic signaling.

Highlights

As the main transportation pathway, higher plants’ vascular system, including xylem and phloem plays an important role in process of growth and development (Lucas et al, 2013)
While tRNAIle with little or no methylated cytosines was non-mobile (Zhang et al, 2016). Such base modifications have the potential to change the structure of the transcript and interact with cytokines, and may mediate long-distance movement of the transcript. 5mC methylation increases the stability of tRNA-like structure (TLS) and mRNA in Arabidopsis, thereby increasing the stability and ability of RNA transport
The mechanism by which RNA binding protein forms an RNA-protein complex to mediate transport is proposed in the research of small RNA (Yoo et al, 2004; Ham et al, 2014) and viroid RNA (Pallas and Gómez, 2013)

Summary

INTRODUCTION

As the main transportation pathway, higher plants’ vascular system, including xylem and phloem plays an important role in process of growth and development (Lucas et al, 2013). Secondary and tertiary structure of viroid may recognize RNA binding protein to facilitate long-distance transport in phloem of plants (Leontis et al, 2002, 2006; Noller, 2005; Zhong et al, 2007). Despite the sequence of UTR region, the secondary structures, including stem-loop, hairpin, pseudo-knots or the tertiary structures such as tRNA or TLS in the UTR region crucial for the mRNA phloem transportation These structures may have high affinity to RNA-binding proteins which assist mRNA phloem transportation (Tolstyko et al, 2020). While tRNAIle with little or no methylated cytosines was non-mobile (Zhang et al, 2016) Such base modifications have the potential to change the structure of the transcript and interact with cytokines, and may mediate long-distance movement of the transcript.

DISCUSSION

Findings

CONCLUSION