RNA-stabilization factors in chloroplasts of vascular plants.

Lisa-Marie Schmid,Nikolay Manavski,Jörg Meurer,Steven Gutteridge

doi:10.1042/ebc20170061

Lisa-Marie Schmid, Nikolay Manavski + Show 2 more

Open Access

https://doi.org/10.1042/ebc20170061

Copy DOI

Abstract

In contrast to the cyanobacterial ancestor, chloroplast gene expression is predominantly governed on the post-transcriptional level such as modifications of the RNA sequence, decay rates, exo- and endonucleolytic processing as well as translational events. The concerted function of numerous chloroplast RNA-binding proteins plays a fundamental and often essential role in all these processes but our understanding of their impact in regulation of RNA degradation is only at the beginning. Moreover, metabolic processes and post-translational modifications are thought to affect the function of RNA protectors. These protectors contain a variety of different RNA-recognition motifs, which often appear as multiple repeats. They are required for normal plant growth and development as well as diverse stress responses and acclimation processes. Interestingly, most of the protectors are plant specific which reflects a fast-evolving RNA metabolism in chloroplasts congruent with the diverging RNA targets. Here, we mainly focused on the characteristics of known chloroplast RNA-binding proteins that protect exonuclease-sensitive sites in chloroplasts of vascular plants.

Highlights

The plastid is the result of an endosymbiotic event that occurred billion years ago and comprised the incorporation of a cyanobacterium into a eukaryotic, mitochondria-possessing cell
Chloroplast gene expression is predominantly governed on the level of post-transcriptional processes including RNA editing, methylation, polyadenylation, splicing, endo- and exonucleolytic digestion as well as translation
Newly evolved and vascular plant-specific RNA-binding factors encoded in the nuclear genome are required for protecting specific chloroplast RNAs at exo- and endoribonuclease-sensitive sites reflecting a fast-evolving RNA metabolism congruent with the diverging RNA targets

Summary

Introduction

The plastid is the result of an endosymbiotic event that occurred billion years ago and comprised the incorporation of a cyanobacterium into a eukaryotic, mitochondria-possessing cell. Over the course of evolution the chloroplast recruited many new features including the acquisition of introns, the ability to post-transcriptionally modify the RNA sequence, a process called RNA editing, and extensive processing events of the polycistronic pre-mRNAs leading to complex transcript patterns [14] These new features together with the coevolution of numerous mostly newly acquired, nucleus-encoded RNA-binding proteins involved in the expression of chloroplast genes opened up new possibilities for targeted and more precise regulation of gene products at many different steps that enable adaptive and developmentally flexible chloroplast biogenesis and plant viability [15]. It seems that the lifetime of chloroplast transcripts is mainly governed c 2018 The Author(s)

Conclusion and outlook

Summary