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Title: RNA-editing enzymes ADAR1 and ADAR2 coordinately regulate the editing and expression of Ctn RNA
Award ID(s):
1723008
NSF-PAR ID:
10042911
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
FEBS Letters
Volume:
591
Issue:
18
ISSN:
0014-5793
Page Range / eLocation ID:
2890 to 2904
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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  1. Summary

    Hornworts are crucial to understand the phylogeny of early land plants. The emergence of ‘reverse’ U‐to‐C RNA editing accompanying the widespread C‐to‐U RNA editing in plant chloroplasts and mitochondria may be a molecular synapomorphy of a hornwort–tracheophyte clade. C‐to‐U RNA editing is well understood after identification of many editing factors in models likeArabidopsis thalianaandPhyscomitrella patens, but there is no plant model yet to investigate U‐to‐C RNA editing. The hornwortAnthoceros agrestisis now emerging as such a model system.

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    Both organelles inA. agrestisfeature high amounts of RNA editing, with altogether > 1100 sites of C‐to‐U and 1300 sites of U‐to‐C editing. The nuclear genome reveals > 1400 genes for PPR proteins with variable carboxyterminal DYW domains.

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  2. Abstract

    Plastid and mitochondrial RNAs in vascular plants are subjected to cytidine‐to‐uridine editing. The model plant speciesArabidopsis thaliana(Arabidopsis) has two nuclear‐encoded plastid‐targeted organelle RNA recognition motif (ORRM) proteins: ORRM1 and ORRM6. In theorrm1mutant, 21 plastid RNA editing sites were affected but none are essential to photosynthesis. In theorrm6mutants, two plastid RNA editing sites were affected:psbF‐C77 andaccD‐C794. BecausepsbFencodes the β subunit of cytochromeb559in photosystem II, which is essential to photosynthesis, theorrm6mutants were much smaller than the wild type. In addition, theorrm6mutants had pale green leaves and reduced photosynthetic efficiency. To investigate the functional relationship between ORRM1 and ORRM6, we generatedorrm1 orrm6double homozygous mutants. Morphological and physiological analyses showed that theorrm1 orrm6double mutants had a smaller plant size, reduced chlorophyll contents, and decreased photosynthetic efficiency, similar to theorrm6single mutants. Although theorrm1 orrm6double mutants adopted the phenotype of theorrm6single mutants, the total number of plastid RNA editing sites affected in theorrm1 orrm6double mutants was the sum of the sites affected in theorrm1andorrm6single mutants. These data suggest that ORRM1 and ORRM6 are in charge of distinct sets of plastid RNA editing sites and that simultaneous mutations inORRM1andORRM6genes do not cause additional reduction in editing extent at other plastid RNA editing sites.

     
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