The mitochondrial and chloroplast
The collaborative non‐self‐recognition model for S‐
- NSF-PAR ID:
- 10246763
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 87
- Issue:
- 6
- ISSN:
- 0960-7412
- Page Range / eLocation ID:
- p. 606-616
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Summary mRNA s of the majority of land plants are modified through cytidine to uridine (C‐to‐U)RNA editing. Previously, forward and reverse genetic screens demonstrated a requirement for pentatricopeptide repeat (PPR ) proteins forRNA editing. Moreover, chloroplast editing factorsOZ 1,RIP 2,RIP 9 andORRM 1 were identified in co‐immunoprecipitation (co‐IP) experiments, albeit the minimal complex sufficient for editing activity was never deduced. The current study focuses on isolated, intact complexes that are capable of editing distinct sites. Peak editing activity for four sites was discovered in size‐exclusion chromatography (SEC) fractions ≥ 670 kDa, while fractions estimated to be approximately 413 kDa exhibited the greatest ability to convert a substrate containing the editing siterps14 C80.RNA content peaked in the ≥ 670 kDa fraction. Treatment of active chloroplast extracts withRN ase A abolished the relationship of editing activity with high‐MW fractions, suggesting a structuralRNA component in native complexes. By immunoblotting,RIP 9,OTP 86,OZ 1 andORRM 1 were shown to be present in active gel filtration fractions, thoughOZ 1 andORRM 1 were mainly found in low‐MW inactive fractions. Active editing factor complexes were affinity‐purified using anti‐RIP 9 antibodies, and orthologs to putativeArabidopsis thaliana RNA editing factorPPR proteins,RIP 2,RIP 9,RIP 1,OZ 1,ORRM 1 andISE 2 were identified via mass spectrometry. Western blots from co‐IP studies revealed the mutual association ofOTP 86 andOZ 1 with nativeRIP 9 complexes. Thus,RIP 9 complexes were discovered to be highly associated with C‐to‐URNA editing activity and other editing factors indicative of their critical role in vascular plant editosomes. -
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Summary Plants have mechanisms to recognize and reject pollen from other species. Although widespread, these mechanisms are less well understood than the self‐incompatibility (
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