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Discrimintion and Mapping of the Primary and Processed Transcripts in Maize Mitochondrion Using a Circular RT-PCR-based Strategy
Published on: July 29, 2019
Functional remodeling of RNA processing in replacement chloroplasts by pathways retained from their predecessors
Richard G Dorrell1, Christopher J Howe
1Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom. rd357@cam.ac.uk
Dinoflagellates like Karenia mikimotoi utilize RNA processing pathways from their original chloroplasts for newly acquired ones. This suggests ancient symbiont pathways are repurposed in serial endosymbiosis.
Area of Science:
- Evolutionary biology
- Cell biology
- Molecular biology
Background:
- Chloroplasts arise from endosymbiosis, with host pathways supporting their biogenesis.
- Serial endosymbiosis, where chloroplasts are replaced, is known, but the fate of host pathways is unclear.
Purpose of the Study:
- Investigate if pre-existing chloroplast biogenesis pathways in Karenia mikimotoi support replacement chloroplasts.
- Determine if RNA processing pathways are retained from ancestral symbionts.
Main Methods:
- Analyzing chloroplast transcripts in Karenia mikimotoi.
- Comparing RNA processing in K. mikimotoi with free-living relatives of replacement chloroplasts.
- Examining RNA processing in ancestral red algal-derived chloroplasts.
Main Results:
- Chloroplast transcripts in K. mikimotoi undergo 3' polyuridylylation and extensive sequence editing.
- These RNA processing pathways are absent in free-living relatives of the replacement chloroplast lineage.
- The observed RNA processing pathways are characteristic of ancestral, red algal-derived chloroplasts.
Conclusions:
- Karenia mikimotoi retains and utilizes RNA processing pathways from its original symbiont lineage for replacement chloroplasts.
- This demonstrates the repurposing of ancient pathways in serial endosymbiosis.
- Chloroplast biogenesis can be remodeled by retained pathways from previous symbioses.
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