Massive RNA Editing in Ascetosporean Mitochondria.

Area of Science:

• Protistology
• Parasitology
• Mitochondrial Biology
• RNA Editing

Background:

• Ascetosporeans are invertebrate parasites with known reduced mitochondrial function and absent organellar genomes in some orders.
• The mitochondrial nature of Paradinida, another ascetosporean order, remained uncharacterized due to a lack of genomic data.

Purpose of the Study:

• To investigate the mitochondrial characteristics and organellar genome status of Paradinida.
• To explore the presence and nature of RNA editing in Paradinida mitochondria.

Main Methods:

• Establishment of two Paradinida cultures.
• DNA and RNA sequencing analyses.
• Bioinformatic identification of RNA editing enzymes (PPR-DYW, ADAR-like).
• Immunofluorescence microscopy for ADAR-like localization.

Main Results:

• Paradinida possess non-reduced mitochondria with retained organellar genomes.
• Massive A-to-I and C-to-U RNA editing occurs in Paradinida mitochondrial genomes.
• Nonsynonymous edits in protein-coding genes suggest a restorative function.
• Identification of PPR-DYW and ADAR-like homologs, with ADAR-like potentially localized to mitochondria.

Conclusions:

• Paradinida exhibit unique mitochondrial and genomic features compared to other ascetosporeans.
• Extensive RNA editing in Paradinida mitochondria plays a crucial role in maintaining genetic information.
• Findings expand understanding of organellar RNA editing diversity and complexity in parasitic protists.