First Look at RNA Editing Patterns in a Primitive Insect Species

Jenn Hoskins
16th March, 2024

First Look at RNA Editing Patterns in a Primitive Insect Species

Image Source: Natural Science News, 2024

Key Findings

  • Researchers in China found thousands of RNA edits in the Coridius chinensis insect
  • Many RNA edits led to protein changes, suggesting a role in the insect's adaptability
  • One RNA edit in a cold-stress gene increased under cold conditions, hinting at its importance in temperature adaptation
RNA editing, a process by which the genetic code is subtly altered after it's been transcribed from DNA into RNA, has been a topic of considerable interest in the field of molecular biology. This post-transcriptional modification, specifically the adenosine-to-inosine (A-to-I) type, has been shown to diversify the proteins that an organism can produce, allowing for a more adaptable and flexible response to environmental changes[2]. Researchers from China Agricultural University have now shed light on this mechanism within the Hemiptera order of insects, which had previously been a blind spot in the study of RNA editing[1]. The A-to-I RNA editing process, which can be thought of as a molecular switchboard, allows a single gene to produce multiple proteins. This is achieved by the ADAR enzymes, which alter the nucleotide adenosine to inosine, interpreted as guanosine during protein synthesis, effectively changing the information that is translated into a protein[3]. This can alter the function of the protein, potentially allowing the organism to adapt to new conditions. Previous studies in other insect orders, such as Diptera, have highlighted the role of this editing in increasing proteomic diversity[4]. In the study by the team at China Agricultural University, the researchers assembled a chromosome-level genome of the Coridius chinensis, a species within the Hemiptera order, and generated RNA sequences from the insect's head to compare with its DNA sequence. This comparison allowed them to identify thousands of sites where RNA editing occurs. They discovered that many of these changes were nonsynonymous, meaning they resulted in the production of different amino acids, the building blocks of proteins, which could change the protein's function. Interestingly, the study also revealed that while nonsynonymous editing was common, conservation of these specific editing events across different insect orders was rare. This suggests that beneficial RNA editing may have evolved independently in different insect lineages, providing a fascinating glimpse into the evolutionary history of this mechanism. When the researchers exposed the insects to cold stress, they observed a decrease in overall RNA editing activity and a shutdown of general transcriptional processes. However, they found an intriguing exception in the potassium channel gene Shab. Despite the overall down-regulation, a specific editing site in Shab was significantly up-regulated in the cold, indicating it might play a role in the insect's response to temperature stress. The findings from this study provide evidence supporting the idea that RNA editing contributes to the adaptability and evolution of insects. This is in line with the "diversifying hypothesis" of RNA editing, which posits that this mechanism allows for a more dynamic proteome, capable of adjusting to environmental challenges[4]. In contrast to the A-to-I editing observed in insects, another type of RNA editing, C-to-U, occurs in plants and appears to serve a different purpose. This type of editing is believed to correct unfavorable mutations in the DNA, thus restoring the original, functional proteins rather than diversifying the proteome[4]. The research from China Agricultural University advances our understanding of the evolutionary significance of A-to-I RNA editing. It demonstrates that even within a single order of insects, there can be a diverse array of editing events, some of which may be crucial for survival in fluctuating environments. As the study of RNA editomes continues to expand across different clades, scientists are piecing together a more comprehensive picture of how organisms use RNA editing as a tool for adaptation and evolution.

GeneticsBiochemEvolution

References

Main Study

1) The first A-to-I RNA editome of hemipteran species Coridius chinensis reveals overrepresented recoding and prevalent intron editing in early-diverging insects.

Published 13th March, 2024

https://doi.org/10.1007/s00018-024-05175-6

Related Studies

2) The Many Roles of A-to-I RNA Editing in Animals: Functional or Adaptive?

https://doi.org/10.31083/j.fbl2810256

3) A full repertoire of Hemiptera genomes reveals a multi-step evolutionary trajectory of auto-RNA editing site in insect Adar gene.

https://doi.org/10.1080/15476286.2023.2254985

4) Differential adaptive RNA editing signals between insects and plants revealed by a new measurement termed haplotype diversity.

https://doi.org/10.1186/s13062-023-00404-7


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